Takeoff Performance - Flight Simulator Center

TP, Page 1

FLIGHTOPERATIONS

ENGINEERING

For Training Purposes Only Copyright © 2009 Boeing. All rights reserved

Takeoff Performance

TP, Page 2For Training Purposes Only Copyright © 2009 Boeing. All rights reserved

Takeoff Performance Issues

• The FARs concerning takeoff ensure the flight crew has the adequate performance resources to handle all foreseeable possibilities between the time the airplane is aligned with the runway until the airplane has cleared all critical obstacles.


Basic Takeoff Performance Regulations

• § 25.105 Takeoff.

• § 25.107 Takeoff speeds.

• § 25.109 Accelerate-stop distance

• § 25.111 Takeoff path.

• § 25.113 Takeoff distance and takeoff run.

• § 25.115 Takeoff flight path.

• § 25.117 Climb: general.


Takeoff Performance Issues

• Field length requirements

• Tire speed requirements

• Brake energy requirements

• Climb requirements

• Obstacle requirements


§ 25.105 Takeoff Performance

§ 25.105 Takeoff.

(a) The takeoff speeds described in §25.107, the accelerate-stop distance described in §25.109, the takeoff path described in §25.111, and the takeoff distance and takeoff run described in §25.113, must be determined—

(1) At each weight, altitude, and ambient temperaturewithin the operational limits selected by the applicant; and

(2) In the selected configuration for takeoff.

(b) No takeoff made to determine the data required by this section may require exceptional piloting skill or alertness.



§ 25.105 Takeoff.(c) The takeoff data must be based on—

(1) In the case of land planes and amphibians:(i) Smooth, dry and wet, hard-surfaced runways;

and

(ii) At the option of the applicant, grooved or porous friction course wet, hard-surfaced runways.

(2) Smooth water, in the case of seaplanes and amphibians; (3) Smooth, dry snow, in the case of skiplanes.



§ 25.105 Takeoff.

(d) The takeoff data must include, within the established operational limits of the airplane, the following operational correction factors:

(1) Not more than 50 percent of nominal windcomponents along the takeoff path opposite to the direction of takeoff (headwind), and not less than 150 percent of nominal wind components along the takeoff path in the direction of takeoff (tailwind)

(2) Effective runway gradients.


Field Length Considerations

• Ground acceleration capability

• Takeoff speeds

• Accelerate - Go considerations

• Accelerate - Stop considerations

• Field length calculation and considerations

TP, Page 9

FLIGHTOPERATIONS

ENGINEERING


Takeoff PerformanceGround Acceleration Considerations


Ground Acceleration Capability

FSlope

Σ Forces = Mass * Acceleration

Friction Drag Thrust


Ground Roll Acceleration Equation


Thrust - Drag - Friction - Fslope = Mass * Acceleration

T - D - μ ( W - L ) – W sin φ = aWg

For small angles, sin φ = φ in radiansΦ = runway slope (percent) ÷ 100

T - D - μ ( W - L ) - W φ = aWg



Rearranging

T - D - μ ( W - L ) - W φ = aWg

a = [ T - D - μ ( W - L ) - W φ ]gW

Combine Drag and Lift terms into one since both are a function of dynamic pressure

a = [ T - μ W - (D - μ L ) - W φ ]gW

a = [ T - μ W - (CD - μ CL ) q S - W φ ]gW



• Factors affecting airplane acceleration capability– Thrust - rating, altitude, temperature, bleeds– μ, rolling friction, function of the airplane’s gear– CD, CL airplane configuration, flap setting, CDL items– q, dynamic pressure, the faster the airspeed the worse

the acceleration– Weight, less weight results in better acceleration

– Hand calculations assume weight is constant – Computer programs take into account fuel burn

a = [ T - μ W - ( CD - μ CL ) q S - W φ ]gW


Workbook Problem

Do problem 7 in the performance workbook

• Determine the airplane’s all engine ground acceleration capability at 150 ktas for the following conditions.


Sample Acceleration Calculation

Acceleration - ft/s2

Speed - kts

0.0

1.02.0

3.0

4.0

5.06.0

7.0

8.0

9.0

0 20 40 60 80 100 120 140 160

Weight = 240000 lb SLOPE= 0Sea level, Std. day WIND= 0 μ 0.0165

NO ENG = 2 (CD-μ CL)= 0.08ALL ENGINE

V - GS V - TAS DYNAMIC - q F - THRUST F - SLOPE μW (CD- μCL)qS ACCEL - ft/s/s ACCEL - kt/s

0 0 0.00 35532 0 3960 0 9.0 5.320 20 1.35 34653 0 3960 211 8.7 5.240 40 5.42 33775 0 3960 845 8.4 5.060 60 12.19 32896 0 3960 1902 8.0 4.880 80 21.67 32017 0 3960 3382 7.6 4.5

100 100 33.86 31139 0 3960 5284 7.1 4.2120 120 48.75 30260 0 3960 7609 6.6 3.9140 140 66.36 29381 0 3960 10357 6.0 3.5150 150 76.18 28942 0 3960 11889 5.6 3.3


Ground Distance Calculation


Ground Distance Calculation

• To determine the field length required we need to determine how much runway it took to accelerate from brake release, ground speed = 0, to some other predetermined speed– Rotation speed– Engine failure speed


Fundamental Time-Distance Relationship

Δ sΔ t

Δ VΔ t

Δ Va

Velocity, V = or Δ s = V Δ t

Acceleration, a = or Δ t =

Substitute and solve for distance:

V Δ VaΔ s =


Example Time-Distance Relationship

Δ VΔ tAve accel. , a =

Accelerating from 0 ktas to 20 ktas in 4 seconds

20 - 0 ktas Ave accel. , a =4 seconds

5 kts /sec =

6076 feet/nm * 1 hour/3600 sec Ave accel. , a = 5 nm/hr sec *

8.44 ft / sec2Ave accel. , a =


( 20 - 0 ) ktas

Example Time-Distance Relationship

Substitute and solve for distance:

V Δ VaΔ s =

Accelerating from 0 ktas to 20 ktas in 4 seconds

8.44 ft / sec2Ave accel. , a =

( 20 + 0 ) ktas 2

8.44 ft / sec2Δ s =

(1.6878 ft/s/ktas )2

67.5 ft Δ s =



Integrating you obtain:

Where the beginning velocity is brake release, zero ground speed and the end velocity is the final ground speed for the calculation either VEF or VR

aVdVS

0∫=

Vg final



If acceleration, a, were a constant with velocity, then the integral would be easy.

Is acceleration constant with velocity during the ground run?

aVdVS

Vg final

0∫=



• No, acceleration, a, varies as a function of the airplanes airspeed.

• As the airplane’s speed increases the acceleration, a, reduces because of the thrust decay and the increase in q, dynamic pressure.


Speed - kts

0.0

1.0

2.0

3.04.0

5.0

6.0

7.08.0

9.0

0 20 40 60 80 100 120 140 160


Weight = 240000 lb SLOPE= 0Sea level, Std. day WIND= 0

NO ENG = 2ALL ENGINE

V - GS V - TAS ACCEL- ft/s/s ACCEL - kt/s S – Step - ft Sum S

0 0 9.0 5.3 020 20 8.7 5.2 64 6440 40 8.4 5.0 199 26460 60 8.0 4.8 346 61080 80 7.6 4.5 510 1120

100 100 7.1 4.2 697 1817120 120 6.6 3.9 917 2734140 140 6.0 3.5 1183 3917150 150 5.6 3.3 713 4630

Example of Distance Calculation

Total distance from brake release to 150 knots based on 20 knot steps = 4630 feet

Note: 1 knot step = 4635 feet


Summary of Ground Acceleration Calculation Methods

• Step integration on velocity is used in the computer programs to calculate the ground run with all engines operating

• Forces are a function of speed

• Current computer programs take credit for fuel burn off during ground run

• Average acceleration method is quick easy way to determine the effect of various parameters on the takeoff ground run


Items that Affect Ground Run

• Slope, how does slope affect ground run– Uphill slope, worse acceleration, longer distance– Downhill slope better acceleration, shorter distance

• Wind, how does wind affect ground run– At a given true airspeed the acceleration is the same– Effect of wind is to change the ΔV the airplane

accelerates through

ave

vea

aVV

SΔ

=


Effect of Wind

Effect of head wind is to reduce total ground speed increase;Effect of tail wind is to increase total ground speed increase.

Weight = 240000 lb SLOPE = 0Sea level, Std. day WIND = 20 μ 0.0165

NO ENG = 2 (CD-μCL)= 0.08ALL ENGINE

V - GS V - TAS DYNAMIC - q F - THRUST F - SLOPE μW (CD-μCL)qS ACCEL - ft/s/s ACCEL - kt/s

0 20 1.35 34653 0 3960 211 8.7 5.220 40 5.42 33775 0 3960 845 8.4 5.040 60 12.19 32896 0 3960 1902 8.0 4.860 80 21.67 32017 0 3960 3382 7.6 4.580 100 33.86 31139 0 3960 5284 7.1 4.2

100 120 48.75 30260 0 3960 7609 6.6 3.9120 140 66.36 29381 0 3960 10357 6.0 3.5130 150 76.18 28942 0 3960 11889 5.6 3.3

V - GS V - TAS ACCEL - ft/s/s ACCEL - kt/s S-Step-ft

0 20 8.7 5.220 40 8.4 5.0 6640 60 8.0 4.8 20860 80 7.6 4.5 36480 100 7.1 4.2 542

100 120 6.6 3.9 750120 140 6.0 3.5 1001130 150 5.6 3.3 614

Sum S

066

274639

1181193129323546


How does takeoff flap affect the takeoff distance ?

FLAPS LIMIT (ICAS)

1-250K2-250K5-250K

10-210K

15-200K25-190K30-175K40-162K

230K ALT FLAPEXTENDED

FLAPS

UP

12 5

10

15

253040

L

FLAPDOWN

FLAPUP0

1

2

5

10

15

25

30

40HORN

CUT OUT

1 2


Effect of Flap

• Increased takeoff flap will typically reduce the ground acceleration capability due to increased drag

But

• Acceleration will be to a lower speed (VR,V2)

• Overall effect will be shorter distance

ave

vea

aVV

SΔ

=


Effect of Thrust

• Direct relationship – More thrust - shorter distance– Less thrust - more distance

For example,

Same conditions as earlier only thrust has been reduced by 10%.

Result 14% increase in distance required to accelerate from 0 –150 for this example.

V - GS V - TAS ACCEL - ft/s/s ACCEL - kt/s S-Step-ft

0 8.0 4.820 7.8 4.6 7240 7.5 4.4 22360 7.2 4.2 38980 6.7 4.0 574

100 6.3 3.7 788120 5.8 3.4 1042140 5.2 3.1 1356

Sum S

072

295684

1258204630884444

150 4.9 2.9 824 5268

020406080

100120140150

ave

vea

aVV

SΔ

=


Engine Out Ground Acceleration

• What is different in the calculation of the distance required to accelerate following an engine failure– Failed engine’s thrust spins down as a function

of time, not airspeed– Pilot inputs rudder to steer the airplane

– Additional drag


Spindown Characteristics

ThrustTO Thrust

Time From the Event, Sec

Fuel CutThrottle Chop

Spindown Factor

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

0 2 4 6 8 10 12


Spindown Characteristics

• Fuel cut used for the continued takeoff following an engine failure– Lowest thrust

• Throttle chop is used for the AFM emergency stop calculation from an event just prior to V1

– Higher thrust conservative for stop calculation– Note: older airplanes used fuel cut following

engine failure just prior to V1


Calculation of Engine Out Accel/Distance

• Same equation used to calculate engine out acceleration

• Engine thrust now changing rapidly with time. Typically a step integration based on time is required. This becomes an iterative process.

a = [ T - μ W - ( CD - μ CL ) q S - W φ ]gW


Workbook Problem

• Do problem 8 in the performance workbook

• Determine the airplane’s engine inoperative ground acceleration capability at 150 ktas for the following conditions.


Engine Out Acceleration

Event Time V - GS V - TAS E1-FC E2 ACCEL - ft/s/s ACCEL - kt/s S-Step-ft Sum S

Eng Fail 0 150 150.0 1 1 5.4 3.21 153.3 153.3 0.22 1 2.3 1.4 256 2562 155.6 155.6 0.08 1 1.7 1.0 261 5173 157.3 157.3 0.038 1 1.5 0.9 264 7814 158.8 158.8 0.018 1 1.4 0.8 267 10474.9 160.0 160.0 0.01 1 1.3 0.8 242 1290

Speed - kts


0.01.02.03.04.05.06.07.08.09.0

0 20 40 60 80 100 120 140 160 180


Summary

• Looked at ground calculation for both all engine and engine out acceleration between two speeds– All engine is between brake release and engine

failure or rotation speed– Engine inoperative is between engine failure and

rotation speed

• Primary method of calculation is a step integration – All engine is step integration based on speed– Engine inoperative is based on time

TP, Page 41

FLIGHTOPERATIONS

ENGINEERING


Takeoff PerformanceAccelerate–Go Considerations and

Takeoff Speeds Definitions


Accelerate and Go Considerations

• Two types of accelerate and continued takeoff scenarios are considered in the field length calculation– All engines operating during the entire takeoff– Engine failure during the takeoff roll and

continued takeoff


§ 25.113 Takeoff Distance

(a) Takeoff distance is the greater of:(1) The horizontal distance along the takeoff path from

the start of the takeoff to the point at which the airplane is 35 feet above the takeoff surface, determined under § 25.111 (engine failure scenario)for a dry runway; or

(2) 115 percent of the horizontal distance along the takeoff path, with all engines operating, from the start of the takeoff to the point at which the airplane is 35 feet above the takeoff surface, as determined by a procedure consistent with §25.111 (engine failure scenario) .


§ 25.111 Takeoff Path

(a) The takeoff path extends from a standing start to a point in the takeoff at which the airplane is 1,500 feetabove the takeoff surface, or at which the transition from the takeoff to the en route configuration is completed and VFTO is reached, whichever point is higher.

In addition —

(2) The airplane must be accelerated on the ground to VEF, at which point the critical engine must be made inoperative and remain inoperative for the rest of the takeoff; and

(3) After reaching VEF, the airplane must be accelerated to V2.

(b) During the acceleration to speed V2, the nose gear may be raised off the ground at a speed not less than VR. However, landing gear retraction may not be begun until the airplane is airborne.


Takeoff Distance – Dry Runway

• Longer of:

– Engine failure during the takeoff roll - 25.113 (a)(1)35 feet, V2

VEF

V1VR VLO

all engineacceleration

1 Second

15%

– All Engines operating throughout the takeoff - 25.113 (a)(2)35 feet, V35 AE climb out speed

VLOVRall engine

acceleration


§ 25.113 Takeoff Distance

(b) Takeoff distance on a wet runway is the greater of —

(1) The takeoff distance on a dry runway determined in accordance with paragraph (a) of this section; or

(2) The horizontal distance along the takeoff path from the start of the takeoff to the point at which the airplane is 15 feet above the takeoff surface, achieved in a manner consistent with the achievement of V2 before reaching 35 feet above the takeoff surface, determined under §25.111 for a wet runway


Wet Takeoff Distance – Longer of:

15%

35 feet, V35 AE climb out speed

VLOVRall engine

acceleration

– Takeoff distance determined in 25.113 (a)35 feet, V2

VEF

V1 VR VLOall engine

acceleration1 Second

15 feet, V2VEF

V1 VR VLOall engine


Or - Takeoff distance determined in 25.113 (b)

DRY

WET


Factors Affecting Takeoff Distance

• Anything which affects acceleration capability– Thrust (alt and temp), flap setting, slope

• Anything which affects ΔV – Wind, altitude, temperature, flap setting– Choice of V1, VR, V2

• Definition/selection of V1, VR, V2 directly affects the takeoff distance required


Takeoff Speeds Definitions


25.107 (a) (1) - VEF - Critical Engine Failure Speed

VEF is the calibrated airspeed at which the critical engine is assumed to fail. VEF must be selected by the applicant, but may not be less than VMCG determined under §25.149(e).

What is a critical engine?


V1 - Takeoff Decision Speed (Action Speed)

• From FAR 1.2

– V1 means the maximum speed in the takeoff at which the pilot must take the first action (e.g., apply brakes, reduce thrust, deploy speed brakes) to stop the airplane within the accelerate-stop distance.

– V1 also means the minimum speed in the takeoff, following a failure of the critical engine at VEF, at which the pilot can continue the takeoff and achieve the required height above the takeoff surface within the takeoff distance.



• From FAR 25.107 (a)(2)….V1 may not be less than VEF plus the speed gained with critical engine inoperative during the time interval between the instant at which the critical engine is failed, and the instant at which the pilot recognizes and reacts to the engine failure, as indicated by the pilot's initiation of the first action (e.g., applying brakes, reducing thrust, deploying speed brakes) to stop the airplane during accelerate-stop tests.



• Maximum speed to initiate stop

• Minimum speed for engine failure recognition and to continue the takeoff– 1 sec allowed between VEF and V1 for recognition of

engine failure (727-100, 3 seconds)– V1 ≤ VR rotation speed– V1 ≤ Vmbe maximum brake energy speed– V1 ≥ Vmcg minimum control speed on the ground (older

airplanes 737-100/-200/Adv 747-100/-200/-300, 707 etc.– V1 ≥ V1mcg V1 for minimum control speed on the ground

(newer airplanes 757, 767 etc.)



• A “legal” V1 is any speed which can meet the previously mentioned criteria and result in the distance calculation staying within the available distance

• Some choices of V1 have advantages - will explore later


Vmcg, Ground Minimum Control SpeedVmcg, Ground Minimum Control Speed

• FAR 25.149(e) - Minimum speed on ground– Critical engine fails– Airplane is controllable– Primary aerodynamic controls only

– No nose wheel steering credit– Must be able to safely continue the takeoff with normal

piloting skills. – Maximum rudder pedal force required -150 lb– Maximum deviation from runway centerline is 30 feet

Note: may be parallel to centerline, not required to return to centerline


Vmcg, Ground Minimum Control SpeedVmcg, Ground Minimum Control Speed

Engine FailureAsymmetric thrust

Apply rudderNo nose wheel steering

Maximum deviation,

30 feet

30’


V1mcgV1mcg

• The V1 speed that goes with VEF = VMCG

• Accounts for the airplane’s acceleration during one second time delay between VEF = VMCG and V1


Vmcg, V1mcg Ground Minimum Control SpeedVmcg, V1mcg Ground Minimum Control Speed

Engine FailureAsymmetric thrust

Apply rudderNo nose wheel steering

Maximum deviation,

30 feet

30’

Vmcg V1mcg = Vmcg + 1 second

Note on older airplanes V1 = Vmcg, (737-1/2/ADV, 707, 747-1/2/3/4)


Vmca, Minimum Control Speed, Air

• FAR 25.149– (b) VMC is the calibrated airspeed at which,

– Critical engine is suddenly made inoperative– Possible to maintain control of the airplane – Maintain straight flight – Angle of bank of not more than 5 degrees

(measure of control)


FAR 25.149, Vmca

(c) VMC may not exceed 1.13 VSR (1g) (1.2 VS FAR) with:

(1) Maximum available takeoff power or thrust on the engines

(2) The most unfavorable center of gravity;

(3) The airplane trimmed for takeoff;

(4) The maximum sea level takeoff weight (or any lesser weight necessary to show VMC);

(5) Most critical takeoff configuration with the landing gear retracted

(6) The airplane airborne and the ground effect negligible

continued


FAR 25.149, Vmca

• FAR 25.149(d) – The rudder (pedal) forces required to maintain

control at VMC may not exceed 150 pounds – Nor may it be necessary to reduce power or thrust

of the operative engines. – During recovery, the airplane may not assume any

dangerous attitude – Or require exceptional piloting skill, alertness, or

strength to prevent a heading change of more than 20 degrees.

continued


• Vmca is the minimum speed in the air where the one engine inoperative directional control can be maintained with a maximum of 5 degrees of bank at the most adverse conditions.

• Vmca is used in determining the minimum VR and V2

Vmca

Force due to 5o bank

Force due to engine inoperative


Vmu, Minimum Unstick Speed

• FAR 25.107(d) VMU is the calibrated airspeed

– At and above which the airplane can safely lift off the ground, and continue the takeoff.

– VMU speeds must be selected by the applicant throughout the range of thrust-to-weight ratios to be certificated.


• Vmu is the minimum speed at which the airplane can fly:– Takeoff flap– Thrust – Weight

• Vmu is used in determining the minimum allowable rotation speed.

Vmu, Minimum Unstick Speed



VR, Rotation Speed

• FAR 25.107– (e) VR, in terms of calibrated airspeed, must be

selected in accordance with the conditions of paragraphs (e) (1) through (4) of this section: – (1) VR may not be less than--

(i) V1; (ii) 105 percent of VMC; (iii) The speed that allows reaching V2 before

reaching a height of 35 feet above the takeoff surface; or

(iv) A speed that, meets Vmu /rapid rotation requirements, to be explained later


VR, Rotation Speed

• FAR 25.107(e)(2) For any given set of conditions (such as weight,

configuration, and temperature),– A single value of VR, must be used to for both the

– One-engine-inoperative– All-engines operating provisions


VR, Rotation Speed

• FAR 25.107(e)(3) It must be shown that the one-engine-

inoperative takeoff distance, using a rotation speed of 5 knots less than VR established in accordance with paragraphs (e)(1) and (2) of this section, does not exceed the corresponding one-engine-inoperative takeoff distance using the established VR. The takeoff distances must be determined in accordance with Section 25.113(a)(1). – Manufacturer shows compliance with this

requirement during certification


VR, Rotation Speed

•FAR 25.107(e)(4) Reasonably expected variations in service from the

established takeoff procedures for the operation of the airplane (such as over-rotation of the airplane and out-of-trim conditions) may not result in unsafe flight characteristics or in marked increases in the scheduled takeoff distances established in accordance with Section 25.113(a).

Recommended stabilizer trim setting is related to this item


• A horizontal stabilizer trim setting is used during all takeoffs. These settings are designed to produce an in-trim condition at:

- The proper all-engines operating climb-out speeds of V2 + 15 to 25 kts (V2 + 10 to 20 for 3 and 4 engine airplanes

- The proper one-engine inoperative climb-out speeds V2

- Reasonable column forces for the pilots

• Trim setting is provided as a function of the airplane weight, C.G., flap setting, and engine thrust level.

Takeoff Horizontal Stabilizer Trim Setting


Takeoff Horizontal Stabilizer Trim Setting

Thrust

Weight

Lift

Lift(downward)

Downward force from the horizontal tail is used to rotate the airplane about the main gear for takeoff rotation, and to hold the airplane in the correct pitch attitude for the climb-out from the airport after liftoff.

(Drag contribution to moment about CG is negligible)


Horizontal Stabilizer Movement


Horizontal Stabilizer Jackscrew


Trim Setting on Flight Deck

767-300 Example

• Stab trim must be in the green band at the time of takeoff thrust setting

• If not, takeoff configuration warning horn will sound when thrust levers are advanced to TO thrust

• Caution: Stab should be set at recommended stab setting to ensure “normal”rotation characteristics and column forces


• For a given 737 at:– 60,000 kg, flap 15, c. g. 12%– Recommended Stab trim = 8 units

• What would happen if 3 units of stab trim was used instead of the recommended 8 ?

Stabilizer Mis-trim


Stabilizer Mis-trim

8

3 • Inside green band – no takeoff configuration warning horn.

• First sign of problem would be at rotation• Column force required to

rotate at VR would be higher• Potential for increased

distance to attain 35 feet• Initial climb out speed may

be higher

• Inside green band – no takeoff configuration warning horn.

• First sign of problem would be at rotation• Column force required to

rotate at VR would be higher• Potential for increased

distance to attain 35 feet• Initial climb out speed may

be higher


• What about the opposite case ?

• Now consider a 60,000 kg airplane at flaps 15 with a computed c. g. of 35 %

– Recommended trim – 3 units

• What would happen if 8 units of stab trim was used instead of the recommended 3 units ?

Stabilizer Mis-trim


Stabilizer Mis-trim

8

3 Inside green band – no takeoff configuration warning horn.

Possible autorotation

Potential tail-strike

Inside green band – no takeoff configuration warning horn.

Possible autorotation

Potential tail-strike


• These two mis-trim cases are extremes but they are used to illustrate a point

• Being in the green band means there will not be a takeoff configuration warning

But

• It does not mean the column forces and airplane behavior will be desirable

Stabilizer Mis-trim


VLOF, Liftoff Speed

• FAR 25.107(f) – VLOF is the calibrated airspeed at which the

airplane first becomes airborne. – VLOF is used in determining the minimum rotation

speed based on the minimum unstick criteria– VLOF is used to meet Vmu /rapid rotation

requirements– To be explained later


V2, Takeoff Safety Speed

• 25.107(c) V2, in terms of calibrated airspeed, must be selected by the applicant to provide at least the gradient of climb required by Sec. 25.121(b) but may not be less than--(1) V2MIN, and(2) VR plus the speed increment attained before reaching

a height of 35 feet above the takeoff surface.


V2MIN

• 25.107(b) V2 MIN, in terms of calibrated airspeed, may not be less than--– 1.2 VS for FAR stall certifications – 1.13VS1g for 1-G stall certifications– 1.10 times VMC established under Sec. 25.149. – A speed that provides the maneuvering capability

specified in §25.143(h) Not applicable to 1.2 FAR stall certifications


25.107 (g) VFTO

• Final takeoff – flaps up

(g) VFTO, in terms of calibrated airspeed, must be selected by the applicant to provide at least the gradient of climb required by §25.121(c), but may not be less than—

– (1) 1.18 VSR; and – (2) A speed that provides the maneuvering

capability specified in §25.143(g).

Not applicable to 1.2 FAR stall certifications


FAR 25.143(h)

• (g) The maneuvering capabilities in a constant speed coordinated turn at forward center of gravity, as specified in the following table, must be free of stall warning or other characteristics that might interfere with normal maneuvering:

– New for 1-g stall certifications– Prior certifications did not call out

any specific requirements


FAR 25.143(h)

Maneuvering bankConfiguration Speed angle in a Thrust power setting

coordinated turn------------------------------------------------------------------------------------------------------------------------Takeoff V2 30° Asymmetric WAT-Limited. \1\Takeoff V2 + XX \2\ 40° All-engines-operating climb.\3\Enroute VFTO 40° Asymmetric WAT-Limited. \1\Landing VREF 40° Symmetric for -3° flight path angle.------------------------------------------------------------------------------------------------------------------------\1\ A combination of weight, altitude, and temperature (WAT) such that the thrust or power setting produces the minimum climb gradient specified in § 25.121 for the flight condition.\2\ Airspeed approved for all-engines-operating initial climb.\3\ That thrust or power setting which, in the event of failure of the critical engine and without any crew action to adjust the thrust or power of the remaining engines, would result in the thrust or power specified for the takeoff condition at V2, or any lesser thrust or power setting that is used for all-engines-operating initial climb procedures.


Do problem 9 and 10.

Determine “book” takeoff speeds


Baseline Takeoff Speed Determination

Boeing baseline takeoff speeds obtained fromQRH, FMC and FPPM target the minimum field length


Takeoff Speed Determination

• Determine VR and V2

– Manufacturer determines VR and V2 as a function of takeoff flap, thrust (note: thrust generalizes for altitude and temperature), weight– Minimum unstick based speed schedule sets

minimum VR allowed– Stall speed based speed schedule - sets

minimum V2 allowed– Other - tail clearance considerations, Vmca


Minimum Unstick Based TO Speeds

• First determine takeoff speeds based on the minimum unstick considerations(1) Determine minimum unstick speed from flight test

– Rotate to tail skid contact at 10-20 knots below estimated Vmu

– Flap, thrust, weight

Vmu



(2) Generalize Vmu as a function of flap, thrust and weight

Note: Vs ref is a speed based on a reference CL for each flap. 4-8 data points at each flap.

Vmu

Vs ref

Thrust / WeightLowEngine inoperative

HighAll Engine

..

.

. . .. . .. .

...

.



(3a) Multiply Vmu EI by 5% to obtain minimum allowable engine inoperative liftoff speed

(3b) Multiply Vmu AE by 10% to obtain minimum allowable all engine liftoff speed


HighAll Engine

1.05 Vmu = VLO min EI

Vmu

1.1 Vmu = VLO min AE

Vmu

Vs ref



• Steps 1-3 identified the minimum allowable lift off speeds per FAR 25.107

• Next, the rotation speed associated with the minimum allowable lift off speed needs to be determined



• The rotation speed is based on a the maximum practical rotation rate (rapid rotation) - typically 4-6 deg/sec– Rapid rotation results in the minimum velocity

difference between rotation and liftoff– Angle of attack required to fly is rapidly achieved not

allowing time for much velocity change– Rapid rotation minimum ΔVRotation to Lift off

– Therefore the result is the maximum (conservative) rotation speed

– The ΔVRotation to Lift off determined in flight test is subtracted from the minimum allowable VLO based on VMU



VVs ref


HighAll Engine

1.05 Vmu = VLO min EI 1.1 Vmu = VLO min AE

ΔVRapidRotation ΔVRapid RotationVR EI

VR AE



• Summary– If airplane is rotated at normal rotation rates

(2-3 deg/sec) the resultant VLO will exceed minimum FAR requirement of 1.05 VMU EI and 1.1 VMU AE

– If airplane is rotated at rapid rotation rates (4-6 deg/sec) the resultant VLO will just meet the minimum FAR requirement of 1.05 VMU EI and 1.1 VMU AE



VR AE

Rapid.

NormalRapid.

Normal

VVs ref

Thrust / WeightLowEngine Inoperative

HighAll Engine

1.05 Vmu

1.1 Vmu

VR EI



• Determine final rotation speed schedule based on minimum unstick requirements

• Previous analysis will result in a different VR with an engine inoperative and all engines operating

• Must have a single value of VR for any given takeoff

• Replot all engine VR at the engine inoperative T/W ratio



• VR AE replotted at EI T/W

• Final VR is the higher value of EI or AE

VR AE

VVs ref


HighAll Engine

VR EI



• Finally, from normal rotation rate testing, determine the V2 speed which is associated with the VR which meets the minimum unstick criteria

Rotate at VRbased on VMUcriteria

Measure resulting speed when airplane reaches 35 feet - V2based on VMU criteria




Rotation Speed

V2 , Takeoff Safety Speed

V35 , All Engine Speed at 35’

Liftoff Speed

VVs ref


HighAll Engine


VMUTakeoff Speed Build Up

Eng. Inop.VMU

All Eng.VMU

FAR Eng.Inop. Factor

5%

FAR All Eng. Factor

10 %

Minimum legal LO speedbased on rapid rotation abusive TO condition

Eng.Inop.

AllEng.

Given: WeightAltitudeTemp.Flap



Eng. Inop.VMU

All Eng.VMU


5%

FAR All Eng. Factor

10 %


Eng.Inop.

AllEng.


VR basedon rapid

rotation TOcondition



Eng. Inop.VMU

All Eng.VMU


5%

FAR All Eng. Factor

10 %


Eng.Inop.

AllEng.


VR basedon greater of EI

and AE VR’s which are based on Min Unstick criteria



Eng. Inop.VMU

All Eng.VMU


5%

FAR All Eng. Factor

10 %


VR basedon greater of EI

and AE VR’s which are based on Min Unstick criteria

VLO and V2 based on normal rotation

technique

VR

V2


Stall Speed Based TO Speeds

• Determine V2 from factored stall speed

• From normal rotation rate testing– Determine the engine out speed increment between

V2 based on the stall speed criteria and VR

– Adjust the engine out VR speeds to an all engine T/W– Determine the all engine 35 foot speed


V2 , Takeoff Safety Speed

Rotation Speed

Liftoff Speed

Stall Speed Based TO Speeds

1.2 or 1.13 as appropriate

V35 , All Engine Speed at 35’

VVstall


HighAll Engine


V2Takeoff Speed Build UpGiven: Weight

AltitudeTemp.Flap

VR

V2 based on stall speed

VR and VLO based on normal rotation

technique


Takeoff Speeds Calculation

• For the given weight, altitude, temperature, flap, the takeoff speeds (VR and V2) are calculated based on – Vmu takeoff speed criteria

AND– Stall speed takeoff speed criteria

• Higher of the two is the most limiting and the speed which is published


Final Takeoff SpeedGiven: Weight

AltitudeTemp.Flap

VR

V2 based on stall speed

V2

VR based on minunstick criteria

The final takeoff speeds are the higher of the speeds based on min unstick or the speeds

based on stall speed.

In this graphical example the min unstick speeds would be limiting.


VMUTakeoff Speed Build UpNumerical Example – Given Flap, Weight, Alt, Temp

136V2 based on VMUcriteria

3Δ(VLO-V2) based on normal rotation

128127128VR based on VMUcriteria

5Δ(VR-VLO) based on normal rotation

133VLO based on VMUcriteria

-6-3Δ(VR-VLO) based on rapid rotation

133

121

All Engine

131Min LO speed (factored VMU)

125VMU

Final VMU takeoff speeds

Engine Inop.Eng. Inop.


VS Based Takeoff Speed Build UpNumerical Example – Given Flap, Weight, Alt, Temp

-5Δ(VR-VLO) based on normal rotation

127VR based on Vscriteria

132VLO based on Vscriteria

-3Δ(VLO-V2) based on normal rotation

135V2 = 1.13 VS 1G

Eng. Inop.


Final Speeds for this Numerical Example – Given Flap, Weight, Alt, Temp

127

132

135

Stall Speed Based

VR based on VMUcriteria

VLO based on VMU criteria

V2 based on VMUcriteria

128VR based on Vscriteria

133VLO based on Vscriteria

136V2 = 1.13 VS 1G

Min UnstickBasedStall Speed Based

For this example the min unstickSpeeds would be limiting


Takeoff Speeds Calculation

• Long aft body airplanes are typically limited by Vmutakeoff speed criteria– Examples 757, 727-200

• Shorter aft body airplanes are typically limited by stall takeoff speed criteria– Examples 737-200/-200 Adv

• Most airplanes have some flaps Vmu limited and some stall speed limited


Other Takeoff Speed Selection Criteria

• Tail Clearance– Examples 757-300, 737NG’s at flaps 1 and 5,

767-400, 777-300 etc.– In these examples VR and V2 are increased

above the minimum allowable for VMU and VStallbased speed schedules because of desired tail clearance margin

– Height and angle are considered



Tail Clearance

• Tail clearance values in the FCTM are based on:– Baseline certified speed schedules

QRH / FMC speedsMin field length speeds“normal” rotation rates

– Higher VR and V2 associated with improve climb will provide additional margin to tail strike


Use of Takeoff Speeds in Distance Calculation

• The takeoff speeds are a very important parameter in determining the takeoff distance required.

• Higher VR and V2, the more runway required for the takeoff

or

• The lower the field length limited weight


Douglas VR, V2 choice

• DC-9 used similar philosophy to Boeing traditional method

• 717, DC-10, MD series airplanes use dial-a-flap– Continuously variable flap setting in 1/10 degree

increments– VR and V2 chosen to meet perceived need of flap

setting• At high number, steeper angle flap settings VR and

V2 speeds are selected to be as low as possible catering to field length criteria

• At low number, shallower flap settings VR and V2speeds are selected to maximize climb capability catering to climb limit criteria


Flare Distance and Considerations

35 feet, V2VEF

V1VR VLO


1 Second

The Flare Distance is what we typically call the distance from rotation to 35 feet

Distance depends on thrust, weight, ground speed and rotation rate


Rotation Rate Effect

35 feet, V2

VR VLO 35 feet, V2

VR VLO

Normal Rotation Rate – 2 ½ to 3 degrees per second

Slow rotation – longer distance, higher liftoff speed, higher V2



Flare Distance and Considerations

Flare Time

02468

101214

0.1 0.2 0.3 0.4

Thrust/Weight

Time (sec.) Liftoff - 35 ftRotation - 35 ft

Flare is a function of thrust to weightAFM data has an implied rotation rate


Accelerate – Go Distance CalculationTakeoff Distance - TODA

Takeoff Distance Calculation


FAR 25.113 Takeoff Distance

(a) Takeoff distance is the greater of:(1) The horizontal distance along the takeoff path from

the start of the takeoff to the point at which the airplane is 35 feet above the takeoff surface, determined under § 25.111 (engine failure scenario)for a dry runway; or

(2) 115 percent of the horizontal distance along the takeoff path, with all engines operating, from the start of the takeoff to the point at which the airplane is 35 feet above the takeoff surface, as determined by a procedure consistent with §25.111 (engine failure scenario) .

Will look at the all-engine accelerate go distance first.


Takeoff Distance – Dry Runway

• Longer of:

– Engine failure during the takeoff roll - 25.113 (a)(1)35 feet, V2

VEF

V1VR VLO


1 Second

15%

– All Engines operating throughout the takeoff - 25.113 (a)(2)35 feet, V35 AE climb out speed

VLOVRall engine

acceleration


1.15 All Engine Distance Calculation

• For given weight, altitude, temperature, flap– Determine VR and V2

– Determine ground distance (Sground) from brake release to rotation speed with all engines operating – Step integration

– Determine flare distance from rotation to 35 feet (SR-35) with all engines operating– Flight test data - time versus T/W, function of flap

– Add Sground + SR-35 and then multiply by 1.15– (Sground + SR-35 ) 1.15

“Legal” Accelerate – Go distance with all engines operating


Sample Calculation - All Engine Distance

(1) Assume we are using earlier developed All Engine Acceleration Data

(2) Assume VR = 160, V2 = 165 and V35 = 180

SGround AE Brake Release to R = Step integration BR to VR = 5437 feet

ALL ENGINE

V - GS V - TAS ACCEL - ft/s/s ACCEL - kt/s S-Step-ft Sum S

0 0 9.0 5.3 020 20 8.7 5.2 64 6440 40 8.4 5.0 199 26460 60 8.0 4.8 346 61080 80 7.6 4.5 510 1120100 100 7.1 4.2 697 1817120 120 6.6 3.9 917 2734140 140 6.0 3.5 1183 3917150 150 5.6 3.3 713 4630160 160 5.3 3.1 808 5437


(3) Determine distance from Rotation to 35 feet • ΔtR-35 AE from flight test x VAve R-35

• SR-35 = 5.7 sec. x (160 + 180)/2 kts x 1.6878 ft/s• 1635 feet

Sample Calculation - AE Dist.

kts

continued

Flare Time

02468

101214

0.1 0.2 0.3 0.4

Thrust/Weight



Sample Calculation - AE Dist.

(4) Add up the ground distance and flare distance to get the total all engine distance– AE Dist. = 5437 + 1635 = 7072 feet

(5) Factor for the final AE Dist.– 1.15 x AE Dist. = 7072 x 1.15 = 8133 feet

continued


All Engine Accelerate – Go Distance

0

20

40

60

80

100

120

140

160

180

200

0 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000Distance - Feet

All Engine Acceleration All Engine Rot-35 feet Plus 15%

V2+15 = 180V2 = 165 ktsVR= 160 kts

All Engine AccelerationGround attitude

1.15 all engine distance

FlareRotation to 35 ft

Minimum required distance to meet the all engine requirement for this takeoff – 8133 feet


What Would Affect AE Distance Calculation?

• Thrust - rating, altitude, temperature, bleed

• Drag - Flap selection

• VR - Higher VR larger ΔV

• Choice of V1 - no effect

• Other ?


EI A-G Distance Calculation

• Choose V1 speed

• Calculate distance to assumed engine failure - 1 sec prior to V1

– S Ground BR to EF - This distance is based on all engine thrust

• Calculate distance from VEF to VR

– S EF to R - This distance is based on spindown of failed engine plus operating engine thrust

• Determine flare distance from rotation to 35 feet (SR-35)– Flight test data - time versus T/W, function of flap



0 9.0 5.3 020 8.7 5.2 64 6440 8.4 5.0 199 26460 8.0 4.8 346 61080 7.6 4.5 510 1120100 7.1 4.2 697 1817120 6.6 3.9 917 2734140 6.0 3.5 1183 3917150 5.6 3.3 713 4630160 5.3 3.1 808 5437

020406080100120140150160

Brake Release

VEF

Sample Calculation - EI A-G Distance

(1) Assume we are using earlier developed AE and EI Acceleration Data

(2) Assume VR = 160, V2 = 165

(3) Further assume V1 = 152.3 and VEF =150

SGround AE BR to EF = Step integration BR to EF = 4630 feet

ALL ENGINE


(4) Determine distance from engine failure to rotationSample Calculation - EI A-G Dist.

2657270.81.310.0160.0160.010.1VR

26302690.81.310.0159.9159.910

23612680.81.310.0159.2159.29

20932670.81.310.0158.4158.48

18262650.81.310.0157.6157.67

15612640.81.310.0156.8156.86

12972630.81.310.01156.1156.15

10342610.81.410.018155.3155.34

7732600.91.510.038154.4154.43

5132581.01.710.08153.5153.52

2552551.42.310.22152.3152.31

03.25.41150.0150.00Eng Fail

Sum SS-

Step-ftACCEL

- kt/sE2E1-FCV -

TASV - GSTimeACCEL - ft/s/s

1

Eng. Fail

V1

VR


Sample Calculation - EI A-G Dist.

(5) Determine the flare distance

• ΔtR-35 EI from flight test x VAve R-35

• SR-35 = 9 sec. x (160 + 165)/2 kts x 1.6878 ft/s

• 2468 feet kts

continued

Flare Time

02468

101214

0.1 0.2 0.3 0.4

Thrust/Weight



Sample Calculation - EI A-G Dist.

(6) Add up the ground distance and flare distance to get the total EI A-G distance based on a V1 of 152.3 kts

• SGround AE BR to EF + (S EF - V1 + S V1 - R) + SR-35

4630 + 2657 + 2468 = 9755 feet

continued


Engine Inoperative Accelerate – Go Distance

0

20

40

60

80

100

120

140

160

180

200

0 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000Distance - Feet

Gro

und

Spee

d - k

ts

All Engine Acceleration Eng Fail @ 150, V1=152.3 All Engine Rot-35 feet

Plus 15% Eng out flare VEF 150

V2+15 = 180V2 = 165 ktsVR= 160 ktsV1 = 152.3 kts

All Engine Acceleration

Engine inoperative acceleration to 35 feet- 9755 feet



What Would Affect A-G Distance Calculation?

What happens if a higher V1 is chosen, for example VR which is

160 kts for this example ?


Engine Inoperative Accelerate – Go Distance

0

20

40

60

80

100

120

140

160

180

200

0 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000Distance - Feet

All Engine Acceleration Eng Fail @ 157.8, V1=160 All Engine Rot-35 feet

Plus 15% Eng out Flare VEF=157.8

V2+15 = 180V2 = 165 ktsVR= 160 ktsV1 = 160 kts


Engine inoperative acceleration to 35 feet- 7982 feet



Summary of TO Distance - Example

For the example shown:

1.15 All Engine Distance = 8133 feet

Engine inoperative accel-go distance

V1 = 152.3 then 9755 feet

V1 = VR 160 then 7982 feet

Will use this information later.

TP, Page 145

FLIGHTOPERATIONS

ENGINEERING


Accelerate and Stop Considerations



Accelerate-Stop Distance

• The sum of the distances necessary to accelerate to V1 and the distances to stop

Accelerate - Stop

VEventV1


1 Second

V Full Braking Configuration

maximummanual braking

Transition

Dry runway - no reverse thrustWet runway - reverse thrust credit


Ground Deceleration Capability

RetardingForce due to wheel brakes Drag

Thrust

FSlope

Forward - spindown, idleReverse - spinup, detent, max

Σ Forces = Mass ∗ Acceleration



Thrust - Drag - Brake Force - Fslope = Mass ∗ Accel

Small angles sin φ = φ in radians

T – D – μΒ ( W – L ) - W φ = aWg

T – D – μΒ ( W – L ) – Wsin φ = aWg




Rearranging

a = [ T - D - μΒ ( W - L ) - W φ ]gW

StoppingForce due to Wheel Brakes

= μΒ ( W - L ) = FΒ

μΒ = Airplane Braking Coefficient

T – D – μΒ ( W – L ) – W φ = aWg


Airplane Braking Coefficient

• Airplane Braking Coefficient - μΒ

– Percentage of the weight on the wheels (W-L) converted into an airplane stopping force FΒ

– Note: Weight on all airplane wheels not just main wheels which have wheel brakes

– Not tire to ground friction

• Brake Force - FB

– Airplane stopping force due to wheel brakes


Brake Force Generalization - Dry runway

FB ,BrakeForce

W - LAverage Weight

on Wheels

WVΒg2

Initial Braking Energy

Anti-skid limited regionFB

W - LμΒ = = Constant

Torque Limited RegionFΒ = Constant

Fade Region

Dry runway performance - Maximum manual braking


Anti-skid Limited Region

Typical dry runway certification value

0.35 to 0.42

Limited by the runway friction capabilityAnti-skid limits brake pressure because a skid is sensed

FB ,BrakeForce

WVΒg2

Initial Braking EnergyW - L

Average Weighton Wheels




Torque Limited Region

FB ,BrakeForce

W - LAverage Weight

on Wheels

WVΒg2


Torque Limited RegionFΒ = Constant

Limited by the torque capability of the wheel brakes – the internal friction between the rotors and stators


Fade Region

FB ,BrakeForce

W - LAverage Weight

on Wheels

WVΒg2


Fade Region

During a high energy stop theheat builds up internally in the brake.Eventually, the rotors and stators cannot produce as much friction - Steel brake characteristic.


Wheel Brake Assembly

Rotor, moveswith wheel

Stator, attached to housing

Pistons

Pistons


Testing to Determine Brake Force

• Accelerate the airplane to predetermined test stopping speed

• Flight crew actions to stop airplane– Brakes on– Throttles to idle– Spoilers up

• Measure distance required to stop


Testing to Determine Brake Force

• Solve for airplane brake force and airplane braking coefficient– Determine what the force/coefficient must have been

for the airplane to stop in the measured distance

• Do many stops at different W-L’s and WVΒ2 ’s

generalize the data into stopping force chart

• Testing done at forward c.g. – Less weight on main gear, conservative

continued


Sample Calculation of Deceleration

a = [ T - D - μΒ ( W - L ) - W φ ]gW

SpindownTC

GroundSpeed

Total Thrustlbs

Draglbs

W-Llbs

FBlbs

ForceSlope

Accelft/s2

Accelkt/sEvent Time

Brakes on 0 1.00 160 57006 10664 182537 69364 0 -3.1 -1.8Throttle Chop 0.3 1.00 159 57006 10591 182931 69514 0 -3.1 -1.8

0.5 1.00 159 56721 10543 183194 69614 0 -3.1 -1.90.7 0.99 159 56664 10493 183459 69715 0 -3.2 -1.9

Spoilers up 0.701 0.99 159 56664 23730 281573 106998 0 -9.9 -5.91.3 0.64 155 36199 22687 279746 106303 0 -12.4 -7.42.3 0.30 148 17102 20582 276057 104902 0 -14.5 -8.63.3 0.22 139 12370 18252 271976 103351 0 -14.7 -8.74.3 0.18 131 10147 16046 268111 101882 0 -14.5 -8.66.3 0.14 113 7810 12109 261214 99261 0 -13.9 -8.28.3 0.112 97 6385 8847 255500 97090 0 -13.4 -7.910.3 0.092 81 5245 6193 250850 95323 0 -12.9 -7.714.3 0.064 50 3648 2400 244204 92798 0 -12.3 -7.321.3 0.06 0 3420 0 240000 91200 0 -11.8 -7.0

Weight = 240000 lbSea level, Std. DayNO ENG = 2

SLOPE=0WIND=0

Spoiler DownCD=.0631CL=.340

Spoiler upCD=.1427CL=-.25

μΒ=0.38


Factors Affecting Stop Calculation

• Airplane Configuration, Drag/Spoiler

• Runway friction capability– Historically FAA AFM is based on dry only

(exception 737 NG - wet runway data in AFM)– Boeing has provided operational data for

non-dry runway– Since 747-400 the JAA has required dry and

slippery data in the AFM

• Assumptions in the transition from go to stop -interpretation and changes in the FAR’s


Effect of Spoilers on Stop – Dry Runway

(W-L)No Spoilers183,460 lb.

(W-L) Spoilers281,570 lb.

DragNo Spoilers10,490 lb.

DragSpoilers23,730 lb. Brake ForceNo Spoilers = 69,720 lb.

Brake ForceSpoilers = 107,000 lb.

Numbers based on previous example calculation at 159 kts

Stopping ForceNo Spoilers = 80,210 lb.Stopping ForceSpoilers = 130,730 lb.


Effect of Spoilers on Stop – Wet Ice Runway

(W-L)No Spoilers183,460 lb.

(W-L) Spoilers281,570 lb.

DragNo Spoilers10,490 lb.

DragSpoilers23,730 lb. Brake ForceNo Spoilers = 9170 lb.

Brake ForceSpoilers = 14,090 lb.

Numbers based on previous example calculation at 159 kts

Stopping ForceNo Spoilers = 19,660 lb.Stopping ForceSpoilers = 37,820 lb.

Airplane braking coefficient of0.05 used to represent wet ice.


Transition from Go to Stop

• Pilot actions - typical flight test times– Brakes on - initial action– Throttles - typically .1 to .3 sec after brakes– Spoilers - typically .5 to .8 after throttles

• Flight test is a measure of time required to physically perform the action

• For AFM, additional time delay is added for the line pilot reaction time



Transition from Go to Stop

• Many different methods have been used over the years

• Written FAR was not always the actual method

• Methods– Distributed time - engine out stop– Constant velocity - engine out stop– Continued acceleration - all engine stop– Constant velocity - all engine stop

continued


Distributed Time Transition Method707, 727, 737-1/2/Adv, 747-1/2/300

Throttle Chop on Operating Eng

Flight Test Demonstration

Eng Fail

Airplane Flight Manual Calculation

Eng Fail

1 s

V1

1 s 1 s

BrakeApplication

SpoilerDeployment


Constant Velocity Transition Method737-300/4/5, 757-200, 767-2/300, 747-400


Eng Fail


SpoilerDeployment


Eng Fail

BrakeApplication

2 s at Constant Velocity

1 s

V1

BrakeApplication


Amend 25-42 Transition Method777, MD-11


Event



Event

2 s All Engine Acceleration

1 sV1

SpoilerDeployment

BrakeApplication


Amend 25-92 Transition Method737-6/7/8/900, 757-300, 767-400


Event



Event

2 s Constant Velocity

1 sV1

SpoilerDeployment

BrakeApplication


Sample Calculation of AFM Stopping Distance - Amend 25-92

Weight = 240000 lbSea level, Std. DayNO ENG = 2

SLOPE=0WIND=0

Spoiler DownCD=.0631CL=.340

Spoiler upCD=.1427CL=-.25

μΒ=0.38

SpindownTC

GroundSpeed

TotalDistanceEvent Time Accel ft/s2 Accel kt/s Distance

V1 0 160 0Brakes on 2 1.00 160 -3.1 -1.8 540 540

Throttle Chop 2.3 1.00 159 -3.1 -1.8 81 6212.5 1.00 159 -3.1 -1.9 53 6742.7 0.99 159 -3.2 -1.9 54 728

Spoilers up 2.701 0.99 159 -9.9 -5.9 0 7283.3 0.64 155 -12.4 -7.4 141 8694.3 0.30 148 -14.5 -8.6 236 11055.3 0.22 139 -14.7 -8.7 241 13466.3 0.18 131 -14.5 -8.6 229 15758.3 0.14 113 -13.9 -8.2 420 199510.3 0.112 97 -13.4 -7.9 362 235712.3 0.092 81 -12.9 -7.7 305 266216.3 0.064 50 -12.3 -7.3 455 311723.3 0.06 0 -11.8 -7.0 302 3419


Distance - Velocity Amend 25-42 and Amend 25-92

0

20

40

60

80

100

120

140

160

180

200

0 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000Distance - Feet

All Engine Acceleration Stop from V1 = 160 Stop from V1=153.7


Accel-stop with 2 sec. No accel/decelAmend. 92

Accel-stop with 2 sec. continued all engine acceleration - Amend. 42

Stop initiated at 160 Stop initiated at 153.7

Note: V1 is 153.7 in both cases


Sample Accel – Stop Calculation

Sample Accel – Stop Calculation

Amend 92 – current method


Sample A-S Distance Calculation

•Amend 92 – current method– Choose V1 speed– Calculate distance to V1

– An event is assumed to have occurred 1 second prior to V1

– The event is not an engine failure so all engine acceleration is assumed between event and V1

• Determine transition to full braking configuration distance

• Determine distance to stop


Sample Calculation - All Engine Distance

(1) Use the earlier developed all engine acceleration data

(2) Assume V1 = VR = 160

SGround AE Brake Release to R = Step integration BR to V1,VR = 5437 feet

ALL ENGINE


0 9.0 5.3 020 8.7 5.2 64 6440 8.4 5.0 199 26460 8.0 4.8 346 61080 7.6 4.5 510 1120100 7.1 4.2 697 1817120 6.6 3.9 917 2734140 6.0 3.5 1183 3917150 5.6 3.3 713 4630160 5.3 3.1 808 5437

020406080100120140150160

Brake Release

VR


8854295-7.0-11.8912002400000342000.0623.3

8559442-7.3-12.39276924412823563648500.06416.3

8117300-7.7-12.99531725083461845245810.09212.3

7816354-7.9-13.49710425553788696385970.11210.3

7462412-8.2-13.9992132610861203678101130.148.3

7050228-8.6-14.510196926833816175101471310.186.3

6822242-8.7-14.610332427190518211123701390.225.3

6580256-8.6-14.610494527617020646171021480.34.3

6324159-7.4-12.410627627967322645361991550.643.3

61650-5.9-10.010706428174723829566641590.992.7Spoilers up6165107-1.9-3.26962518322410537566641590.992.7

605881-1.9-3.169625183224105375672115912.3Throttle chop5977540-1.8-3.169353182508106705700616012Brakes on54370.0069353182508106705700616010V1

accel kt/sAccel ft/s2FBW-LDragTotal ThrustGround SpeedSpindownTime StepDist.

TotalDist.

(3) Determine stopping distance from V1

for this example assume V1 = 160 knotsAll engine Distance to 160 kts

Total distance to accelerate to V1 and stop


0

20

40

60

80

100

120

140

160

180

200

0 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000Distance - Feet

All Engine Acceleration Stop from V1 = 160

V1 =VR= 160 kts

All Engine Acceleration Stop from 160 kts

Accel - Stop with V1 of 160- 8854 ft.


• What happens to the accel – stop distance if V1 is reduced to 152.3 ?


7991241-7.0-11.89120024000103456-0.60.0622.67

7750408-7.2-12.2924922434001941368745.40.06416.3

7342281-7.5-12.7947802494225378529975.50.09212.3

7061335-7.8-13.1964062536997819645291.10.11210.3

6726390-8.0-13.698406258964108258064107.20.148.3

6336216-8.3-14.11008242653271445710369123.80.186.3

6120230-8.4-14.21021782688911649112673132.30.225.3

5890243-8.3-14.11036072726501863717281140.60.34.3

5646151-7.0-11.91048812760022055036866147.70.643.3

54950-5.6-9.41055062776472148957027151.00.992.7Spoilers up

5495102-1.9-3.271744188799950257027151.00.992.7

539377-1.9-3.271550188291959757603151.712.3Throttle chop

5316514-1.9-3.171405187908966857603152.312Brakes on

48020.0071405187908966857603152.310V1

accel kt/sAccel ft/s2FBW-LDragTotal ThrustGround SpeedSpindownTime StepDist.

TotalDist.

(3) Determine stopping distance from V1

for this example assume V1 = 152.3 knots

All engine Distance to 152.3 kts

Total distance to accelerate to V1 and stop


0

20

40

60

80

100

120

140

160

180

200

0 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000

Distance - Feet

Gro

und

Spee

d - k

ts

All Engine Acceleration Stop from V1=152.3

V1 = 152.3 kts

All Engine AccelerationStop from 152.3 kts

Accel - Stop with V1 of 152.3- 7991 ft.




1.15 all engine distance = 8133 feet


V1 = 152.3 then 9755 feet


Accel – Stop distance

V1 = 152.3 then 7991 feet



Other stopping considerations


Sample System for Wheel Braking

Left Wheel Brakes Right Wheel Brakes

System B Return

Normal Brake Metering

Valve

Return Line From Right

Normal Brake Metering Line

Alternate Brake

Metering Valve

Parking Brake Shutoff Valve

Autobrake Shuttle Valve

Brake Pressure Switch

Normal Anti-Skid Valve


Alternate Anti-Skid Valve

Hydraulic Fuse

Hydraulic Fuse

Hydraulic Fuse

To System A

Return

Shuttle Valve

Shuttle Valve



Alternate Anti-Skid Valve

Hydraulic Fuse

Hydraulic Fuse

Hydraulic Fuse

Shuttle Valve

Shuttle Valve

Autobrake Shuttle Valve

Normal Brake Metering

Valve

Alternate Brake

Metering Valve

To System B

Return

Brake Pressure Switch

Autobrake Pressure Module

From Left Alternate Brake Metering Valve and Anti-Skid

Return

Gear “UP”Pressure System AAlternate

Source Selector

Valve

Accumulator Isolation Valve

Accumulator

Alternate System A PressureNormal

System B Pressure

To System A

Return

System B PressureSystem B ReturnSystem A PressureSystem A ReturnGear “UP” Pressure


Wet Runway - Historically

• Historically, FAA AFM did not contain wet runway takeoff performance

• Boeing did do wet runway testing on the 707, 727, 737-1/200, 747-1/200 for British CAA certification

• Conclusion wet runway braking capability about half of dry runway anti-skid limited capability –

PEM recommendation ~ 0.2 airplane braking coefficient


Brake Force Generalization - Wet

FB ,BrakeForce

W - LAverage Weight

on Wheels

WVΒg2




Dry

Wet runway performance - Maximum manual braking

Wet ~ ½ dry or ~ 0.2 airplane braking coefficient


New (1998) FAR Wet Runway Rule – Amend 25-92

• Reference 25.109 (c)

• Manufacturer adjusts an industry standard (ESDU) wet runway curve up and down to account for individual airplane’s anti-skid efficiency– Adjustment based on airplane wet runway anti-

skid tuning test data

• Wet and Wet skid-resistant runway surfaces may be considered– Grooved or porous friction course


New FAR Wet Runway Rule

Sample wet runway data for FAR 25.109 ( c ) as amended by Amendment 25-92 in 1998

Note: values will vary from airplane to airplane

0

0.1

0.2

0.3

0.4

0.5

0 50 100 150 200 250Ground Speed

Airplane Braking Coefficient

Individual airplane may be higher or lower based on the anti-skid of that airplane.

Wet Runway

Wet Skid-resistent


Boeing Slippery Runway Data

• Constant Airplane Braking Coefficient -μΒ = 0.20, 0.15, 0.10, 0.05

• Intent of data is to provide the airline the ability to chose the data level which best fits their operation

• Method came as a result of industry meeting in the early 80’s– Airline input - we know more about the runways

we operate on than you do, give us a method that allows us some flexibility


Boeing OM Slippery Runway Data

• μΒ = 0.2 Good– Approximately 1/2 dry anti-skid limited braking

capability – recommended for wet runway where AFM does not contain certified wet runway performance

– JAR certification for compact snow

• μΒ = 0.1 Medium– Limited 727 compact snow and ice data from the

60’s at -7 to -10 C resulted in μB = 0.08 to 0.14

• μΒ = 0.05 Poor– Wet ice

continued


Other Stopping Considerations

• Reverse Thrust– Re-direction of engine airflow to provide an

effective stopping force– No credit is used in calculation of dry runway AFM

performance– Credit is typically used for non-dry runway

advisory data (wet, slippery)– Current (1998 on) FAA certifications take credit

for reverse thrust for wet runway AFM data


Stowed

Unlocked

Reverse

Translating SleeveBlocker Door

Rev

Rev

Green

Amber

Drag LinkFixed Cascade Vanes

Air Flow


Thrust Spindown / Reverse Spinup

-20000

-15000

-10000

-5000

0

5000

10000

15000

20000

25000

30000

35000

0 2 4 6 8 10 12 14 16

Time from Brake Application - Sec

Thrust - lb Idle

Reverse

Example Only


Brake Energy

Brake Energy Considerations


Brake Anatomy

• Brake assembly composed of rotors, stators, hydraulic pistons and a pressure plate

• Rotors, stators alternate to form “heat stack”


Brake Application


2

21

Gaircraft Vm

Brakes As Energy Converters

• Kinetic Energy Heat EnergyHeat Energy

Where m = mass,VG = groundspeedc = specific heat of heat sink materialT = temperature

Reverse Thrust

Aerodynamic Drag

TcmheatsinkΔ


2

21 Vm aircraft

Worn Brakes

“Heat sink” mass (i.e. mass of rotors and stators) may decrease by up to 30% at fully worn limit

Brake energy performance is directly related to heat sink available.

Prior to 1988, no requirement in airworthiness standards to demonstrate stopping capability or energy absorption with worn brakes…

Kinetic Energy Heat Energy

TcmheatsinkΔ


Certification Requirements

The most important of these energy levels are:

• Maximum kinetic energy accel-stop

• Most severe landing stop

• Fuse-plug-no-melt stop

Brake Energy

As part of the certification process, brakes are subjected to a multitude of dynamometer and flight tests that establish, among other things their ability to safely absorb and dissipate high energy levels


Certification Requirements

Energy associated with a Rejected Takeoff (RTO):• Most critical combination of altitude, temperature,

takeoff weight, speed• Dynamometer test substantiates wheel, brake and

tire can safely absorb this energy• For newer airplanes, dynamometer test is

conducted with 100% worn brakes

Maximum Kinetic Energy Accelerate-Stop


Worn Brakes - History

• Flaps/slats were in normal symmetrical configuration, erroneous warning due to out-of-tolerance position sensor

• Of 10 brakes, 2 were essentially new, and functioned normally

• Remaining 8 brakes were at or near wear limit, and failed during RTO

DC-10 Accident, Post-crash Investigation

Accident investigation revealed that the maximum level of energy that brakes can safely absorb is reduced as brakes wear…

• This reduction in capacity contributed to the brake failures during the stop


Worn Brakes - History

• FAA Airworthiness Directives imposed revised wear pin limits for all in-service jet transports with MTOW > 34,000 kg, to address brake energy issue

And Regulatory Activity – In-service airplanes


Worn Brakes

All airplanes certified after adoption of Amendment 25-92 (20 March 1998) include full worn brake accountability at the time of certification. The following Boeing airplanes meet this revised standard:

737-600/-700/-800/-900757-300767-400777 (all)MD-90717MD-11

And New Airplane Certification


Certification Requirements – Brake Energy

Regulations also require an RTO demonstration to validate the dynamometer test results:

• Recent revision to regulations requires that this flight test is conducted with 90% worn brakes

• For 5 minutes after completion of the stop, no condition can jeopardize safe and complete evacuation

Maximum K.E. Accel-Stop: Flight Test


Certification Requirements – Brake Energy

Maximum K.E. Accel-Stop: Flight Test


Dispatch Requirement:

• Once the Maximum Kinetic Energy Accel-Stop is established, this defines the brake energy limitation that must be evaluated for every takeoff

Maximum Kinetic Energy Accelerate-Stop

• May restrict maximum V1 selection (VMBE)

• In more severe cases, may limit allowable takeoff weight

Brake energy is typically limiting in high/moderately hot conditions, on long runways, with less deflected takeoff flap settings…


Certification Requirements – Fuse Plugs

• FAR/JAR Part 25 requires overtemperature burst protection for wheels and tires

• Fuse plugs are installed typically in inner wheel halves

• They melt at a precise temperature and deflate tire

• Fuse plugs must demonstrate their intended function:– They must melt and safely release tire pressure at an

energy in excess of Fuse-plug-no-melt energy– Typically demonstrated in conjunction with Maximum

Kinetic Energy Accel-Stop flight test RTO

Overtemperature Burst Protection

And Maximum Kinetic Energy Accel-Stop


Fuse Plugs

And Maximum Kinetic Energy Accel-Stop


Regulatory Limit

Intent: To ensure that no takeoff is scheduled such that RTO would exceed the certified energy absorption capability of the brakes

VMBE and Max Brake Energy for Takeoff

Assumptions:

• Maximum braking

• No credit for reverse thrust

• Accountability for worn brakes…

• Residual brake energy equivalent to three miles taxi, three taxi stops prior to RTO initiation


Regulatory Limit

Application:

• Do not schedule takeoff with V1 that exceeds VMBE

• May restrict takeoff weight

• Unbalanced (lower) V1 may avoid or minimize weight offload

VMBE and Max Brake Energy for Takeoff

Note:

• Brakes are assumed to be essentially cool prior to RTO initiation…3 taxi stops in test


Sample Brake Energy Calculation

SpindownTC

GroundSpeed

Brake Energy - 106

Event Time Accel ft/s2 Accel kt/s Distance FB Step Sum

V1 0 160 0Brakes on 2 1.00 160 -3.1 -1.8 540 0.0 0.0

Throttle Chop 2.3 1.00 159 -3.1 -1.8 81 69514 5.6 5.62.5 1.00 159 -3.1 -1.9 53 69614 3.7 9.32.7 0.99 159 -3.2 -1.9 54 69715 3.7 13.1

Spoilers up 2.701 0.99 159 -9.9 -5.9 0 106998 0.0 13.13.3 0.64 155 -12.4 -7.4 141 106303 15.0 28.04.3 0.30 148 -14.5 -8.6 236 104902 24.7 52.85.3 0.22 139 -14.7 -8.7 241 103351 24.9 77.76.3 0.18 131 -14.5 -8.6 229 101882 23.3 101.18.3 0.14 113 -13.9 -8.2 420 99261 41.7 142.710.3 0.112 97 -13.4 -7.9 362 97090 35.1 177.912.3 0.092 81 -12.9 -7.7 305 95323 29.1 207.016.3 0.064 50 -12.3 -7.3 455 92798 42.2 249.223.3 0.06 0 -11.8 -7.0 302 91200 27.5 276.7

Higher brakes on speed, weight - greater brake energy

TP, Page 213

FLIGHTOPERATIONS

ENGINEERING


Field Length Considerations


§ 121.189 Airplanes: Turbine Engine Powered: Takeoff Limitations

(c) No person operating a turbine engine powered airplane …. may take off that airplane at a weight greater than that listed in the Airplane Flight Manual at which compliance with the following may be shown:


§ 121.189 Airplanes: Turbine Engine Powered: Takeoff Limitations

(c) continued ...

(1) The accelerate-stop distance must not exceed the length of the runway plus the length of any stopway.

(2) The takeoff distance must not exceed the length of the runway plus the length of any clearway except that the length of any clearway included must not be greater than one-half the length of the runway.

(3) The takeoff run must not be greater than the length of the runway.


Accelerate - StopVEvent

V1

All engineacceleration

1 Second

V Full Braking Configuration

Maximummanual braking

Transition

15%

All Engines operating throughout the takeoff35 feet, V35 AE climb out speed

VLOVRAll engine

acceleration

Engine failure during the takeoff roll 35 feet, V2VEF

V1 VR VLOAll engine


Takeoff Distance


Takeoff Field Length Required

• Longest of distance required for:– Accelerate-Stop Maneuver– Engine inoperative Accelerate-go Maneuver– 1.15 times the All Engine Distance to 35 feet

• Calculation of 1.15 All Engine Distance is very straight forward – demonstrated earlier

• Calculation of A-S distance and EI A-G distance is based on choice of V1 speed – demonstrated earlier




1.15 all engine distance = 8133 feet


V1 = 152.3 then 9755 feet


Accel – Stop distance

V1 = 152.3 then 7991 feet



Field Length Build Up

• Do problem 11 which answers the following questions.

1. What is the legal field length if V1 = 152.3 kts?

2. What is the legal field length if V1 = 160 kts ?

3. What is the minimum legal field length that can be scheduled based on the A-G, A-S and 1.15 All Engine distance on the previous slides? What is the V1 speed for this minimum legal field length? (Hint, you may want to use the graph paper on the next slide


Field Length "X" Plot

7000

7500

8000

8500

9000

9500

10000

150 155 160 165

Choice of V1 Speed - kts.

Dis

tanc

e - F

eet

Eng. Inop. Accel-Go Accel-Stop 1.15 All Engine Distance Rotation Speed

1.15 AE Dist.Accel-Stop

Eng Inop Accel-Go

VR = 160

WeightAltitudeTemperatureFlap


Field Length "X" Plot

7000

7500

8000

8500

9000

9500

10000

150 155 160 165

Choice of V1 Speed - kts.

Dis

tanc

e - F

eet

Eng. Inop. Accel-Go Accel-Stop 1.15 All Engine Distance Rotation Speed

1.15 AE Dist.Accel-Stop

Eng Inop Accel-Go

VR = 160

WeightAltitudeTemperatureFlap

Balanced field length

Balanced V1


Effect on Field Length


Effect on Field Length

• Looked at how the field length is calculated for a single weight.

• Now look at examples as a function of weight


Speed Constraints on V1 as a Function of Weight

Takeoff Speeds

80

90

100

110

120

130

140

150

160

170

180

190

200

210

220

40000 50000 60000 70000 80000 90000 100000

Weight - kg

Spee

d - k

ias

Max. V1=VMBE

Min. V1=V1MCG

Rotation Speed - VR

Flaps 1 Sea Level 15 C


V1 Calculation

• Calculate the “balanced” V1 and see if it is constrained


V1 CalculationTakeoff Speeds

8090

100110

120130140150160170180

190200210220

40000 50000 60000 70000 80000 90000 100000

Weight - kg

Spee

d - k

ias

Max. V1=VMBE

Min. V1=V1MCG

Rotation Speed - VR


Balanced V1


V1MCG and VMBE ConstraintsTakeoff Speeds

8090

100110

120130140150160170180

190200210220

40000 50000 60000 70000 80000 90000 100000

Weight - kg

Spee

d - k

ias

Max. V1=VMBE

Min. V1=V1MCG

Rotation Speed - VR


Balanced V1


Field Length Calculation

• Now plot field length as a function of weight based on the balanced or constrained V1


Field Length ComparisionTakeoff Distance

3000

4000

5000

6000

7000

8000

9000

10000

40000 50000 60000 70000 80000 90000

Weight - kg

Dis

tanc

e - f

t

1.15 AE Distance

Flaps 1 Sea Level 15 C Dry Runway

Balance Limited

V1 = VR limited

V1 = VMBE


What Would Affect Required Field Length?

• Flap – How does that affect the calculation ?

• Altitude, temperature - How does that affect the calculation ?

• Runway surface - wet runway, icy, contaminated

• Equipment - credit for reverse thrust, Anti-skid inoperative, brake deactivated


Flaps 5 vs. Flaps 1Takeoff Speeds

80

90

100

110

120

130

140

150

160

170

180

190

200

210

220

40000 50000 60000 70000 80000 90000 100000

Weight - kg

Spee

d - k

ias

Max. V1=VMBE

Min. V1=V1MCG

Rotation Speed - VR


Flaps 5 data with small dashes (dots)


Effect of Flap - Lower Flap SettingGiven Weight, Altitude, Temp

1.15 AELonger/higher VR, V2 1.15 AE distance

EI A-G distance

A-S distanceDistance

Choice of V1

Less deflected flap - shorter accel-stopLess drag on accel, more weight on wheels on stopSmall Difference

Less deflected flap - Longer accel-goHigher VR, V2


Rebalanced V1Takeoff Speeds

8090

100110120130140150

160170180190200210220

40000 50000 60000 70000 80000 90000 100000

Weight - kg

Spee

d - k

ias

Max. V1=VMBE

Min. V1=V1MCG

Rotation Speed - VR


Flaps 5 data with small dashes (dots)

V1 in Red


Effect of Flap - Lower Flap SettingTakeoff Distance

3000

4000

5000

6000

7000

8000

9000

10000

40000 50000 60000 70000 80000 90000

Weight - kg

Spee

d - k

ias

Sea Level 15 C Dry Runway

Flaps 1 Critical Field length

Flaps 5 Critical Field length

Dis

tanc

e -f

eet



• Flap – How does that effect the calculation ?





Altitude-Temperature Effect – Basic TO SpeedsTakeoff Speeds

80

90

100

110

120

130

140

150

160

170

180

190

200

210

220

40000 50000 60000 70000 80000 90000 100000

Weight - kg

Spee

d - k

ias

Max. V1=VMBE

Min. V1=V1MCG

Rotation Speed - VR


Dashed Lines Based on:Altitude = 5000 feetTemperature - 30 C

V1 Speed


Altitude-Temperature Effect – Field LengthTakeoff Distance

3000

4000

5000

6000

7000

8000

9000

10000

11000

12000

13000

14000

15000

40000 50000 60000 70000 80000 90000

Weight - kg

Dis

tanc

e -

ft

Flaps 1, Dry Runway, no consideration of

SL, 15C Critical Field length

5000 feet, 30C Critical Field length

1.15 AE Distance

Balance Limited

V1 = VMBE



• Flap – How does that effect the calculation ?






Effect of Slippery RunwayGiven Weight, Altitude, Temp, Flap

A-S distance

EI A-G distance

Distance

Choice of V1

Slippery runway - Longer accel-stopBut credit for reverse thrust and rebalanced V1minimizes effect of slippery runway

Slippery runway - No change in accel-go exceptlower screen height, 15 foot not 35 foot

Slippery runwayNo change in 1.15 AE

1.15 AE distance


Effect of Wet (Amend 25-92) / SlipperyTakeoff Speeds

80

90

100

110

120

130

140

150

160

170

180

190

200

210

220

40000 50000 60000 70000 80000 90000 100000

Weight - kg

Spee

d - k

ias

Max. V1=VMBE

Min. V1=V1MCG

Rotation Speed - VR


Balanced V1

Wet Balanced V1

μB=0.05, "wet ice"


Wet (Amend 25-92) / Slippery RunwayTakeoff Distance

3000

4000

5000

6000

7000

8000

9000

10000

11000

12000

40000 50000 60000 70000 80000 90000

Weight - kg

Spee

d - k

ias


FAR Dry Runway Length

Wet RunwayμB=0.05, "wet ice"

Dis

tanc

e -f

eet


• Do Problem 12 in the workbook.

Determine takeoff weight with and without reverse on a slippery runway.








“WET SNOW, 10MM, BRAKING ACTION MEDIUM, TEMPERATURE -10 DEG C”


a = [Thrust - Drag - Friction - Slush DragSlush Drag]gW

Slush DragSlush Drag

Friction Drag Thrust

Acceleration With Slush/Standing Water


FSlush = 1/2 ρ V2g CD Slush ATire

ρ = Slush density, 1.65 slugs/ft3

Equal to specific gravity of 0.85

Vg = Ground speed - Feet per second

CD Slush = Slush drag coefficient for airplane's specific gear arrangement

ATire = Reference area for slush force calculation

Data Sources: FAA/NACA Convair 880 Tests 1962NASA Langley Load Track Tests - 1960,1962


Displacement dragFWD

Impingement dragFWD

CD Accounts for Displacement and Impingement SlushSlush


Ground Speed

Slush force

Slush Force

VHP

HydroplaningHydroplaning


Tire pressure - Evaluated for main gear, psiSlush specific gravity - 0.85

VHP = 8.63Tire Pressure − psi

Specific Gravity

Hydroplaning

Newer Airplanes VHP = 8.63 Tire Pressure − psi


Slush Force Including Hydroplaning

FS = (1/2 ρ CD Vg ATire) x fHPSlush2

VHPGround speed

Slush force

This factor is applied at speeds above the hydroplaning speed.

⎟⎟⎠

⎞⎜⎜⎝

⎛−

⎥⎦

⎤⎢⎣

⎡ −=

5.1HPV

gV5.2

HP

gHPHP V6.

VV6.1f


VHPGround speed

Slush force

VR VLOF

Slush Force From Rotation to Liftoff

FS = (1/2 ρ CD Vg ATire) x fHP x fR x fLOFSlush2


Ground Speed

Airplane Acceleration Forces

All engine thrust

Engine out thrust

VHP VR VLOF

Force Variation With Speed

Total Acceleration Force = Thrust - (Slush force + Aero drag + Friction)


6 mm of slush - 10-20 % reduction in all engine acceleration13 mm of slush - 20-40 % reduction in all engine acceleration

All Engine Acceleration Capability130 Knots

4.0

3.0

2.0

1.0

0.0

All engine acceleration Kt/sec

Dry6 mm

13 mm

747 767 757 737

Dry6 mm

13 mm

Dry6 mm

13 mm

Dry

6 mm13 mm


7470.0

1.0

2.0

3.0

4.0

6 mm13 mm

Dry all engine

-0.5

Engine outDry

767 757 737

6 mm13 mm

Engine out

Dry6 mm

13 mm

Engine out

Dry

6 mm13 mm

Engine out

Dry

Dry all engine

Dry all engine Dry all

engine

Acceleration Kt/sec

130 KnotsEngine Out Acceleration Capability

6 mm of slush - 15-50 % reduction in engine out acceleration13 mm of slush - 30-110 % reduction in engine out acceleration


Effect of Slush On Airplane Stopping

• Tire to ground friction reduced due to slush

• Retarding slush drag acts to slow the airplane

Dry runwayAverage brake force

0.9VhpGround Speed, Knots

Retarding Force

Vhp

Slush drag

Total Slush stopping force = Slush Drag + Wheel braking

Slush wheel baking


• Dry - AFM performance - includes maximum braking, spoilers, idle thrust

• Slush - includes wheel braking, spoilers, reverse thrust, and slush drag

One Engine Inoperative Deceleration Capability130 Knots

Deceleration Kt/sec

Dry

6 mm13 mm

Dry

6 mm

13 mm

Dry

6 mm

13 mm

Dry

6 mm13 mm

8.0

6.0

4.0

2.0

0.0747 767 757 737


Effect of Contaminated RunwayGiven Weight, Altitude, Temp, Flap

A-S distance

EI A-G distance

Contaminated runwayLonger 1.15 AE distance

1.15 AE distance

Distance

Choice of V1


Contaminated runway - accel-go distance is longer except lower screen height, 15 foot not 35 foot minimizes effect


A-S distance

EI A-G distance


1.15 AE distance

Distance

Choice of V1


Contaminated runway - accel-go distance is longer except lower screen height, 15 foot not 35 foot minimizes effect


A-S distance

EI A-G distance


1.15 AE distance

Contaminated runway - Longer accel-stopBut credit for reverse thrust and rebalanced V1minimizes effect of contaminated runway

Distance

Choice of V1


Contaminated Runway Takeoff SpeedsTakeoff Speeds

8090

100110120130140150160170180190200210220

40000 50000 60000 70000 80000 90000 100000

Weight - kg

Spee

d - k

ias

Max. V1=VMBE

Min. V1=V1MCG

Rotation Speed - VR


Balanced V1

12.7 mm SW

3 mm SW


Contaminated Runway Field Length TradeTakeoff Distance

3000

4000

5000

6000

7000

8000

9000

10000

11000

12000

13000

14000

15000

40000 50000 60000 70000 80000 90000

Weight - kg

Spee

d - k

ias



3 mm SW

12.7 mm SW








Takeoff Distance

3000

4000

5000

6000

7000

8000

9000

10000

11000

12000

13000

14000

15000

40000 50000 60000 70000 80000 90000

Weight - kg

Spee

d - k

ias

Flaps 1 Sea Level 15 C Dry Runway


AS inopFull Rate

AS Inop Derate 2

Dis

tanc

e -f

eet


All Engine Limited Airplanes

“Typically” 3 and 4 engine airplanes are limited by the 1.15 AE criteria (twins are “typically” limited by balance considerations)

We did see an example of where a twin was 1.15 AE limited


All Engine Limited AirplanesGiven Weight, Altitude, Temp

EI A-G distance

1.15 AE distanceDistance A-S distance

Min V1 Max V1


Other Considerations That Limit Takeoff Weight


Other Takeoff Weight Considerations

• Field Length– Wind/Slope– Clearway/Stopway– Inoperative/Missing Equipment - MMEL/CDL

• Tire Speed

• Climb

• Obstacle

• Brake Energy




Field Length - Slope

• Uphill slope helps stop part

• Uphill slope hurts acceleration

• What slope should be used for this runway ?

• How about this one ?


Field Length - Wind

• Wind parallel to the runway

• Wind measured at the “tower” height– Older FAA - 50 feet assumption– Newer FAA/JAR/CAA - 10 meters– Adjusted to mean aerodynamic chord height– WMAC = (hMAC/hTower)1/7

• Credit for 50 % of reported headwind, penalized for 150 % of reported tailwind

• Maximum tailwind 10/15 knots


Crosswind

• Airplane controllability issue

• AFM provides maximum demonstrated crosswind, not limiting

• Flight Crew Training Manual and/or Operations Manual contain recommended values for different runway conditions.– Considerations - engine failure, aft c. g., “normal”

piloting skill


Example from 737


Field Length - Clearway / Stopway

Clearway/Stopway can be used to increase takeoff weight

200 feet(61 m)(Typ)

Stopway

At least aswide as runway

500 feet(152.4 m)minimum

Clearway


Clearway

• Clearway is the area beyond the runway. It must:– At least 500 feet (152.4 m) wide– Have its center on the same line that is the extended

center line of the runway– Be under the control of the airport authorities– No object or terrain in the clearway may project

above a +1.25% plane.

• Clearway credit is allowed for no more than half of the air distance. The air distance is the distance between lift-off and the point where the airplane is 35 feet (10.7 m) above the ground.


VR VLO

VLOVR

35 feet, V35 AE climb out speed

V1 35 feet, V2

Maximum Allowable Clearway

Air distance

1/2 air distance

1.15 x air distance

1/2 1.15 x air distance

15%

All Engines operating throughout the takeoff

All engineacceleration

Engine failure during the takeoff roll


Stopway

• Stopway is an area beyond the runway. It must:– Be at least as wide as the runway– Have its center on the same line that is the extended

center line of the runway– Be identified for use to decelerate an airplane if that

airplane does a rejected takeoff– Have the capacity to hold the airplane without causing

any structural damage during a refused takeoff.


• Go to Problem 13 in workbook

Review of Clearway / Stopway data


Lineup Allowance

• Allowance to account for airplane turning onto the runway

• 90 and 180 degree lineup allowances in RTO training aid and FPPM

L, Page 54


Inoperative Equipment, MMEL, CDL

• Inoperative Equipment can effect takeoff field length performance– Anything that affects drag, lift, stall speed, engine

thrust (bleed), and braking efficiency can effect the performance

– Examples:– Brakes - Anti-skid inoperative, brake deactivated– Slat/flap seals - stall speeds


Other Takeoff Weight Considerations

• Tire Speed - Maximum rotational velocity of the tire. Limited by the airplane’s maximum velocity on the ground, VLOF

• Climb - Maximum weight which meets the FAA climb gradient requirements for that flap - to be discussed later

• Obstacle - To be discussed with Climb

• Brake Energy - Limit on V1 as discussed earlier


Sample Field Length - Gross Weight Plot

FieldLengthRequired

Brake Release Gross Weight

V1mcg limit

15

5

1Climb weight limitations

Brakeenergylimitation

Tire speed Limit - 210 mph

Tire speed limit -225 mph


9. True or False, V2 is determined by the airplane’s stall speed.

10. True or False, there is one and only one unique V1speed that meets the regulatory requirements for any given takeoff.

False, airplane stall speed is only one factor checked when establishing the V2 speed. Other considerations include the minimum unstick, minimum control speed, minimum tail clearance and climb requirements.

False, there are multiple speeds which can meet the FAR requirements, but there are certainly cases where weight optimization results in a single V1 value required to satisfy the FAR’s for that specific optimized takeoff weight and conditions.


False, there are multiple speeds which can meet the FAR requirements, but there are certainly cases where weight optimization results in a single VR value required to satisfy the FAR’s for that specific optimized takeoff weight and conditions.

False, there are multiple speeds which can meet the FAR requirements, but there are certainly cases where weight optimization results in a single V2 value required to satisfy the FAR’s for that specific optimized takeoff weight and conditions.

11. True or False, there is one and only one unique VR speed that meets the regulatory requirements for any given takeoff.

12. True or False, there is one and only one unique V2 speed that meets the regulatory requirements for any given takeoff.


13. True or False, Boeing, Douglas and Airbus use the same philosophy when determining the “standard”takeoff speeds.

14. True or False, Boeing, Douglas and Airbus use the same philosophy when determining the “optimum”takeoff speeds.

False, Boeing typically uses a minimum takeoff speed philosophy to always favor a minimum field length , Douglas uses dial-a-flap concept on the MD-80 and MD-11 which is biased towards the lowest possible takeoff speeds at more deflected flap settings and towards the best climb gradient takeoff speeds at less deflected flap settings.

False, in general yes, but the way they get there is different.


Jump to 81 Climb.ppt

15. True or False, all Boeing airplanes have performed flight test to determine the airplanes stopping capability on a wet runway.

False, many models did not perform wet runway stopping tests but rather have used estimates based on other models tested.

CP, Page 1

FLIGHTOPERATIONS

ENGINEERING


Climb Physics

CP, Page 2For Training Purposes Only Copyright © 2009 Boeing. All rights reserved

Climb

• To discuss climb we must first define terms used in describing climb.– Angle of attack (α), flight path angle (γ), pitch

attitude (θ), rate of climb( )dhdt


Climb Angles

aB - body angle of attack

θ - pitch attitude - αB + γ

γ - flight path angle

Vγ

αΒ θ


Climb Vectors

V - true airspeed

Vg - ground speed = V Cos γ - VW

R/C - rate of climb = dhdt

Vγ R/C =

V Cos γVW

dhdt


R/C Vector - Vertical Speed

Gradient = Opposite / Adjacent = Tan of the angle

Vγ R/C

V Cos γ

R/C - rate of climb = R/C = V Sin γ

Tan γ =Sin γCos γ

R/CV Cos γ

=


Axis system• Parallel and perpendicular

to the direction of flight

Climb Free Body Diagram

( )

T

γ

Wγ

W Sin γ

dγdtm V

L

D

( )dVdt

Wg

W Cos γ


Climb Equations

Forces perpendicular to the flight path

• Derivation of gradient / rate of climb equations

Forces parallel to the flight path

ΣF = T – D – W sin γ – m = 0dVdt

ΣF = L – W Cos γ + m = 0V dγdt


Climb Equations

• Parallel Forces

W sin γ = T – D – m dVdt

T – D – W sin γ – m = 0dVdt

Wgm =

continued

W sin γ = T – D – dVdt

Wg


Divide through by W

At this point in college, our professors would say:

Climb Equations

Remember: R/C = V Sin γ

Sin γ =R/CV

continued

W sin γ = T – D – M Wg

dVdt

Sin γ = DW

1 dVg dt

TW – –


Substituting for Sin γ

If the airplane flies at constant true airspeed then:

Climb Equations

dVdt = 0 T – D

W VR/C =

Do we ever fly at constant true airspeed ?

continued

V dVg dt

T – DW VR/C = –

= TW

DW

1 dVg dt

R/CV

– –


Climb Equations

• Typically airplanes fly at a constant indicated (calibrated) airspeed or constant mach numbers.

• As altitude changes during the climb, true airspeed will change due to the change of temperature, pressure and density.

• At constant indicated, the true airspeed will increase during the climb.

• At constant mach number(below the tropopause), the true airspeed will decrease during the climb.

continued


Climb Equations

Need to determine how to account for acceleration effect.

continued

Tropopause

True Airspeed, V

Constant VI , VC

Constant Mach Numbers

True Altitude


Consider the following:

Climb Equations

Also consider:

dVdt = dV

dhdhdt

Substitute

continued

R/C = dhdt = T-D

W V –V dVg dt

= T - DW

VgVdh

dtdVdh

dhdt−


A little algebra:

Climb Equations

= Vg

T - DW Vdh

dtdVdh

dhdt+

continued

= T - DW Vdh

dt ( )Vg

dVdh1 +

= = R/Cdhdt ( )V

gdVdh1 +

T - DW V


Climb Equations

R/C =

T - DW V

( )Vg

dVdh1 +

=

T - DW V

AccelerationFactor

Constant Mach NumbersTropopause

True Airspeed, V

Constant VI, VC

True Altitude

ΔV

Δh

continued


Acceleration Factor

• Acceleration factor is a function of:

– How the airplane is being flown– Constant CAS, EAS, TAS– Constant M

– Temperature– ISA (standard day) or non-ISA

– Altitude– Above / below the tropopause

( )Vg

dVdh1 +


Acceleration Factor

Reference: 3.141 - 3.143 of Jet Transport Performance Methods, D6-1420

Temperature ConstantSpeed

BelowTropopause

AboveTropopause

Standard

NonStandard

M 1 − 0.133184 M2 1

VE 1 + 0.566816 M2 1 + .7 M2

VC 1 + .7 M2 (φ − .190263) 1 + .7 M2 (φ)

M 1 − 0.133184 M2 1

VE 1 + .7 M21 + .7 M2 [1 − .190263 ]( )Tstd

T

( )Vg

dVdh1 +

φ =1 [(1 + 0.2 M2)3.5 − 1]0.7M2 (1 + 0.2 M2)2.5

VC 1 + .7 M2 (φ)1 + .7 M2 [φ − .190263 ]( )Tstd

T


Acceleration Factor Constant VC

Standard Day

1.000

1.100

1.200

1.300

1.400

100 150 200 250 300 350Calibrated Airspeed

1+v/g(dv/dh) Constant Vc

25000

360893500030000

2000015000100005000

Acceleration Factor ( )Vg

dVdh1 +

Can Be Found in PEM and D6-1420


Climb Free Body Diagram

( )

T

γ

Wγ

W Sin γ

dγdt V

L

D

( )dVdt

Wg

W Cos γ

Axis system• Parallel and perpendicular

to the direction of flight

Wg


Climb Equations


• Derivation of gradient / rate of climb equations

Forces parallel to the flight path

ΣF = T – D – W sin γ – M = 0dVdt

ΣF = L – W Cos γ + M = 0V dγdt


Climb Equations


V dγdt

Acceleration due to changing flight path angle with respect to time.

Acceptably small to be considered zero.

Equation simplifies to: L = W Cos γ

For hand calculations it is typically assumed that the Cos γ is 1, therefore: L = W

L − W Cos γ = − M V dγdt

continued


Climb Equations

Algebra and substitution

L = W( )

T − DW V

Vg

dVdh1 +

R/C =

How is rate of climb maximized?

Vg

dVdh1 +

Vg

dVdh1 +

( )T DW W V

R/C = ≅− ( )T D

W L* V−

( ) ( )* Note:

assumption that L = W is precise only for small

angles


Climb Equations

How is gradient maximized?

Remember from the earlier discussionGradient = Tan of the angle

( )Vg

dVdh

1 +

( )T DW W =

( )Vg

dVdh

1 +

T DW L( )

Gradient = Tan γ = Sin γ =~


Workbook Problem

• Do problem 14 in the performance workbook. – Calculate the all engine gradient and rate of

climb for the provided conditions


Gradient Capability

0.06000.07000.08000.09000.10000.11000.12000.13000.14000.15000.1600

170 175 180 185 190 195 200Velocity Vc

Gradient

767

747

747 and 767 PW4056 data representative performancelimited weights.

V2 + 10

V2 + 15

All engine, Takeoff Flaps


1500.0

2000.0

2500.0

3000.0

170 175 180 185 190 195 200Velocity Vc

Rate of Climb - Ft/min

767

747

747 and 767 PW4056 data at representative performance limited weights.

V2 + 10

Rate of Climb Capability

V2 + 15

All engine, Takeoff Flaps


Engine Inoperative Climb Performance and Other Considerations


Engine Inoperative Climb

• What changes in the climb calculation when an engine has failed?– Thrust– Drag


Engine Inoperative Climb

Failed engine

AdditionalDrag

• Asymmetric thrust• Yaw• Trim to zero wheel

CORRECT (Recommended)Control wheel approximately level, slip/skid indicator slightly out, rudder as required

Moment due to engine

Moment due to rudder to

trim out enginemoment


Engine Inoperative Climb Gradient

DEO = DAE + ΔDWM + ΔDControl ψ

( )( )V

gdVdh1 +

T − DAE − ΔDWM+Control

W~GradientEO = Tan γ = Sin γ =

( )T DEOW L~GradientEO = Tan γ = Sin γ =

( )Vg

dVdh1 +


Engine Inoperative Drag

• Two parts– Engine drag (windmilling)– Control (trim to wheel level, mostly yaw)

• Flight test to determine engine out contribution– Fly all engine drag, fly engine out drag– Subtract to determine ΔDWM+Control

– Use engine manufacturer data to determine windmill drag contribution

– Left over is control drag


Control Drag

• Control Drag is the additional drag resulting from flight control deflection required to trim the airplane

• Generalized as a function of yawing moment coefficient - CN

CN =(Fn + DWM) le

q S b


Windmill Drag − 7G7 − Δ CDWM = 0.0010 (all Machs)

0

500

1000

1500

2000

0 0.2 0.4 0.6 0.8 1Mach No.

Drag/Delta

Control Drag - 7G7

00.0010.0020.0030.0040.0050.006

0 0.01 0.02 0.03 0.04 0.05CN - Yawing Moment Coefficient

ΔCDψ


Workbook Problem

• Do problem 15 in the performance workbook.– Calculate the engine inoperative gradient and

rate of climb for the provided conditions

• Do problem 16 in the performance workbook.– Calculate the engine inoperative gradient and rate of

climb for the provided conditions – Improved Climb


Gradient Capability

0.0000

0.0200

0.0400

0.0600

160 165 170 175 180 185 190Velocity VC

Gradient

747 and 767PW4056 data at representative performance limited weights.

767

747

V2

Engine Inoperative, Takeoff Flaps


Rate of Climb Capability

400

500

600

700

800

900

160 165 170 175 180 185 190Velocity Vc

Rate of Climb, Ft/min 747 and 767

PW4056 dataat representative performance limited weights.

767

747

Engine Inoperative, Takeoff Flaps


0

0.02

0.04

0.06

0.08

0.1

0.12

0.14

0.16

160 165 170 175 180 185 190Velocity Vc

Gradient

767 All Engine

747 All Engine

V2 + 15

V2 + 10

747 and 767 PW4056 data at representative performance limited weights.

747 Engine Inoperative

767 Engine InoperativeV2

Gradient Capability


Acceleration Capability

• So far we have discussed the airplane’s ability to climb at a constant speed.

• Another consideration is the airplane’s ability to accelerate.

• Climb/acceleration trade

• Consider the following:

ΣF = T − D − W sin γ − = 0WdVg dt

Sin γ = TW

DW

dVg dt− −



Small angle approximation:

Unaccelerated flight - constant true airspeed:

dVdt = 0

Define term gradient available as:

Sin γ = TW

DW

1 dVg dt− −

γ = TW

DL

1 dVg dt− −

γavailable = TW

DL−



Substitute back into small angle gradient equation :

Gradient (energy) available can be traded for climb or acceleration

or

agγavailable = γ +

γ = γavailable − agag

1 dVg dtγ = γavailable −


Workbook Problem

• Do problem 17 in the performance workbook.– Calculate the engine inoperative and all engine

acceleration capability for the conditions of problem 14, 15.



• The inflight acceleration/climb trade is used when determining the flap retraction distance and procedures.– Flap retraction is a function of time– The airplane must accelerate fast enough that

adequate safety margin to stall is maintained– Engine inoperative consideration

– The airplane must not accelerate so fast that flap placard speed at the next flap is exceeded– All engine operating consideration


Acceleration/Climb TradeTypical 767 at Performance Limit

-0.0500

0.0000

0.0500

0.1000

0.1500

0.2000

0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50Acceleration Kt/s

Climb Gradient

175 kts195 kts

175 kts

195 kts

All Engine Takeoff

Engine Inoperative Takeoff

Acceleration/Climb TradeTypical 747 at Performance Limit

-0.0500

0.0000

0.0500

0.1000

0.1500

0.00 0.50 1.00 1.50 2.00 2.50 3.00Acceleration Kt/s

Climb Gradient

175 kts

195 kts

175 kts

195 kts

All Engine Takeoff

Engine Inoperative Takeoff


Geometric Gradient

• Does wind have an affect on the airplane’s climb performance?– Airplane is flying through an air mass– Air mass is moving– Air mass movement relative to the ground does effect

airplane climb performance– Geometric gradient– Drift


Climb Vectors

Consider :

Geometric Gradient = Opposite/adjacent = Tan of the angle

Tan γg = R/CVg

V - true airspeed

Vg - ground speed = V Cos γ - VW

Vγ R/C =

V Cos γVW

dhdt


Workbook Problem

• Do problem 18 in the performance workbook.– Calculate the engine inoperative geometric

gradient for the given conditions.


Turning Flight

• What happens to the airplane’s gradient capability during a turn?– Remember this drawing

Weight = Cos φ ∗ Lift(small angle approximation)

The airplane must increaseα/lift to maintain altitude and create the force causing the turn.

Turning force

What happens to drag if α/lift is increased?

Lift

φ

φ

Weight


Turning Flight

Basic climb equation:

Only change is drag:

( )Vg

dVdh1 +

( )T - Dφ

Wγφ =

Where φ is bank angle required for the turn and Dφ is a function of Lφ = Lzero bank

Cos φ

Gradient = Tan γ = Sin γ = γ =~~ ~

( )Vg

dVdh1 +

( )T - DW


Gradient Decrement in a Turn

• In paper AFM, flight path data is based on zero bank

• Typically it is desirable to determine an increment (reduction) in gradient to adjust the basic wings level(zero) bank data

γφ = γzero bank − Δγφ


Derive Gradient Decrement

γφ = γzero bank − Δγφ

( )Vg

dVdh1 +

γφ =[ ]T − (Dzero bank + ΔDφ)

W

( )T - Dφ

Wγφ =( )V

gdVdh1 +



W = Lzero bank Small climb angle approximation

γφ =( )V

gdVdh1 +

[ ]Dzero bankLzero bank

ΔDφ

WTW

− −

γφ =( )V

gdVdh1 +

[ ]Dzero bankW

ΔDφ

WTW

− −



γφ =( )V

gdVdh1 +

Dzero bankLzero bank

TW

−−

ΔDφ

W

( )Vg

dVdh1 +

γφ = γzero bank −

ΔDφ

W

( )Vg

dVdh1 +


0.8

1

1.2

1.4

1.6

1.8

0.08 0.1 0.12 0.14 0.16 0.18 0.2

CL zero bank

CL zero bankCos φ

CLφ =

ΔCDφ

CD

CL

Gradient Decrement from Drag Polar


Workbook Problem

• Do problem 19 in the performance workbook.– Calculate the gradient decrement in a turn

for the given conditions



Lzero bank = W

γφ =( )V

gdVdh1 +

Dzero bankLzero bank

TW

−−

ΔDφ

W

( )Vg

dVdh1 +


ΔDφ

W

( )Vg

dVdh1 +


ΔDφ

Lzero bank

( )Vg

dVdh1 +

ΔCDφ

CLzero bank

( )Vg

dVdh1 +

= γzero bank −


0.8

1

1.2

1.4

1.6

1.8

0.08 0.1 0.12 0.14 0.16 0.18 0.2

CL zero bank

CL zero bankCos φ

CLφ =

ΔCDφ

CD

CL

Gradient Decrement from Drag Polar


CDφ Function of CLφ = CL zero bank

Cos φ


ΔCDφ = CDφ − CD zero bank

CD zero bank Function of CL zero bank

Δγφ =

ΔCDφ

CL zero bank

( )Vg

dVdh1 +


• Turns out that the CL at V2 is approximately constant across all weights for a given flap

7G7 CL calculation

Flap 20Weight V2 CL

240000 147 1.68220000 141 1.68200000 134 1.69180000 127 1.69160000 119 1.71

Gradient Decrement

0.0000

0.0100

0.0200

0.0300

0.0400

0 5 10 15 20 25 30Bank Angle

Gradient Decrement

Flaps 20 Gradient Decrement basedon CL V2 of 1.7


Effect of Speed and Flap on Climb

How does speed and flap affect the airplane’s ability to climb?

Thrust ?

Aerodynamics ?

Acceleration factor ?

Gradient = Tan γ = Sin γ =~

( )Vg

dVdh1 +

( )TW

DL

−


0.0000

0.0200

0.0400

0.0600

160 165 170 175 180 185 190Velocity Vc

Gradient

747 and 767PW4056 data at representative performance limited weights.



V2

As the Airplane Goes Above the Normal V2,the Climb Gradient Gets Higher


Lift to Drag Comparison

8.00

10.00

12.00

14.00

16.00

18.00

20.00

0.50 0.70 0.90 1.10 1.30 1.50 1.70 1.90 2.10

CLCD

CLAt constant weight, CL goes down as V goes up

Increasing velocity

Flap 2015

5

Up

CL at QRH/FMC V2

CL at flaps up speed

Traditional 7 Series



8.00

10.00

12.00

14.00

16.00

18.00

20.00

0.50 0.70 0.90 1.10 1.30 1.50 1.70 1.90 2.10

CLCD


Increasing velocity

Flap

2015

5

1 CL at V2 chosen for best climb

6.00

25

Traditional MD Series with dial a flap

CL at V2 chosen for best field lengthlowest V2 possible


Effect of Speed and Flap on Climb

• Thrust effect– Increase speed decrease thrust at rated power

• Aerodynamic effect– Flap - higher L/D at less flap (no.), but higher V2

required to meet stall/Vmu/tail clearance– Speed - higher speed, higher L/D until the peak is

reached

• Acceleration factor– Higher speed larger acceleration factor

( )Vg

dVdh1 +

( )TW

DL

−

64


CP, Page 65

FLIGHTOPERATIONS

ENGINEERING


Climb Requirements


Takeoff Flight Path Segment definitions

1stSegment

2ndSegment

3rdSegment

FinalSegment

Liftoff to gear upTarget speed V2Takeoff thrust

Gear up to flap retraction initiationSpeed V2Takeoff thrust

Flap retractionSpeed - accel from V2to flaps up speedTakeoff thrust or MCT

Flaps upFlaps up speedMCT

Gear up

Engine Inoperative


Takeoff Weight Considerations for Climb

• FAR’s define a minimum climb gradient requirement for different parts of the takeoff flight path

• Climb limited takeoff weight is the maximum weight which meets the FAR climb requirements– Point calculation– Flap– Altitude– Temperature– Thrust configuration


Sample Field Length - Gross Weight Plot

FieldLengthRequired


V1mcg Limit

15

5

1Brakeenergylimitation

Tire speed limit - 215 mph


Given: Altitude, temperature

Climb weight limitations


FAR Takeoff Climb Requirements - 25.121

• Climb: One engine inoperative– 25.121 (a) Takeoff; landing gear extended

– Called 1st segment– 25.121 (b) Takeoff; landing gear retracted

– Called 2nd segment– 25.121 (c) Final segment


25.121 (a) Takeoff;Landing Gear Extended 1st Segment

• Begins at liftoff, ends when gear retraction completed

• Critical engine inoperative, worst drag state– Engine inoperative TO thrust– Worst drag configuration, gear doors open– No credit for ground effect

• Weight at initiation of gear retraction

• Gradient Requirement– 2 engine airplane - positive– 3 engine airplane - 0.3 %– 4 engine airplane - 0.5 %


25.121 (b) Takeoff;Landing Gear Retracted 2nd Segment

• Begins at gear up, ends at 400 feet for purposes of climb limited weight calculation

• Conditions– Engine inoperative - Takeoff thrust– Takeoff flap setting, gear retracted– V2 speed

• Calculation typically is done at gear up height

• Gradient Requirement– 2 engine airplane - 2.4 %– 3 engine airplane - 2.7 %– 4 engine airplane - 3.0 %


25.121 (c) Takeoff;Final Takeoff

• Configuration– Engine inoperative MCT thrust– Flaps up

• Calculation is done at 1500 feet - final climb speed

• Gradient Requirement– 2 engine airplane - 1.2 %– 3 engine airplane - 1.5 %– 4 engine airplane - 1.7 %


Climb Weight Calculation

• Calculate weight which meets each of the different climb requirements - the most limiting is the climb limited weight

• W1st

• W2nd

• Wfinal

2nd segment limiting weight is typically the most limiting

}Lowest is the climb limited weight ( )V

gdVdh1 +

( )TW

DL

−


Factors that Affect Climb Weight Limitation

• Takeoff flap– Less flap - better L/D better climb limit weight

– Drawback more field length required

• V2 speed– Choice of V2 will affect 1st/2nd segment climb– QRH/FMC V2 are selected to be as low as possible to

obtain best field length performance

• Thrust– Bleeds, ratings, APR etc.

• Atmospheric Conditions - altitude, temperature– Thrust, acceleration factor, etc.



8.00

10.00

12.00

14.00

16.00

18.00

20.00

0.50 0.70 0.90 1.10 1.30 1.50 1.70 1.90 2.10

CLCD


Increasing velocity

Flap 2015

5

Up

CL at QRH/FMC V2

CL at flaps up speed


Example Climb Weight – Flap Calculation

Field Length - Weight

50006000700080009000

100001100012000

50000 55000 60000 65000 70000 75000 80000

Weight - kg

Fiel

d Le

ngth

- fe

et

Flaps 1 Flaps 5 Flaps 15 Flaps 25

Flaps 25 1

Field Length Limit

Climb Limit

Flaps 1 25

5000 feet, 30 C


Factors that Do Not Affect Climb Weight Limitation

• Wind

• Turn / Bank Angle

• Obstacles

• Remember the climb limitation represents the minimum excess energy at which the airplane is allowed to takeoff, not an actual profile. It is based on gradient relative to the air not the ground.


Methods of Optimizing Climb Limited Weight

• Improved Climb– Schedule an increased V2 above the normal

QRH/FMC V2 speed– Climb gradient will be increased– Excess gradient capability will be traded for

increased weight– Traditional Boeing Method

• Infinite flap selection, dial-a-flap– Allow as many flap positions as possible– Douglas products


Gradient Capability

0.0000

0.0100

0.0200

0.0300

0.0400

0.0500

0.0600

160 165 170 175 180 185 190Velocity Vc

Gradient

767 PW4056 dataEngine Inoperative

V2

160,000 kg

164,000


0.0000

0.0100

0.0200

0.0300

0.0400

0.0500

0.0600

160 165 170 175 180 185 190Velocity Vc

Gradient

767 PW4056 dataEngine Inoperative

V2

160,000 kg

164,0002.4%

Gradient Capability

Could meet legal climb requirements at higher weightby increasing scheduled V2 speed

Could meet legal climb requirements at higher weightby increasing scheduled V2 speed


Improved Climb

• Schedule an increased V2 above the normal QRH/FMC V2 speed

• Climb weight will increase, climb weight will be improved

• What will happen to the the other limit weights if V2 is increased in order to improve the climb limit weight?– Field ?– Tire Speed ?– Obstacle ?– Brake Energy ?


Improved Climb Effect on Field Length/Tire Speed

• Field - Increase in V2 causes increase in field length required– Therefore improved climb can only be done when field

length limited weight is greater than climb limit weight

• Tire Speed - Increase in V2 causes increase in VLO speed– Therefore improved climb results in lower tire speed

limited weight

Standard/QRH/FMC V2Improved climb V2

35 feet


Improved Climb - Obstacle Clearance

Increase in V2 causes increase in field length required and an increase in gradient capability, therefore obstacle clearance capability can either be improved or degraded.

Standard/QRH/FMC V2

Improved climb V2

35 feetClose in obstacle clearance capability degraded

Distant obstacleclearance capabilityimproved


Improved Climb

Improved climb causes an increase in V1, which increases the possibility of being limited by Vmbe.

Distance

Choice of V1

1.15 AE distance

EI A-G distance

Given weight, altitude, temp

A-S distance

1.15 AE

Improved climbhigher VR, V2

VR ICVR QRH/FMC


Improved Climb Data

Field Length - Weight

50006000700080009000

100001100012000

50000 55000 60000 65000 70000 75000 80000

Weight - kg

Fiel

d Le

ngth

- fe

et

Flaps 1 Flaps 5 Flaps 15 Flaps 25

Flaps 25 1

Field Length Limit

Climb Limit @ max IC

Flaps 1 25

5000 feet, 30 C, optimum IC


15 with IC

5 with IC

1 with IC

FieldLengthRequired


V1mcg Limit

15

5

1


Given: Altitude, temperature

No improved climbImproved climb

Climb weight limitations


Height to Gear Up Determination

• Gear up height is measured during the airplane flight test programs

• Gear up height is a function of the airplanes ability to climb and accelerate

• Factors effecting gear up height– Acceleration (how the airplane is flown)– Atmospheric condition (altitude/temperature)– Configuration / Thrust (flap, bleed etc.)

Δh35’-GUΔs35’-GU

=1 ΔV35’-GUg Δt35’-GU

+ ( )TW

DL−


Another FAR Takeoff Climb Requirement -25.111 (3)

• At each point along the takeoff path, starting at the point at which the airplane reaches 400 feet above the takeoff surface,the available gradient of climb may not be less than

(i) 1.2 percent for two-engine airplanes

(ii) 1.5 percent for three-engine airplanes

(iii) 1.7 percent for four-engine airplanes

• This requirement effects extended second segment obstacle clearance - limits the maximum allowable weight to use extended second segment method


Obstacle Requirements and Considerations


§ 121.189 Airplanes: Turbine Engine Powered: Takeoff Limitations - Excerpts

(d).….(2) In the case of an airplane certificated after September 30, 1958 (SR 422A, 422B), that allows a net takeoff flight path that clears all obstacles either by a height of at least 35 feet vertically, or by at least 200 feet horizontally within the airport boundaries and by at least 300 feet horizontally after passing the (airport) boundaries…….

….(f) For the purposes of this section, it is assumed that the airplane is not banked before reaching a height of 50 feet, as shown by the takeoff path or net takeoff flight path data (as appropriate) in the Airplane Flight Manual, and thereafter that the maximum bank is not more than 15 degrees.


AC 120-91 (approved 5/5/06)

• Area analysis method – Defines an obstacle accountability area (OAA) within

which all obstacles must be cleared vertically– OAA is centered on the intended flight track

– Do not need to account for– Wind, available guidance, pilotage in turns

• Flight track analysis method – Alternative means of defining an OAA based on the

navigational capabilities of the aircraft. – Operator required to evaluate the effect of:

– Wind and available course guidance on the actual ground track, pilotage in turns.




§ 25.115 Takeoff Flight Path

(a) The takeoff flight path shall be considered to begin 35 feet above the takeoff surface at the end of the takeoff distance determined in accordance with § 25.113(a) or (b), as appropriate for the runway surface condition.

(b) The net takeoff flight path data must be determined so that they represent the actual takeoff flight paths reduced at each point by a gradient of climb equal to(1) 0.8 percent for two-engine airplanes;(2) 0.9 percent for three-engine airplanes; and(3) 1.0 percent for four-engine airplanes.


§ 25.115 Takeoff Flight Path

(c) The prescribed reduction in climb gradient may be applied as an equivalent reduction in acceleration along that part of the takeoff flight path at which the airplane is accelerated in level flight.

continued


“Legal” Takeoff Flight Path

Gross Flight Path - Best prediction of the airplanes actual performance

Net Flight Path - Gross performance reduced by a gradient conservatism

γnet = γgross − ΔγFAR defined g conservatism

ΔγFAR defined g conservatism{ 0.008 - 2 eng airplane0.009 - 3 eng airplane0.010 - 4 eng airplane

Engine Inoperative

2nd SegmentConstant V2 climb

3rd SegmentFlap retraction

Final SegmentFlaps up climb

Gear up

35 feet - Reference Zero


§ JAR-OPS 1.495 (a) - Take-off Obstacle Clearance

An operator shall ensure that the net take-off flight path clears all obstacles by a vertical distance of at least 35 ft or by a horizontal distance of at least 90 m plus 0.125 x D, where D is the horizontal distance the aeroplane has traveled from the end of the take-off distance available or the end of the take-off distance if a turn is scheduled before the end of the take-off distance

[available. For aeroplanes with a wingspan of less than 60 m a horizontal obstacle clearance of half the aeroplane wingspan plus 60 m, plus 0.125 x D may be used.(See IEM OPS 1.495(a).)]


§ JAR-OPS 1.495 - Take-off Obstacle Clearance (a)

180 m+

12.5 %

Band*width

* Dependent on flight path and navigational capability+ For airplanes with wingspan less than 60 m, then start band

width is 120 m


§ JAR-OPS 1.495 (b) - Take-off Obstacle Clearance

• When showing compliance with subparagraph (a) above, an operator must take account of the following:(1) The mass of the aeroplane at the

commencement of the take-off run;(2) The pressure altitude at the aerodrome;(3) The ambient temperature at the aerodrome;

and(4) Not more than 50% of the reported head-

wind component or not less than 150% of the reported tailwind component.


§ JAR-OPS 1.495 (c) - Take-off Obstacle Clearance

• When showing compliance with subparagraph (a) above:(1) Track changes shall not be allowed up to the

point at which the net take-off flight path has achieved a height equal to one half the wingspan but not less than 50 feet above the elevation of the end of the take-off run available. Thereafter, up to a height of 400 ft it is assumed that the aeroplane is banked by no more than 15°. Above 400 feet height bank angles greater than 15°, but not more than 25°may be scheduled;



(2) Any part of the net take-off flight path in which the aeroplane is banked by more than than 15°must clear all obstacles within the horizontal distances specified in sub-paragraphs (a), (d) and (e) of this paragraph by a vertical distance of at least 50 feet; and

[(3) An operator must use special procedures, subject to the approval of the Authority, to apply increased bank angles of not more than 20°between 200 feet and 400 feet, or not more than 30° above 400 feet (See Appendix 1 to JAR-OPS 1.495(c)(3)).]



([(4)] Adequate allowance must be made for the effect of bank angle on operating speeds and flight path including the distance increments resulting from increased operating speeds. (See AMC OPS 1.495(c)(4)).


§ JAR-OPS 1.495 (d) - Take-off Obstacle Clearance

• When showing compliance with subparagraph (a) above for those cases where the intended flight path does not require track changes of more than 15°, an operator need not consider those obstacles which have a lateral distance greater than:(1) 300 m, if the pilot is able to maintain the

required navigational accuracy through the [obstacle accountability area (See AMC OPS 1.495(d)(1) and (e)(1); or]

(2) 600 m, for flights under all other conditions.


§ JAR-OPS 1.495 - Take-off Obstacle Clearance (d)

* Less than 15 degree track change

Required navigational accuracy - 300 m half width600 m band width

All other conditions - 600 m half width1200 m band width

+ For airplanes with wingspan less than 60 m, then start band width is 120 m

180 m+

12.5 %

Band*width


§ JAR-OPS 1.495 (e) - Take-off Obstacle Clearance

• When showing compliance with subparagraph (a) above for those cases where the intended flight path does require track changes of more than 15°, an operator need not consider those obstacles which have a lateral distance greater than:

(1) 600 m, if the pilot is able to maintain the required navigational accuracy through the [obstacle accountability area (See AMC OPS 1.495 (d)(1) and (e)(1)); or]

(2) 900 m for flights under all other conditions.


§ JAR-OPS 1.495 - Take-off Obstacle Clearance (e)

* Greater than 15 degree track change

Required navigational accuracy - 600 m half width1200 m band width

All other conditions - 900 m half width1800 m band width

+ For airplanes with wingspan less than 60 m, then start band width is 120 m

180 m+

Band*Width


Obstacle Analysis

• Flight Paths used for obstacle analysis– Second Segment– Extended Second Segment– Final Segment

• Other options/considerations– Straight out departure– Turning flight– Level off height


Second Segment Flight Path

GrossNet

End of flap retractionor TO thrust time limit

Level off height

Flap retraction segment

Constant V2 climbtakeoff flap

Profile Assumes Engine Failure at Critical Point

Brakerelease

Basic second segment flight pathassumes climb at V2/takeoff flap until gross level off height is reached. Retract flaps at TO thrust


Second Segment Flight PathProfile Assumes Engine Failure at Critical Point

35 feetreference zero

Brakerelease

GrossNet

End of flap retractionor TO thrust time limit

Level off height



Level off height - gross height where engine inoperative flap retraction is initiated.

Minimum allowed per FAR 25.111 is 400 feet

Maximum for second segment flight path is the height which results in the flap retraction being completed at the TO thrust time limit - 5/10 minutes


Extended Second Segment Flight Path

BrakeRelease

GrossNet

Flap retractionaccomplished at MCT

Level off height



35 feetReference Zero


Extended second segment flight pathassumes Climb at V2/takeoff flap until gross level off height is reached. Flap retraction is accomplished at MCT


Additional Extended Second Segment Consideration

• Flap retraction performed at MCT not TO– In order to meet 25.111 (3)

– At each point along the takeoff path, starting at the point at which the airplane reaches 400 feet above the takeoff surface,the available gradient of climb may not be less than(i) 1.2 percent for two-engine airplanes

(ii) 1.5 percent for three-engine airplanes

(iii) 1.7 percent for four-engine airplanes– Must calculate weight which can meet gradient

requirement at takeoff flap and MCT power– This weight is checked against obstacle limited weight.

Most restrictive is used.


Final Segment Flight Path

BrakeRelease

Gross

Net

Level off height


Constant V2 climbTakeoff flap

Flaps upMCT

35 feetReference Zero


Level off height - gross height where engine inoperative flap retraction is initiated.

Minimum allowed per FAR 25.111 is 400 feet


Flight Path Choice

• Second Segment Flight Path– Best for close in obstacles, typically less than

40,000 feet from reference zero

• Extended Second Segment Flight Path– Best for medium distance obstacles, typically

between 40,000 feet and 75,000 from reference zero

• Final Segment Flight Path – Best for distant obstacles, typically greater

than 75,000 feet from reference zero


Turning Flight

• Often obstacle limited weight can be increased by planning a turn to avoid the obstacle.

• Turn considerations include the following– Point of turn initiation, end of turn

– Nav aid, altitude, landmark etc.– How turn is flown

– Constant bank, constant radius, other?

– Airplane performance change during a turn– Gradient loss, effect of wind


Physics of Turning Flight

• What force causes an airplane to turn?– Remember this drawing

Turning Force = Sin φ ∗ Lift

Turning force created by lift force in the direction of turn.

Remember: L∗Cos φ = W

LW = 1

Cos φ

Turning force Lift

φ

φ

Weight



Velocity at =

Rdθdt

dVdt

V Σ FN L*Sin φ = M aN

Also : V = R dθdt

dθdt

VR

=

W = L Cos φ

Substitute W and dθ/dt into turning force equation

an =

L*Sin φ = Wg

V dθdt

dθdt

Coordinated Turn (zero sideslip)



Re-arranging

VL*Sin φR = VL Cos φ

g

V2

g Tan φ R = Radius of turn is only a functionof TAS and bank angle

VRL*Sin φ = VL Cos φ

g

L*Sin φ = dφdt

VWg



Turn Radius

0 10 20 30Bank Angle - Degrees

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

10000

Turn Radius -Feet

TAS120

170160150140130

110



Turn Radius

• What is the turn radius of a 737 at a 15 degree bank flying 150 TAS ?

7510 feet

• What is the turn radius of a 747 at the same speed and bank angle ?

7510 feet



Coordinated Uncoordinated

β ≠ 0

β = 0

β ≠ 0

“skid”

“slip”


Turn Radius

• What about turn performance with an engine failed?

• Can we assume this is also a coordinated turn, with zero sideslip?

Engine Inoperative


Engine Inoperative Trim Technique

•It is not possible to trim for zero sideslip on takeoff, missed approach, or go-around, at high thrust settings, with one engine failed

•Pilots are trained to trim for zero wheel, to achieve near minimum drag, for best gradient


β ≠ 0 β ≠ 0

Turns into the failed engine

Turns away fromthe failed engine

Example: right engine has failed, airplane turning left:

Example: left engine has failed, airplane turning left:

V2Actual R exceeds g*tan(Φ)

V2Actual R is less than g*tan(Φ)


Turn Radius Summary

• V2/g*tan(Φ) may not accurately model turn radius with an engine failed:– With constant bank angle:

– Turns toward the failed engine will turn inside the classical radius

– Turns away from the failed engine will exceed the classical radius

– For constant radius turns:– Turns toward the failed engine will require less bank– Turns away from the failed engine will require more

bank

Engine Inoperative


Turn Radius SummaryEngine Inoperative

• The engine inoperative turn radius effect just described has not traditionally been included in turn radius calculations for Seattle models

• Some Douglas models have included it

• Boeing intends to update AFM-DPI, BTM and the Boeing Climbout Program (BCOP) software to improve the accuracy of engine out lateral track calculations, for all in-production models.


Sample Obstacle Analysis



• Determine obstacles/Terrain to be considered– Obtain obstacle data

– Type A chart - ICAO database– Airline survey of airport - Terrain maps– Commercial source


– Lay out flight path to be analyzed– Straight out/turning flight– Eliminate obstacles outside of area to be

considered– If turning, determine appropriate turn

procedure – If turning and using straight out obstacle

analysis method or program, adjust obstacle height to account for turn


Determine Proposed Flight Path and Obstacles

Innsbruck (LOWI) Rwy 26 departure and engine failure escape path


Innsbruck (LOWI) Runway 26 departure



Terrain Being Considered

1500

2000

2500

3000

3500

4000

4500

5000

0 10 20 30 40Distance - NM

Height - Feet



• Determine most limiting weight not considering obstacles

• Analyze this weight and determine if this weight will clear all the obstructions.– Obstacle not cleared, try lower weight and

iterate until obstacle is cleared– Obstacle is cleared, determine minimum

level off height for flap retraction, publish weight and height

continued


Sample Obstacles

1500

2000

2500

3000

3500

4000

4500

5000

0 10 20 30 40Distance - NM

Height - Feet

GrossNet


Items that Affect Obstacle Clearance

• Choice of flap– More deflected flap may be better for close in

obstacle– Less deflected flap has a better climb gradient

and will be better for more distant obstacle

• Thrust - more thrust is good

• Improved Climb - same idea as flap

• Wind - Headwind is good, tailwind is bad


Items that Affect Obstacle Clearance

• Turning affects gradient which affects climb profile– If analysis is being done with a turn, the climb

gradient is degraded during turn segment (AFM-DPI/BTM analysis)

– An equivalent analysis can be done as a straight out departure with the obstacle height increased by an amount equal to the gradient loss during the turn (Mark7J/BTOPS/Paper AFM type analysis)


16. On a two engine airplane, the climb capability will always equal or exceed 2.4 % gradient relative to the air in the second segment region of the takeoff. (True/False)

False, the airplanes climb capability in the 2nd segment is a maximum at the gear up point. Before gear is retracted the extra drag reduces the climb capability. Above the gear retraction point the reduced air density reduces the airplanes climb capability as the airplane climbs to higher pressure altitudes due to thrust reduction at rated power.


17. At a performance limited takeoff weight a four engine airplane has better climb capability than a two engine airplane when all engines are operating. (True/False)

18. A performance limited 4 engine airplane will be able to safely continue the takeoff and climb out following a dual engine failure on the runway at the rotation speed. (True/False)

False, at the performance limited takeoff weight the two engine airplane typically has a 30 to 60 % greater climb capability with all engines operating normally. (measured by gradient)

False, when at the performance limited condition the 4 engine airplane cannot climb with a two engine failure.


19. Headwind will always improve my legal performance limited takeoff weight. (True/False)

20. More takeoff thrust will always improve my legal performance limited takeoff weight. (True/False)

False on a technicality, wind does not effect the climb weight limitation therefore if the airplane is climb limited, headwind does not effect the legal performance limited takeoff weight. Headwind will improve the field, obstacle, tire speed and brake energy takeoff weight limitations.

False, when limited by minimum control speed, less thrust (derate) will improve the field length limited takeoff weight. The brake energy limited takeoff weight will also be slightly reduced with more takeoff thrust.


21. The maximum brake energy speed is based on brakes at the wear limit. (True/False)

22. All airlines use the same definition of obstacles. (True/False)

True, this safe guard has been accomplished either during initial certification or retroactively by Airworthiness Directive.

False, there isn’t an “official” source of obstacle data or engine out procedures. Airlines are free to determine the optimum flight path for their operation and therefore may consider different obstacles.


23. The maximum level off height is the height attained at the takeoff thrust time limit, either 5 or 10 minutes, after takeoffassuming an engine failure at VEF, a constant speed climb at takeoff flap and takeoff thrust. (True/False)

24. The 787 is being designed to the same FAR performance requirements as the 747-100. (True/False)

This is true and false; for a “extended 2nd segment“ analysis this is true. For a traditional “2nd segment” analysis the maximum level off height is the maximum height the airplane can achieve and then complete flap retraction in level flight within the takeoff thrust time limit.

False, the FAR’s are a continuously evolving set of requirements.

CL, Page 1

FLIGHTOPERATIONS

ENGINEERING


Enroute Climb

CL, Page 2For Training Purposes Only Copyright © 2009 Boeing. All rights reserved

Enroute Climb Modes

• “Strategic” Modes– Min Fuel Minimize climb fuel CI = 0– Min Time Minimize trip time CI = max– Min Cost Minimize climb cost CI = K

• “Tactical” Modes– Max Angle Maximize dh/dx Vx– Max Rate Maximize dh/dt Vy– Required Time Time at waypoint

of Arrival (RTA)

Mode Constraint Speed


Climb Speed Selection

A constant KCAS/Mach climb schedule is typically chosen for practical reasons (pilots and ATC). These speeds are chosen to approximate the precise theoretical speed for any given mode.


Climb Speed Selection

Constant Mach numbers

Tropopause

True Airspeed, V

Best R/C speed

True Altitude

Initial cruise mach number and altitude

Constant VC


Crossover Altitude and Speed Envelope

Crossover altitude

True Airspeed, V

True AltitudeClimb speed schedule

MM

O

V MO


Additional ConsiderationsSpeed Constraints

FAR 91.117

Aircraft speed.

(a) Unless otherwise authorized by the Administrator, no person may operate an aircraft below 10,000 feet MSL at an indicated airspeed of more than 250 knots (288 m.p.h.).

•••

(d) If the minimum safe airspeed for any particular operation is greater than the maximum speed prescribed in this section, the aircraft may be operated at that minimum speed. (e.g. Heavy-weight 747-400)


Flight Management System (FMS)Control Display Unit (CDU) Climb Page


Max Angle Climb

Used for:– obstacle clearance– climbing above traffic

dhdx

Chosen to maximize

Also known as Vx

Vx will decrease slightly as weight is burned off

Vx


Max Angle Climb

(T − D)WSin γ =

True Airspeed, V

Thrust, Drag

Thrust

Drag

Vx


Max Rate Climb

*Note: To fly Max Rate below 10,000 ft, the 250KIAS/10,000 ft speed restriction must be deleted

Used for:– Minimum time to climb– Sometimes requested

by ATC

Constant VC which approximates Vy

Chosen to maximize

ΔhΔt

dhdt≈


Max Rate Climb

True Airspeed, V

Thrust, Drag

Thrust

Drag

Vx Vy

R/C = V sin γ = V (T – D)W


ECON Climb

ECON Climb Speed = f(Cost Index, CI)

$/hrCents/lb

Time CostFuel Cost

CI = =

Low CI low speed, low fuel burn, high trip timeLow CI low speed

High CI high speed, high trip fuel, low trip timeHigh CI high speed


ECON Climb

Minimum cost is determined by summing time and fuel costs at the specified Cost Index, and then finding the minimum...

Speed

Cost

Time CostFu

el Cos

t

Total Cost =Fuel Cost + Time Cost*

Minimum fuel ECON


ECON Climb

Cost must be evaluated between two common points:

Distance

Altitude

A

BInitial cruise

altitude

Cost indexIncreasing

Min

fuel

Min time


Climb Time Trades

20.0

25.0

30.0

35.0

40.0

200 220 240 260 280 300 320 340Climb Speed - knots until M0.8 Crossover

Tim

e - m

inut

es

Time to 200 nm time to altitude

Climb from Sea Level to 35000 feet

VMO


Climb DistanceTrades

120

130

140

150

160


Dis

tanc

e - n

m

Climb from Sea Level to 35000 feetVMO


Climb Fuel Trades

2200

2300

2400

2500

2600

2700

2800


Fuel

Bur

ned

- kg

Climb from Sea Level to 35000 feet, cruise to common end point of 200 nm

VMO


Workbook Problem

• Do problem 19 in the performance workbook– Questions on CL.15 - 17


ECON Climb

Cost Index is entered on the Performance Initialization(PERF INIT) page:

Cost Index = 0 Minimum Fuel

Cost Index = Max Minimum Trip Time*

*Note: Not minimum climb time


Required Time of Arrival (RTA)

FMC internally iterates on Cost Index to meet specifiedarrival time constraint at agiven waypoint...


Method of Calculating Climb Time, Fuel, and Distance

1. Determine altitude integration step h1 to h2

12. For multiple altitude steps, sum the total of ΔFuel

11. Determine delta fuel for the step

10. Determine the fuel flow at average altitude, Wfavg

9. For multiple altitude steps, sum the total of delta distances

8. Calculate incremental distance for the step

7. Calculate average true airspeed over the step Vavg

6. For multiple steps, sum the total of delta times

5. Calculate delta time for the step

4. Calculate average rate of climb at the altitude havg

3. Calculate Δh for the step

2. Calculate average altitude for step havg = ( h2 + h1)/2

Δh = h2 − h1

ΔhR/Cavg

Δt =

VavgΔt60ΔNAM =

Δt x Wfavg60ΔFuel =


Integrating to Calculate Climb Performance

H1p to H2p

(1)Select

havg

(2)Average

Δhp

(3)H2p - H1p

Δhtrue

(4)

Wavg

(5)Assume

R/Cavg

(6)Calculate

Δt

(7)(4) ÷ (6)

Sum ofΔt

(8)

Vavg

(9)Calculate

Add upΔNAM(11)

Wfavg(12)From

EngineData

(14)

Sum ofΔFuelΔNAM

(10)(9) x (7)

60

ΔFuel(13)

(12) x (7)60


• PRESSURE GRND AIR IAS EAS GRND FUEL CL D FN N1-1 ACC GRAD POW

• ALTITUDE WEIGHT FUEL DIST DIST TIME CAS TAS MACH SPD FLOW CD D/DELTA FN/DELTA N1-2 FACT BODY R/C SET

• FT KG KG NM NM H:M KTS KTS KTS KG/HR LBS LBS ANGLE FPM

• ------------------------------------------------------------------------------------------------------------------------------------

• * 2000 74705 295 1. 1 0:02.3

• 2500 74686 39 1.5 1.5 :00.3 280.0 279.4 .4421 288.2 7490 0.4617 9209 29131 92.0 0.1045 .1102 3216.5 1

• 280.0 289.9 .02598 10087 31911 9.35

• * 3000 74667 333 2. 2 0:02.6

• 3500 74647 39 1.5 1.5 :00.3 280.0 279.2 .4500 292.4 7360 0.4624 9209 28533 92.3 0.1080 .1066 3155.7 1

• 280.0 294.0 .02602 10467 32430 9.15

• * 4000 74628 372 4. 4 0:02.9

• 4500 74608 39 1.6 1.6 :00.3 280.0 278.9 .4580 296.7 7227 0.4632 9209 27928 92.6 0.1117 .1029 3091.9 1

• 280.0 298.2 .02607 10862 32944 8.94

• * 5000 74589 411 5. 5 0:03.3

• 5500 74569 39 1.7 1.7 :00.3 280.0 278.7 .4662 301.0 7096 0.4640 9208 27339 92.8 0.1154 .0994 3029.0 1

• 280.0 302.5 .02611 11276 33479 8.74

• * 6000 74550 450 7. 7 0:03.6

• 6500 74530 39 1.7 1.7 :00.3 280.0 278.4 .4746 305.5 6968 0.4648 9207 26767 93.1 0.1194 .0959 2966.9 1

• 280.0 306.9 .02616 11708 34038 8.55

• * 7000 74511 489 9. 9 0:03.9

• 7500 74491 39 1.8 1.8 :00.3 280.0 278.1 .4832 310.0 6838 0.4656 9206 26190 93.4 0.1234 .0924 2902.0 1

• 280.0 311.3 .02621 12160 34593 8.35

• * 8000 74471 529 11. 11 0:04.3

• 8500 74452 39 1.8 1.8 :00.4 280.0 277.8 .4920 314.6 6707 0.4665 9206 25610 93.6 0.1277 .0890 2834.4 1

• 280.0 315.8 .02627 12634 35145 8.15

• * 9000 74432 568 12. 12 0:04.6

• 9500 74412 40 1.9 1.9 :00.4 280.0 277.5 .5010 319.3 6577 0.4674 9206 25030 93.8 0.1320 .0855 2764.7 1

• 280.0 320.4 .02633 13130 35698 7.95

• * 10000 74392 608 14. 14 0:05.0

• 10500 74372 40 2.0 2.0 :00.4 280.0 277.2 .5103 324.0 6455 0.4684 9206 24471 94.1 0.1366 .0822 2696.9 1

• 280.0 325.1 .02639 13649 36281 7.76

• * 11000 74352 648 16. 16 0:05.4

• 11500 74332 40 2.1 2.1 :00.4 280.0 276.9 .5197 328.9 6336 0.4694 9205 23910 94.4 0.1413 .0789 2626.9 1

280.0 329.9 .02645 14192 36864 7.57

Excerpt from Boeing Inflight Program


Distance - NAM

Pressure Altitude

Fuel - kgTime - Hours

Initia

l clim

b we

ight

Incr

easin

g

Initia

l clim

b we

ight

Incr

easin

g

Initi

al c

limb

wei

ght

Incr

easin

g

• Climb Thrust• Given Temp

Weight Effect on Climb


Climb Presentation (FPPM)


Enroute Climb Summary

• Looked at climb speed selection and physics of common “tactical” and “strategic” objectives

• Primary method of calculation is by step integration

CL, Page 27

FLIGHTOPERATIONS

ENGINEERING


Enroute Cruise


Los AngelesLos Angeles

Mexico CityMexico City

Rio de JaneiroRio de Janeiro

Cape TownCape Town

ManilaManila

BeijingBeijing

SeoulSeoul

TokyoTokyo

LondonLondon

Buenos AiresBuenos Aires

LimaLima

Range Capability from LondonFull Passenger Payload

767-300ER406,795-lb (184,520-kg) TOGW*218 three-class passengers

767-400ER439,765-lb (199,480-kg) TOGW*245 three-class passengers

• Typical mission rules• Airways and traffic

allowance included• 85% annual winds

* Fuel volume limited


Fuel capacity

U.S. gal (L)

24,140 (91,370)

Payload-Range CapabilityGeneral Electric Engines

Maximum Zero Fuel Weight Maximum

Takeoff Weight

Maximum Fuel

Capacity

(0)

(10)

(20)

(30)

(40)

(50)

(0)

(20)

(40)

(60)

(80)

(100)

(120)

0 1 2 3 4 5 6 7 8 9

(0) (2) (4) (6) (8) (10) (12) (14) (16)

Range, 1,000 nmi (1,000 km)

Payload, 1,000 lb (1,000 kg)

• Three-class seating• Typical mission rules

218 passengers

767-300ER380,000-lb (172,365-kg) MTOW

767-300ER412,000-lb (186,880-kg) MTOW


Payload-Range Comparisons

0

50

100

150

200

250

0 5 10 15 20 25 30Still Air Range (1000 nm)

Payload (1000 lb)

Lockheed C5 Galaxy

Boeing 777 (635K)

Rutan Voyager


Mission ProfileTypical Mission Rules

• Standard day• Fuel density 6.7 lb/U.S. gal• Nominal performance• Passengers at 210 lb (95 kg) (passenger + baggage)

Mission Reserves

Still air rangeFlight time and fuelBlock time and fuel

Taxi

out (

9 min)

Take

off to

35 ft

Clim

b to 1

,500 f

t and

acce

lerate

to 25

0 kias

Clim

b to 1

0,000

ft at

250 k

ias

Acce

lerate

to cl

imb s

peed

Clim

bCruise

Desc

end t

o 1,50

0 ft

Appr

oach

and l

and (

5 min)

Taxi

in (5

min

from

rese

rves)

200 nmi

LRC5% fli

ght fu

el

Miss

ed ap

proa

ch

Econ

omy c

limb

Econ

omy d

esce

nt

Appr

oach

and l

and (

5 min)

30-m

in ho

ld at

1,500

ft


NAMkgFUEL

ΔRΔWTFUELBURNED

=

So, if we want to maximize range for constant amount of fuel to be burned, we need to maximize Fuel Mileage

Primary Parameters for Range

OR

For a given range, to minimize the quantity of fuel burned, it is necessary to maximize the fuel mileage.

ΔR = ∗ ΔWTFUELBURNEDNAM

kgFUEL


Fuel Mileage - 37,000 Feet

Fuel Mileage -NAM/lbF

Mach

0.06

0.13

0.07

0.08

0.09

0.10

0.11

0.12

.56 .60 .64 .68 .72 .76 .80 .84

Weight (1000 lb)

Long range cruise

MMO

MCRT limit

80

85

9095

100105

110 115120

125130

135140

145150

155160


Substituting Earlier Definitions

(Nm/hr)(Kg/hr)

VWF

NAMkg ==

In level flight: T = D, L = W

NAMkgFUEL

∗ Δ WTFUELBURNEDΔR =

WF = TSFC*T

V = Ma0 θ

Inserting these relationships into our range equation:

ΔR =a0 θTSFC

ΔWW

MLD

Integrating with respect to weight:

R =a0 θTSFC

W1W2

MLD ln ( )


Take a step back

Rearranging the equation from the previous page:

What happens to the fuel mileage if the drag is increased by 1% ?

What happens to the fuel mileage if the TSFC is increased by 1% ?

What happens to the fuel mileage if the weight is increased by 1% ? Be careful, think about it before answering !!!!

(Nm/hr)(Kg/hr)

VWF

NAMkg ==

FuelMileage = ΔR

ΔWa0 θTSFC

1W

MLD==


Lift/Drag Ratio and Aerodynamic Efficiency

L/D

10

11

12

13

14

15

16

17

18

19

0.55 0.6 0.65 0.7 0.75 0.8 0.85 0.9

L/D

ML/D

MACH

757-200, W/δ = 850,000 lb

ML/D


Thrust - TSFC Performance

0.156

0.157

0.158

0.159

0.160

0.161

0.162

0.163

0.164

20000 24000 28000 32000 36000

TSFCTSFC - lb/hr per lbFn

FN/δ (per engine)

35,000 ft, MACH = 0.80


Thrust Required for Level Flight

35,000 ft, MACH = 0.80

20000

22000

24000

26000

28000

30000

32000

0.6 0.7 0.8 0.9 1 1.1

Thrust Required -lb/engine

W/δ x 10 -6

160,000 lb

200,000 lb

240,000 lb


Speed Stability

45000

50000

55000

60000

65000

70000

75000

0.55 0.6 0.65 0.7 0.75 0.8 0.85 0.9

Drag/δ

FN/δDrag/δ, FN/δ

MACH

W/δ = 850,000 lb, Standard Day

Maximum CruiseThrust

Approximateconstant thrustlever position

Speed unstable Speed stable


Altitude Effect on Fuel Mileage

0.05

0.052

0.054

0.056

0.058

0.06

0.062

0.064

0.066

0.068

31000 33000 35000 37000 39000 41000

MACH = 0.80

Fuel Mileage -NAM/lb

Altitude (ft)

230,000 lb

200,000 lb

170,000 lb

W/δ = 9.2 x 106


0.04

0.045

0.05

0.055

0.06

0.065

0.07

0.075

150000 170000 190000 210000 230000 250000

Fuel Mileage Summary

MACH = 0.80, standard day, all-engine, 2 packs normal flow

Fuel Mileage -NAM/lb

Weight - lb

25272931

33

3537

3941

Altitude - 1000 ft

Optimum Altitude


Optimum and Maximum Altitude

32

34

36

38

40

42

140 150 160 170 180 190 200 210 220 230 240Gross Weight – 1000 lb

Altitude -1000 ft

CI = 100, all-engine, 2 packs normal flow

Buffet-limitedMaximumAltitude

Thrust-limitedMaximumAltitude

ISA to ISA + 10C

Max Cert Alt

ISA + 15COptimum Altitude


Maximum Altitude

Defined by Thrust / Drag relationship• User-defined limit thrust, and• Residual Rate of Climb (RROC)

• Typical • MCLT – 300 or 500 FPM

• MCRT – 0 or 100 FPM• Temperature-dependent!

Buffet-Limited Maximum AltitudeDefined by Initial Buffet CL• User-defined maneuver margin• Optional cruise CG

Thrust-Limited Maximum Altitude


CL Versus Mach

In cruise, CL is given by:

where “n” is load factor, in “g”...

CL = nW1481.351 ∗ M2SREFδ

CL = K nWδ

1M2


Initial Buffet Boundary

0.5

0.6

0.7

0.8

0.9

1

1.1

1.2

.60 .62 .64 .66 .68 .70 .72 .74 .76 .78 .80 .82 .84Mach Number

Lift Coefficient

Initial BuffetCL

1.2 x 10 6lb

1.4 x 10 6lb1.0 x 10 6lbnWδ


Maneuver Margin Effect on Buffet

0.5

0.6

0.7

0.8

0.9

1

1.1

1.2

.60 .62 .64 .66 .68 .70 .72 .74 .76 .78 .80 .82 .84Mach Number

Lift Coefficient

1.3g

1.5g

1.1g“n”

• Weight = 100,000 kg• Altitude = 35,000 ft


Altitude Effect on Buffet Envelope

0.5

0.6

0.7

0.8

0.9

1

1.1

1.2

.60 .62 .64 .66 .68 .70 .72 .74 .76 .78 .80 .82 .84Mach Number

Lift Coefficient

35,000 ft

38,000 ft31,000 ftAltitude

• Weight = 100,000 kg• n = 1.3g


Flight Management System (FMS)Control Display Unit (CDU)

For example only

Depending on airplane limits may be displayed on Airline Policy or Perf Factors page as appropriate


Effect of WindEquivalent Still Air Distance

ESAD = ∗ DistGRNDV

V + VW

DistAir =V ∗ DistGRND

VG

Time = =DistGRND

VG

DistAirV


Operations Manual Air Distance Table

*NOTE: This table is applicable only for the specified cruise speed schedule


Effect of Temperature

• Increased fuel mileage less fuel required

For a given range, ΔR:

• Decreased fuel mileage more fuel required

Δ WTFUELBURNED =ΔR

NAMkgFUEL


Effect of Temperature

How does temperature effect:TSFC ?Drag ?Mach ? ? True AirspeedLift/Weight ?

(Nm/hr)(Kg/hr)

VWF

NAMkg ==

FuelMileage = ΔR

ΔWa0 θTSFC

1W

MLD==

a0 θ


Temperature Effect on True Airspeed

For our example case, ISA + 20C at 35,000 ft, constant Mach:

θISA = 0.7595, θISA+20C=.8289

V = Ma0 θ

=Vnon-std

Vstd

θnon-stdθstd

.5

=Vnon-std

Vstd

.8289

.7595

.5

= 1.0447


Temperature Effect on Fuel FlowTemperature effect on fuel flow

1.054

35,000


Temperature Effect on Drag

We have already calculated the temperature effect on WF for a constant thrust required (drag) condition.

Does temperature have any effect on drag /thrust required which will require another adjustment to be applied to WF?

CDNOM = ƒ(Mach, W/ δ ), so if W/ δ is constant, and we are flying a constant Mach, CDNOM will not change, but

What about Reynolds number correction?


RERE

Assuming M 0.8, 35,000 feet, ISA + 20 C and 130,000 lb

ΔCD RE ALT = - 0.000065ΔCD RE Temp = + 0.000330ΔCD RE = + 0.000265


Nominal CD for 130,000 lb, M 0.8, 35000 ft = 0.2748

Delta CD RE for conditions = 0.000265

Total CD = .02775

Drag Factor due to ISA + 20 C for this condition = 1.01

Temperature Effect on ΔCD RERE


Effect of Temperature on Fuel Mileage

NAMKg FUEL ISA + 20C

=VISA + 20C

WF=

1.045 ∗ Vstd day

1.01*1.054 ∗ WF Std day

NAMkgFUEL ISA + 20C

= 0.981 ∗ NAMkgFUEL std

What is the total effect on fuel mileage of ISA+20 C and theseConditions (130,000 lb, M 0.8, 35,000 ft.


Flight Management System (FMS)Control Display Unit (CDU)

ECON Cruise Page


ECON Cruise

ECON Cruise Mach = f(Cost Index, CI)

High CI high speed, high trip fuel, low trip time

Low CI low speed, low fuel burn, high trip time

TimeCostFuelCostCI = = $/hr

cents/lb


ECON Cruise

Minimum cost is determined by summing time and fuel costs at the specified Cost Index, and then finding the minimum...

* Fixed Costs are neglected since they do

not affect CI

Speed

Cost

Time Cost

Fuel

Cost

Total Cost =Fuel Cost + Time Cost*

Minimum fuel ECON


ECON Cruise

Time Cost ($/hr) = CTFuel Cost ($/lb) = CF

TimeCost($/hr)FuelCost(¢/lb)CI = =

CT100 ∗ CF


ECON Cruise

TOTAL TRIP COST:C = CT∗T + CF∗ F

where R = Cruise Range, NAM

RaMT =

Time = T: Fuel Used = F:R

NAM/lbF =

C =CTRaM

+CFR

NAM/lb


ECON Cruise

To find M that yields minimum cost, we set dC/dM = 0:

dCdM

= 0 = −RCT

aM2 +CF

(NAM/lb)2d(NAM/lb)

dM

dCdM

= + CFR -1(NAM/lb)2

d(NAM/lb)dM

-1M2

∗CTRa


ECON Cruise

CI = aM2

100(NAM/lb)2d(NAM/lb)

dM

= − aM2

(NAM/lb)2d(NAM/lb)

dMCTCF

= CI ∗ 100

= − CF(NAM/lb)2

d(NAM/lb)dM

CTaM2


ECON Cruise

Mach

Fuel Mileage -NAM/lbF

0 100200

ECON Cruise Mach

MRC

300

IncreasingWeight

ConstantAltitude


Cost Index As A Function Of LRC, MRC

767-200 JT9D-7R4D


Economy Cruise Speed

767-200 JT9D-7R4D


(757)

1550 (767)

1555 (777)

90150

Typical Cost Indices For Boeing Airplanes

Cruise mach number

Fuel mileage(miles per gallon)

Typical airline values

1030

(747)

0

0

0

0

MRC

0 2580

70

80

180

35

LRC

140

(737)


Cost Comparison Between Different Airplanes

For both airplanes, assume:

• MRC = 0.77 Mach, LRC = 0.80 Mach

• FM variation with Mach is the same

• Cost of time = $600/hr

• Cost of Fuel = $300/ton (15¢/lb)

• “Large” Airplane FM = 0.05 NAM/lb @ MRC

• “Small” Airplane FM = 0.08 NAM/lb @ MRC



To obtain lowest cost (ECON) operation, should these two airplanes be flown at the same Cost Index?

Will that Cost Index result in the same ECON Machnumber for the two airplanes?



Cost index = Time-related cost ($/flight-hour)Fuel cost (cents/pound)

Cost index =$600/hr15¢/lb = 40



0.0400

0.0500

0.0600

0.0700

0.0800

0.0900

0.76 0.77 0.78 0.79 0.8 0.81 0.82 0.83Mach

Fuel Mileage

Smaller Airplane

Larger Airplane

MRC LRC



MRC LRCMach No. 0.76 0.77 0.78 0.79 0.8 0.81 0.82 0.83Fuel Mileage factor (both airplanes) 0.999 1.000 0.999 0.996 0.990 0.982 0.972 0.960Cost Index 40Cost of Time ($/hr) 600Fuel Cost ($/lb) 0.15Large Airplane FM NAM/LB F 0.0499 0.0500 0.0499 0.0498 0.0495 0.0491 0.0486 0.0480Small Airplane FM NAM/LB F 0.0799 0.0800 0.0799 0.0796 0.0792 0.0786 0.0778 0.0768

Time for 1000 NAM Cruise Segment (hr) 2.28 2.25 2.23 2.20 2.17 2.14 2.12 2.09Time Cost ($) $1,371 $1,353 $1,335 $1,319 $1,302 $1,286 $1,270 $1,255Large A/P Fuel Cost ($) $3,003 $3,000 $3,003 $3,013 $3,030 $3,054 $3,086 $3,125Small A/P Fuel Cost ($) $1,877 $1,875 $1,877 $1,883 $1,894 $1,909 $1,929 $1,953

Larger Airplane Total Cost ($) $4,374 $4,353 $4,339 $4,332 $4,332 $4,340 $4,356 $4,380Smaller Airplane Total Cost ($) $3,248 $3,228 $3,213 $3,202 $3,196 $3,195 $3,199 $3,208



Small Airplane Trip Cost

3,150

3,200

3,250

0.76 0.77 0.78 0.79 0.8 0.81 0.82 0.83Mach

Trip Cost ($)

Min Cost Speed

for CI = 40

M.807



Larger Airplane Trip Cost

4,300

4,350

4,400

0.76 0.77 0.78 0.79 0.8 0.81 0.82 0.83Mach

Trip Cost ($)

M.795

Min Cost Speed

for CI = 40


ECON Cruise

Cost Index is entered on the Performance Initialization (PERF INIT) page:

Cost Index = 0 Minimum Fuel

Cost Index = Max Minimum Trip Time


Required Time of Arrival (RTA)

FMC internally iterates on Cost Index to meet specified arrival time constraint at a given waypoint...


Enroute Cruise: Summary

• To maximize range OR minimize trip fuel for a given range, maximize fuel mileage

• Fuel mileage is affected by both altitude and speed selection

• Best Fuel mileage is attained at MRC, Optimum Altitude

• To minimize cost, calculate a Cost Index based on actual costs, and fly ECON Mach


• Do problem 20 – Factors that effect fuel mileage

CL, Page 81

FLIGHTOPERATIONS

ENGINEERING


Enroute Descent


Enroute Descent Modes

• “Strategic” Modes– Min Fuel Minimize descent fuel CI = 0– Min Time Minimize trip time CI = max– Min Cost Minimize descent cost CI = K

• “Tactical” Modes– Engine inoperative Maximize R/D Best L/D

driftdown– Emergency Maximize R/D VMO/MMO

Mode Constraint Speed


Descent Speed Selection

A constant Mach/KCAS descent schedule is typically chosen, like in climb. These speeds are chosen to approximate the precise theoretical speed for any given mode.


Additional ConsiderationsSpeed Constraints

FAR 91.117

Aircraft speed.

(a) Unless otherwise authorized by the Administrator, no person may operate an aircraft below 10,000 feet MSL at an indicated airspeed of more than 250 knots (288 m.p.h.).

•••

(d) If the minimum safe airspeed for any particular operation is greater than the maximum speed prescribed in this section, the aircraft may be operated at that minimum speed. (e.g. Heavy-weight 747-400)


Flight Management System (FMS)Control Display Unit (CDU) Descent Page


ECON Descent

Cost Index is entered on the Performance Initialization(PERF INIT) page:

Cost Index = 0 Minimum Fuel*

Cost Index = Max Minimum Trip Time

*Note: Descent is planned as much as possible at idle descent. Because speed effect on descent fuel is very small, higher descent speeds will be seen for smaller increases in CI


ECON Descent

Cost must be evaluated between two common points:

Distance

Altitude

Final Cruise Altitude

Cost IndexIncreasing

A

B

Min fuel

Min tim

e


Descent Physics

Wco

sγ

Wsinγ

γ

DragFN

Lift

Weight

γVelocity

R/D = = V sin γdhdt

dVdt

Wg

dγdt

Wg V


Sign ConventionFor descent analysis, we need to choose a sign convention:

Remember also that idle thrust for high bypass engines may actually be negative; this means that at very low power settings, the engine actually produces drag rather than thrust...

If we redefine the convention, such that γand rate of descent are positive values, then we must account for the sign convention change in our equations...

If we retain the sign convention from climb, then the resulting equations are identical, but flight path angle, γ, and rate of “descent” will be negative...

If we redefine the convention, such that γand rate of descent are positive values, then we must account for the sign convention change in our equations...

γ

DragFN

Lift

Weight

dVdt

Wg

dγdt

Wg V

γVelocity

R/D = = V sin γdhdt


Summation of ForcesPerpendicular to the Flight Path

F = Ma

Wco

sγ

γ

L

W

dγdt

Wg V

∑F = L – W cosγ = Ma = Wg

V dγdt


Summation of ForcesPerpendicular to the Flight Path

* For most applications, γ is sufficiently small that the assumption of L = W is acceptable

continued

∑F = L – W cosγ = Ma = Wg

V dγdt

is the acceleration perpendicular to the direction of flight due to changing flight path angle. For steady descent, typically it is acceptably small to be considered zero, so:

Wg

V dγdt

L = W cosγ


Summation of ForcesParallel to the Flight Path

F = Maγ

W

∑F = T – D – W sin γ = Ma = Wg

dVdtWsinγ

DT

dVdt

Wg



Solving for sinγ:

continued

∑F = T – D – W sin γ = Ma = Wg

dVdt

sin γ = T − DW

1g

− dVdT



Rate of descent = Vsinγ, so:

Rearranging:

continued

R/D = = Vsinγ = Vg

dVdt−V(T – D)

Wdhdt

Vg

dVdt=V(T – D)

Wdhdt+



continued

Vg

dVdt=V(T – D)

Wdhdt+

Substituting , yields:dVdt

dVdh= dh

dt

Vg

dVdh=V(T – D)

Wdhdt

dhdt+ dh

dt= Vg

dVdh1 +



Solving for Rate of Descent, R/D:

continued

*Note: Acceleration Factor is the same for descent and climbVg

dVdh1 +

R/D = =

V(T – D)Wdh

dt Vg

dVdh1 +


Geometric Descent Angle

• Headwind will steepen the goemetric descent angle

• Tailwind results in a shallower angle

γgeometric =R/DVg


FMC Descent Calculations

The FMC then constructs a geometric path based on the following parameters:

Final Cruise Altitude

• Desired Descent Speed,

• Idle Thrust, whenever possible

Waypoint with Altitude Constraint

The FMC will plan a descent with throttles at idle for as much of the descent as possible…

FMC Solves forTop of Descent

γ


•Low speed may require that throttles be advanced (the autothrottle will do this if engaged and speed decays enough)

•High speed may result in “DRAG REQUIRED”CDU message, prompting crew to extend speedbrakes

FMC Descent Guidance

The FMC permits descent to be flown in two different control modes. They are called “Path Descent” and “Speed Descent”

In a Path Descent, the FMC controls the airplane’s pitch to maintain the previously determined flight path (γ).

The airplane’s speed is not controlled directly, and pilot intervention may be required to maintain the desired speed

γ

DragFN

Lift

Weight


Path Descent CDU Display

Waypoint with Altitude Constraint

Desired descentspeed schedule

Actual flight path angle(γ actual)

Vertical bearing(γ required)

and correspondingvertical speed

Vertical deviation from desired path


FMC Descent Guidance: Speed Descent

In a Speed Descent, the FMC controls the airplane’s pitch to maintain the desired speed (Mach/KCAS).

The airplane’s vertical path is not controlled directly, and pilot intervention may be required to maintain the desired path...

γ

Lift

Weight

DragFN


Speed Descent CDU Display

Vertical deviation from desired path


Refining FMC Descent Predictions

Transition Level(QNE to QNH)

Descent winds array: direction/magnitude at up to three altitudes

Altitude band for anti-ice usage

Temperature deviation from

ISA and destination QNH


Driftdown

General: In the event of an engine failure in cruise flight, the maximum altitude at which the airplane can fly will be reduced.

When terrain is a factor, it may be advantageous to fly as high as possible for the greatest possible distance...


Driftdown

Procedure:

Set Maximum Continuous Thrust, and decelerate from cruise speed to maximum gradient speed: (minimum angle of descent)…

Most airplanes will not be able to maintain cruise altitude, and will drift down. The airplane will level out when thrust equals drag

continued

γ =

(T – D)W

Vg

dVdh1 +

≈Vg

dVdh1 +

TW

DL−


Driftdown Profile

2) Maintain level flight, decel to driftdown speed...

4) Choose from the following:

A Maintain speed and climb asfuel burns off

A

1) Set MCT thrust

Engine Fails...

B

B Maintain level flight and accelto EOLRC speed gradually

C

C Descend and accel to EOLRCspeed immediately

3) Maintain driftdown speed...


CDU Display for Driftdown

Engine InoperativeMaximum Altitude at current weight

Recommended Driftdown Speed

Maximum Altitude is based on bleed configuration of

operating engine

Limit Power Setting


Driftdown Regulations

FAR Part 25 defines the legal flight path…

FAR Part 121 defines the terrain clearance requirements


Net Flight Path - FAR 25.123

FAR Part 25.123 requires that the actual airplane climb performance be calculated in the most conservative airplane configuration and then further decreased by the following gradient conservatisms:

One-engine inoperative net flight path requirement

1.1% for two engine airplanes1.4% for three-engine airplanes1.6% for four-engine airplanes

Two-engine inoperative net flight path requirement

0.3% for three-engine airplanes

0.5% for four-engine airplanes

Gross (actual)driftdown flight path

Net driftdown flight path*

* The enroute net flight path is used to ensure enroute terrain clearance


Enroute Limitations - One Engine InoperativeSec. 121.191 Airplanes: Turbine Engine Powered: En Route Limitations: One Engine Inoperative.

Date: January 1, 2000

(a) No person operating a turbine engine powered airplane may take off that airplane at a weight, allowing for normal consumption of fuel and oil, that is greater than that which (under the approved, one engine inoperative, en route net flight path data in the Airplane Flight Manual for that airplane) will allow compliance with paragraph (a) (1) or (2) of this section, based on the ambient temperatures expected en route:

(1) There is a positive slope at an altitude of at least 1,000 feet above all terrain and obstructions within five statute miles on each side of the intended track, and, in addition, if that airplane was certificated after August 29, 1959 (SR 422B) there is a positive slope at 1,500 feet above the airport where the airplane is assumed to land after an engine fails.

(2) The net flight path allows the airplane to continue flight from the cruising altitude to an airport where a landing can be made under § 121.197, clearing all terrain and obstructions within five statute miles of the intended track by at least 2,000 feet vertically and with a positive slope at 1,000 feet above the airport where the airplane lands after an engine fails, or, if that airplane was certificated after September 30, 1958 (SR 422A, 422B), with a positive slope at 1,500 feet above the airport where the airplane lands after an engine fails.


Enroute Limitations - One Engine InoperativeFAR Part 121.191 continued:

(b) For the purposes of paragraph (a)(2) of this section, it is assumed that-

(1) The engine fails at the most critical point en route;

(2) The airplane passes over the critical obstruction, after engine failure at a point that is no closer to the obstruction than the nearest approved radio navigation fix, unless the Administrator authorizes a different procedure based on adequate operational safeguards;

(3) An approved method is used to allow for adverse winds:

(4) Fuel jettisoning will be allowed if the certificate holder shows that the crew is properly instructed, that the training program is adequate, and that all other precautions are taken to insure a safe procedure;

(5) The alternate airport is specified in the dispatch or flight release and meets the prescribed weather minimums; and

(6) The consumption of fuel and oil after engine failure is the same as the consumption that is allowed for in the approved net flight path data in the Airplane Flight Manual.


FAR 121.191 Paragraph (a) (1)

Distance Along Intended Track

Altitude

Airplane Gross Weight


Weight reduces dueto fuel burn off

If altitude for net positive gradient at expected enroute temperaturesclears terrain by 1000 ft then FAR 121.191 is satisfied...

Terrain within 5 statute miles of intended track

1000 ft agl


Or FAR 121.191 Paragraph (a) (2)

Terrain within 5 statute miles of intended track

2000 ft agl

Normal all-engine cruise alt

Critical Engine Failure Point

Airplane Gross Weight


Weight reduces dueto fuel burn off


Altitude


Driftdown Data in Documents

Airplane Flight Manual• Enroute climb speeds - 1 and 2 engines inoperative• Enroute climb gradient – 1 and 2 engines inoperative• Enroute climb weights - 1 and 2 engines inoperative

Operations Manual/FPPM• QRH - Speeds and gross level-off altitude• Dispatch data in OM/FPPM: Driftdown profile charts

Net level off heightETOPS net level off height

INFLT Software• Driftdown profiles can be calculated at any speed...


Enroute Climb Speed


Enroute Climb


Enroute Climb Weights

AFM Chart


OM: Performance Inflight


FPPM Driftdown

FPPM Chart


FPPM Driftdown (Partial)


Example Driftdown Profiles

0

5000

10000

15000

20000

25000

30000

35000

40000

0 100 200 300 400 500 600

Distance - NM

Alti

tude

- fe

et

Gross

Net 1 hour


• Increase Drag, Increase Velocity

• Decrease Thrust

• Other?

Emergency Descent

The goal during inflight Emergency Descent is to minimize the descent time, which means maximum descent rate.

Therefore, to maximize rate of descent, we want to:

R/D = Vγ =Vg

dVdh1 +

(T – D)WV


Emergency Descent

Velocity

Rate of Descent VMO/MMO

Light Weight (C

lean)

Heavy Weight (Clean)

Light Weight

(Speedbrake Only)

Light Weight (Speedbrake + Gear)


Example Driftdown/Emergency Descent

0

5000

10000

15000

20000

25000

30000

35000

40000

0 100 200 300 400 500 600

Distance - NM

Alti

tude

- fe

et

Gross

Net

Emergency

6.5 minutes


Emergency Descent:Flight Crew Training Manual

Figure 3-1 Rapid Descents

Note: If structural damage is suspected, limit airspeed and avoid high maneuvering loads

Determine new course of action

Level off at lowest safe altitude or 10,000 ft whichever is higherLong range cruise speed Speedbrakes in down detent

Notify ATCRequest altimeter settingCall out altitudes

Adjust speed and level off altitude

Announce descent

Select lower altitude on MCPSelect FLCH and extend speedbrakes

Descend straight ahead or initiate turn with HDG SEL


Emergency Descent:Flight Crew Training Manual

Rapid Descent

This maneuver is designed to bring the airplane down smoothly to a safe altitude, in the minimum time, with the least possible passenger discomfort. It is intended as a specialized case to cover an uncontrollable loss of cabin pressurization. Use of the autopilot is recommended (see Figure 3-1).

If the descent is performed because of a rapid loss of cabin pressure, crew members should don oxygen masks and establish communication at the first indication of a loss of cabin pressurization. Verify that cabin pressure is uncontrollable, and if so, determine if structural damage exists. If structural damage is suspected, limit airspeed to current speed or less. Avoid high maneuvering loads.

All recall items are to be accomplished from memory.

Perform the entry procedure deliberately and methodically. Do not be distracted from flying the airplane.

The PNF checks the lowest safe altitude, notifies ATC, and obtains an altimeter setting (QNH). Both pilots verify that all recall items have been accomplished and call out any items not completed.

The pilot not flying will call out 2,000 feet and 1,000 feet above the level off altitude.

Level off at the lowest safe altitude or 10,000 feet whichever is higher. Lowest safe altitude is the Minimum Enroute Altitude (MEA), Minimum Off Route Altitude (MORA), or any other altitude based on terrain clearance, navigation aid reception, or other appropriate criteria.

When turbulent air is encountered or expected, reduce to turbulent air penetration speed (280 KIAS or .84 Mach above FL250; 270 KIAS below FL250).

Rapid descent is made with the landing gear up. If icing conditions are entered, use engine anti-ice.

continued


FAA requirementsDependent on airplane type


FAA requirementsDependent on airplane type


JAA requirementsDependent on airplane type


JAA requirementsDependent on airplane type


Method of Calculating Descent/Driftown Time, Fuel, and Distance

1. Determine altitude integration step h1 to h2

12. For multiple altitude steps, sum the total of ΔFuel

11. Determine delta fuel for the step

10. Determine the fuel flow at average altitude, Wfavg

9. For multiple altitude steps, sum the total of delta distances

8. Calculate incremental distance for the step

7. Calculate average true airspeed over the step Vavg

6. For multiple steps, sum the total of delta times

5. Calculate delta time for the step

4. Calculate average rate of descent at the altitude havg

3. Calculate Δh for the step

2. Calculate average altitude for step havg = ( h2 + h1)/2

Δh = h2 − h1

Δhr/davg

Δt =

Δt x Vave

60ΔNAM =

Δt x Wfavg60ΔFuel =


Integrating to Calculate Descent or Driftdown Performance

Given: Top of Climb WeightSpeed ScheduleClean Configuration

H1p to H2p

(1)Select

havg

(2)Average

Δh

(3)H2 - H1

r/davg

(4)Calculate

Δt

(5)(3) + (4)

Sum of Δt

(6)

Vavg

(7)Calculate

Sum ofΔNAM(9)

Wfavg(10)From

EngineData

(12)

Sum of ΔFuelΔNAM(8)

(9) x (7)60

ΔFuel(11)

(5) x (10)60


Distance - NAM

Pressure Altitude

Fuel - kgTime - Hours

• Idle Thrust, • Constant ISA deviation

Increasing weight

Weight Effect on Descent


Descent Presentation (FPPM)


Descent Presentation (OM PI)


• Do Problem 21.


Descent and Driftdown Summary

• Looked at descent speed selection and physics of common “tactical” and “strategic” objectives

• Primary method of calculation is by step integration

• Reviewed FMC Descent calculations and guidance


25. True or False, the faster the enroute climb speed the less fuel burn.

False, there is an optimum speed for climb efficiency. This speed is typically around cost index of 0

26. True or False, Cost Index can be different on different routes.

True, each airline computes cost index based on their cost and route structure. Some airlines work this very hard including a different cost index on different routes, time of day etc.


27. True or False, the higher the airplane flies the better theairplane efficiency.

False, there is an optimum altitude which is based on a combination of the airplane Aerodynamics and the engine efficiency. There is also the influence of wind which may change which altitude is optimum.

28. True or False, it is best to slow down and drop the gear for the quickest emergency descent.

True and False, typically the quickest emergency descent can be obtained by flying the highest speed to maximize rate of descent but on some airplanes like the 747 a higher rate of descent can be achieved by slowing down and dropping to gear. The gear drag increase of sets the lower speed and less airframe drag.


29. True or False, an emergency descent should always be flown at the highest speed possible.

False, in general the optimum rate of descent and therefore minimum time in descent is at the highest speed but if there is a question of structural integrity accelerating to higher speed may make it worse. In these cases it is not recommended to increase speeds.

L, Page 1

FLIGHTOPERATIONS

ENGINEERING


Landing

L, Page 2For Training Purposes Only Copyright © 2009 Boeing. All rights reserved

Landing Performance


Landing Performance Considerations


Landing Performance Considerations

• Field length requirements– AFM– Operational

• Brake energy requirements– Quick turnaround– Brake cooling

• Climb requirements


Field Length

Flare - 50 feet to touchdown

Transition - touchdown to full braking configuration

Full Braking Segment - full braking configuration to stop

VAPP =VREF = 1.23 VS 1-G or 1.30 VS FAR

TransitionFlare Full Braking Segment


Air Distance - Flare - 50 feet to Touchdown

• Certified - FAA AFM

– Measure time from 50 feet to touchdown– Numerous landings targeted at 4 - 6 ft/s touchdown rate – Resultant time 5 - 6 seconds

– Per AC 25 - 7 data is corrected to a touchdown rate of 8 ft/s– Resultant time 4.3 - 5 seconds depending on model– One certified value of time

– Air Distance = Flare Time50-TD x Vavg 50-TD



• Certified - JAA AFM– Same as FAA for dry runway data– Contaminated runway is based on 7 seconds

per JAR guidance material


Speed Bleed Off During Flare

• Approach at VREF, touchdown at lower speed due to speed bleed off

• FAA, JAA AFM dry/wet, “FAA/JAA” operational dataVTD / VAPP = 0.99

• JAA Cert for contaminated/slippery data (7 second flare)VTD / VAPP = 0.93

~


Example – Certified Air Distance Calculation

• Example: Assume Vref = 131 ktas and VTD / VAPP =0.982 therefore VTD = 128.6 ktas– Flare Time50-TD is 4.2 seconds – Vavg 50-TD = 129.8 ktas– No wind

• Air Distance = 4.2 s ∗ 129.8 kts gs ∗1.6878 ft/S/kt= 920 feet



• Operational - Slippery runway, non-normal– “FAA” airlines operational data uses a fixed

distance for flare– 737, 757, 767, 777 - 1000 feet– 747 - 1200 feet

– JAROPS operational data uses a fixed distance for flare– 737, 747, 757, 767, 777 - 1000 feet


Transition

• Requirement, demonstrated flight test time or one second, whichever is longer for each manual action– Actions - apply wheel brakes, manual spoilers– Are allowed to take credit for automatic spoilers

Transition

TouchdownFull brakingConfiguration


Velocity

Time - Sec

Touchdown

0 1 2

Auto spoilers, manual braking ~ 0.98 - 0.99

Manual spoilersManual braking ~ 0.97 - 0.98

Note: Actual data not linear

Speed Bleed Off After Touchdown - VB / VTD


Full Braking Segment

• Maximum manual braking on a dry runway

• No reverse thrust

• Flight test, measure stopping distance and solve for brake force required to stop the airplane in the measured stopping distance

Full Braking Segment


Ground Deceleration Capability


FSlope Drag

ThrustForward – idleReverse – spinup, detent, max

Retarding Force due to Wheel Brakes



Thrust − Drag − Brake Force − Fslope = Mass ∗ Accel

T − D − μB ( W - L ) − Wsin Φ = aWg

small angles sin φ = φ in radians

T − D − μB ( W - L ) − W Φ = aWg



Auto-spoilersVTD/VAPP = 0.98VB/VTD = 0.99

Sample Calculation of Deceleration

a = [ T − D − μB ( W − L ) − W Φ ]gW

Sample deceleration calculation

SLOPE = 0WIND = 0Weight = 198,000 lb

Spoilers up:CD = 0.2293 μB = 0.3701CL = 0.134

299113-6.3-10.6073280198000000.0083040297840-6.3-10.6073247197911891510.34793710293865-6.4-10.80731491976463546061.35757020287390-6.5-10.907298519720379713633.057204302783114-6.6-11.1072756196584141624235.426837402669137-6.7-11.3072461195787221337868.466470502532157-6.9-11.60721011948143186545312.196195602375177-7.1-11.90716751936634337742216.595920702198195-7.2-12.20711831923355665969321.675646802003211-7.5-12.607062719083171691226827.425371901792227-7.7-13.007000418914988511514633.8650961001565241-7.9-13.4069316187290107101832740.9748811101324188-8.2-13.9068563185254127462181048.7546661201136216-8.5-14.3067954183611143892462255.044505127.592092055.99128.6058.10131

TotalDistanceDistanceAccel

(kts/sec)Accel

(ft/sec2)Force SlopeFBW-LLiftDragDynamic

PressureTotal

ThrustGround Speed

Touchdown

Full Braking(1 second later)

920216


Sample Landing Distance Calculation

• Air Distance - 920 feet (earlier example)

• Ground Distance - 2071 feet (transition + full braking configuration, previous page)

• Total landing distance for this example920 + 2071 = 2991 feet


Factors Effecting Stopping Distance

• Thrust– 5 second after touchdown high idle,

then spindown to ground idle– Why ?– Reverse thrust - good

• Brake Force– Slippery runway, tire to ground friction– Load on the gear, ground spoilers

• Drag, more drag is good


Factors Effecting Stopping Distance

• Speed– Higher approach speed more distance

– Example 737-800 has increased flaps 30 and 40 approach speed for tail clearance.

• Wind - headwind good, tailwind bad

• Slope - uphill good, downhill bad

• Temperature, Altitude

• Inoperative equipment


Brake Force Generalization - Dry runway

FB ,BrakeForce

W - L

Average Weighton Wheels

WVBg2



W - LμB = = Constant

Torque Limited RegionFB = Constant

Fade Region

Note: Level may be different than takeoff

Dry Runway Performance - Maximum Manual Braking


FAR Landing Field Length

• Turbine powered airplane must be capable of coming to a full stop within 60% of the available runway

• Another way of saying this is that the demonstrated landing distance must be increased by 67% (multiplied by 1.67)


Full Stop

60 % of available runway


FAR Wet Landing Distance

• FAR wet landing distance is the dry increased by 15 % -no testing required

• There is an alternate means of compliance

60 % of available runway1.67 times demonstrated distance

15 %for

Wet


Full Stop


AFM Type Example Distances

• From previous example - Calculated distance is 2991 feet

• FAR Dry distance is 1.67 ∗ calculated distance– Example: 2991 ∗ 1.67 = 4994 feet

• FAR Wet distance is 1.15 ∗ FAR Dry– Example: 4994 ∗ 1.15 = 5744 feet


Sample FAR Landing Field Length Chart

Field Length

Field LengthLimited Weight

Altitudes0246

Wind

Reference Line

Wet

Dry

Reference Line


Factors Effecting AFM Landing Distance

• Thrust ?

• Brake Force / Brake Category

• Lift / Drag - Flap Setting

• Speed - Flap Setting, all calculations at VRef

• Wind - headwind good, tailwind bad

• Altitude

• Temperature ?

• Slope ?


Operational Landing Distance Information

• Boeing provides operational landing data for non-certified conditions– Slippery runway - good, medium, poor– Non-normal configurations– Auto brake information

• Data is not certified - Advisory information– Non-factored

• JAR-OPS 1 requires 1.15 factor on advisory slippery runway data

• FAA SAFO 06012 - August 2006– Safety Alert For Operators– Voluntary compliance


SAFO 06012“Survey Findings”

• Documents FAA finding that some airlines:

– have misused or misinterpreted the information the manufacturer supplied.

– have not revised their documents and methods when manufacturer has made revisions.

– did not train or provide guidance on how to use operational landing distance information provided by manufacturer nor address safety margins.

– did not include manufacturer data in operations procedures.

– did not require landing distance assessments at time of arrival.

– had confusion on whether reverse thrust has been included in the calculations


SAFO 06012Recommendations

• Recommends enroute evaluation of landing performance if actual conditions are worse than dispatch calculations.

• Recommends margin of Safety of at least 15% in non-emergency situations.

• Provides definitions of Braking Action terminology–Industry working group has created a voluntary set of

definitions and explanations to be used in operation and as a starting point for future rulemaking.

• States 1000 feet air distance is not consistently achievable.

• Provides a method of compliance based on normal AFM dry runway data

• States “All flight crewmembers must have hands-on training and validate proficiency in these procedures …..” referring to how to use the airlines slippery runway data to evaluate landingperformance


Slippery Runway

• On slippery runway tire to ground friction is reduced due to contaminant– Snow, Ice, Slush

• Boeing provides data two ways– PEM - Airplane Braking Coefficient - Graphic– OM - good, medium, poor - tabular

• Data is unfactored and takes credit for reverse thrust– Wet - Good, μB = 0.2– Wet Ice - Poor, μB = 0.05


Deceleration Available from BrakesDeceleration Available from Brakes

Maximum Deceleration Available from Brakes

Max BrakesMax

Brakese.g.

stand on the brake pedals

e.g.stand on the brake pedals

Dry

Antiskid limitedAntiskid limitedGood

Med

Poor

Runway conditionBraking action

WorseWorse

BetterBetter

Braking Conditions

Braking Conditions

Antiskid limitedAntiskid limited

Antiskid limitedAntiskid limited

MoreMoreLessLess



JAA books contain 1.15 factor.

•At this point FAA books will not be changed due to SAFO 06012•SAFO is not a regulatory requirement


Non-normal Configuration

• Equipment fails inflight which effects landing distance– Higher approach speed ? - slat/flap failure– Reduced braking - hydraulic system problem– Advisory tabulated data in the OM



Autobrake

• Autobrake controls stop to a programmed deceleration rate– Pilot chooses autobrake setting 1, 2, 3, Max – Each auto brake setting has a programmed

deceleration rate – For example 1 might be 4.0 ft/s2, 2 might be

6.5 ft/s2

– Brake pressure required to meet deceleration rate is applied by autobrake system


BrakesDrag

BrakesDrag

BrakesDrag

BrakesDrag

Deceleration Max Manual Versus Autobrakes

DecelerationDeceleration MoreMoreLessLess

Braking Applied

Max Manual

Autobrake Max

Autobrake 2

Reverse Thrust

Reverse ThrustBrakesDrag

BrakesDrag

Dry runwayDry runway

Target deceleration

Target deceleration

Deceleration level achieved

Distance based on autobrake decel rate

Reverse Thrust


Autobrake Calculation Example

Initial speed = 130 kts ground speedAssume deceleration rate is 4.0 ft/s2

Note: Short transition section is added to account for initial ramp up of brake pressure.

VΔVaDistance =

Distance = 6017 feet

VΔVa

65 ktgs (130 − 0)ktgs ∗ (1.688 ft/s/kt )2

4.0ft/s2Distance = =


Autobrake Ramp Up Example

Brake Pressure(PSI)

Time from Touchdown - Sec0 1 2 3 4

100 PSI/S1

2

3

Max

AutobrakeSetting

450 PSI/S

1400 PSI/S


Autobrake Deceleration Example

Airplane DecelerationFt/Sec2

Time from Touchdown - Sec0 1 2 3 4

1

2

3

Max

AutobrakeSetting

13.0

7.2

5.1

4.0


Sample Brake Pressure During the Stop

Brake Pressure(PSI)

Time from Touchdown - Sec

1

Max

AutobrakeSetting

Reverse thrustapplication


Deceleration Available from Brakes

Maximum Deceleration Available from Brakes

Max Brakes

e.g.stand on the brake pedals

Dry

Antiskid limitedGood

Med

Poor

Runway conditionBraking action

Worse

Better

Braking Conditions

Antiskid limited

Antiskid limited

MoreLess


DecelerationDeceleration MoreMoreLessLess

Braking Applied

BrakesDrag Reverse Thrust

BrakesDrag

BrakesDrag Reverse Thrust

BrakesDrag

BrakesDrag

BrakesDrag

Autobrake on slippery runway“Good” braking action

Deceleration level achieved

Distance based on autobrake decel rate

Deceleration level NOT achieved

Distance based on runway friction

Max Braking AvailableMax Braking AvailableDry

MedPoor

Good

Max Manual

Autobrake Max

Autobrake 2 Reverse Thrust Target

decelerationTarget

deceleration


Brake Energy Requirements

• Quick turnaround

• Brake cooling

• Maximum brake energy requirements– Brake integrity– On some models Brake Energy information has been

supplied in the PEM for non-normal landing– Higher approach speeds, for example, flaps up landing


0

200

400

600

800

1000

1200

1400

0 20 40 60 80 100Time from start of stop - Minutes

Temperature (F)

Center Stator

BrakeTemperature Monitor

Wheel Thermal Plug (Fuse Plug)

Example 747 Stop - 30 Million Ft-lbsTime-Temperature History


Quick Turnaround

• During stop, internal friction of the rotors and stators cause brake heating

• The temperature rise in the brakes will dissipate throughout the wheel

• Quick Turnaround Requirement is a requirement which addresses the increase of temperature in the wheels


Quick Turnaround

• Wheel Thermal Plug (fuse plug)– Piece of metal in the side of the wheel which will

melt if the temperature of the wheel gets too high– Purpose thermal plug is to protect against an

explosive release of tire nitrogen



Maximum Quick Turnaround Weight

• Maximum Quick Turnaround Weight – Maximum landing weight which will meet the wheel

thermal plug (fuse plug) no melt requirement– Assumptions

– Approach at VRef

– Maximum manual braking on a dry runway to a complete stop

– No reverse thrust


Maximum Quick Turnaround Weight

• If weight is less than or equal to the maximum quick turnaround weight, then there isn’t a time restriction on when subsequent takeoffs can occur

• If weight is greater than maximum quick turnaround weight:– The airplane must stay on the ground for the specified

amount of time or

– Meet an alternate compliance method where the temperature of the wheel brake is measured



Maximum Quick Turnaround Time

• Highlighted note from quick turnaround chart– After landing at weights exceeding those shown above,

adjusted for slope and wind, wait at least 67 minutes and check that wheel thermal plugs have not melted before executing a takeoff.– This time only addresses wheel fuse plug melt issues – The time does not imply that the brakes will have cooled

down sufficiently to absorb the energy of an RTO– Time dependent on airplane, wheel, brake configuration


Maximum Quick Turnaround Time

• Highlighted note from quick turnaround chart– As an alternate procedure, ensure each brake

pressure plate temperature, without artificial cooling is less that 218º C …………If each measured temperature is less that 218º C, immediate dispatch is allowed.


Brake Cooling

• Assumptions for quick turnaround do not address every day operating variables– Speed above Vref– Use of autobrake– Use of reverse thrust– Taxi distance– Delayed braking– Less than maximum brake force use– etc.



Brake Cooling Chart

• Brake cooling chart provides recommended cooling times to decrease the residual brake energy to a level low enough to avoid tire deflation on subsequent landings

• Times do not ensure that the brakes will be cool enough to absorb the energy resulting from a high energy RTO


Landing Climb Requirements

• FAR requirements– Approach Climb– Landing Climb– Other


Landing - Climb Calculation

Approach Climb• Approach Flap • 2 eng – 2.1%• Gear up • 3 eng – 2.4%• Engine inoperative Go-around thrust • 4 eng – 2.7%

Landing Climb• Landing flap• Gear down• All Eng thrust available after 8 s.• All airplane 3.2 %


Climb Calculation

• Calculate weight which meets approach climb requirement

• Calculate weight which meets landing climb requirement

• Compare - lowest is Landing Climb limited weight– Point calculation - capability not operational


Landing Climb - Calculation Basis

• Stall speed in approach configuration may not be more that 1.1 times the stall speed in landing configuration - paired flap

• Speed for calculation– Approach climb

– Not to be greater than 1.5 Vs FAR / 1.4 Vs 1g

– Landing climb– Not to be greater than 1.3 Vs FAR / 1.23 Vs 1g

• Speed for maximum gradient is typically used




JAR-OPS 1.510(b)

The missed approach procedure of an instrument approach as shown on instrument approach charts is normally based on an obstacle clearance surface having a slope of 2.5%. This cannot be achieved by all aeroplanes when operating at or near maximum certificated landing mass and in engine-out conditions. Operators of such aeroplanes should consider mass, altitude and temperature limitations and wind for the missed approach at aerodromes which are critical due to obstacles in the missed approach areas. An increase in the decision altitude/height or minimum descent altitude/height may, as a result, be required.


• At some airports the allowable minimums are a function of airplane climb capability

400 ft

200 ft


True, this data is provided for evaluation of the runway conditions at the time of landing. The airline/flight crew should ensure there is adequate margin to conduct a safe landing by evaluating all of the pertinent information or airline policy.

True. A correction is also provided for no reverse thrust operation.

30. Boeing provides actual (non-factored) Advisory slippery runway data in the FAA OM PI section of the OM for decision making purposes. (True/False)

31. This actual (non-factored) Advisory slippery runway data in the FAA OM PI section takes credit for reverse thrust in the calculation of the stopping distance. (True/False)


32. This actual (non-factored) Advisory slippery runway data in the FAA OM PI section represents the airplane’s capability if every thing is as assumed in the calculation, touchdown on the numbers, immediate use of reverse thrust etc. and the airline/flight crewshould ensure the runway has adequate margin for the specific operation. (True/False)

True, this is the airplane capability and the airline/flight crew need to determine the actual conditions and determine if adequate margin exists.


33. The autobrake system is capable of achieving the programmed decel rate on a slippery runway with out the use of reverse thrust. (For example, assuming the use of Autobrake setting 3, can the airplane stop in the same distance on an icy runway as a dry runway.) (True/False)

False, the autobrake attempts to reach the programmed decel rate by applying more and more brake pressure. However, on a slippery runway the antiskid system will limit the amount of pressure which will get to the wheel brakes to prevent tire skidding. On a slippery runway it is very possible the combination of reverse thrust and maximum wheel braking (as limited by the antiskid) will not be adequate for the airplane to reach the target decel rates.


34. The use of reverse thrust is required to obtain the published advisory slippery runway distances in the OM. (True/False)

35. The AFM climb gradient calculations for landing ensures the airplane can climb at 3.2% gradient at landing flaps with a gear down and an engine inoperative. (True/False)

True, corrections are included to remove the effect of reverse thrust.

False, the AFM climb gradient calculations for landing ensure the airplane can climb at 3.2% gradient at landing flaps with a gear down at the all engine thrust available after 8 seconds.

IN, Page 1

FLIGHTOPERATIONS

ENGINEERING


Introduction to Navigation

IN, Page 2For Training Purposes Only Copyright © 2009 Boeing. All rights reserved

Introduction To Navigation

• Methods and Equipment

• Procedures

• Navigation and the FMC


Navigation

• Knowing:– Where you are– Where you want to go– About how much fuel and time it will

take to get there



Pilotage

Identification of present position and direction of flight by visual contact with terrain


Latitude and Longitude

• Measured in degrees, minutes, seconds

• Latitude refers to “parallels”, and is measured north or south of the equator (90° south to 90° north)

• Longitude refers to “meridians”, and is measured east or west of the Prime Meridian passing through Greenwich, England (180° west to 180° east)

One minute of latitude, measured on the earth’s surface, is equal to one nautical mile.

• 60 minutes equals 1º• 60 seconds equals

1 minute


Latitude and Longitude

N47°27’51”

W122°14’05”

continuedRight now, you are here

Note: Lat/Long in FMC’s is most often displayed in Degrees, Minutes and Decimal minutes (e.g. N47°27.9 W122°14.1)Note: Lat/Long in FMC’s is most often displayed in Degrees, Minutes and Decimal minutes (e.g. N47°27.9 W122°14.1)


Dead Reckoning

• Application of laws of physics to estimate position

• Calculation of basic flight parameters necessary to safely get from point A to point B

• Basis for air navigation

TRACK and GRND SPD

HEADING + TAS

WIN

D


HEADING Versus TRACK

• Heading - direction airplane is pointed

• Track - direction airplane is moving

HEADING

TRACK


MAGNETIC VARIATION

• There is a difference between true and magnetic north

• True North + Magnetic Variation = Magnetic North

• “East is least and west is best”


Who am I?


NON DIRECTIONAL BEACON

• Sends the same signal in all directions

• Limited operating range

• Strongly affected by weather

• Used by automatic direction finding (ADF) equipment

• Limited usage in US


VOR

• Very high frequency Omnidirectional Range

• Uses two phased signals to generateradial-specific information

• Behaves like 360 different signals

• 3 letter identifier

• Limited to line-of-sight

• Sensitive to terrain interference

0

180

270

090

31545

135225

Magnetic North


Web-based VOR Tutorial

Tim’s Air Navigation Simulator:http://www.visi.com/~mim/nav/


777 Nav Display - Full VOR Mode


777 Nav Display - Expanded VOR Mode


DME

• Distance Measuring Equipment

• Required for operation above FL240

• Ultra-high frequency

11 22 33 44 55 66 77 88 99 1010 1111 1212 1313 1414 1515 1616 1717 1818 1919 2020 2121


DME Operation

• VOR is passive, no input required from plane

• DME is active, requires transmitter and receiver at each end (plane and DME)

• Plane must send a signal to DME to activate it


VOR/DME, TACAN, and VORTAC

• All have both a VOR and DME

• VOR/DME is for civilian use only

• TACAN uses same civilian DME but has a different VOR for military use

• VORTAC is a combines VOR/DME and TACAN facility, the two systems are physically located next to each other

• DME and VOR frequencies are “paired”


DME Accuracy

• Varies with each DME

• Most are accurate to within 0.2 NM at all distances

• Some are accurate to within 0.1 NM at all distances

• Least accurate are within 3% of total distance


Slant Range Error

• DME measures distance between plane and the DME, not distance along ground

• The closer the plane is to the DME the greater the “error” is

0 NM 5 NM 10 NM 15 NM

4 N

M 6.4 NM 10.8 NM 15.5 NM


Inertial Reference Systems

• Self contained

• Very accurate

• Start from a known point

• Use accelerometers and gyros to track changes in acceleration and direction

• Position updates from VOR/DME, GPS ...

• Use this information to track position


• Some airplanes have 3 Inertial Reference Units (IRUs)

• When 3 IRUs are installed, they “vote” to determine airplane position

• 2 closest “win”

Multiple IRU Installations


GPS is the most well known type of GlobalNavigation Satellite System (GNSS)

Global Positioning System (GPS)

GPS is a satellite based radio navigation system whichUtilizes precise range measurements from GPS satellites To determine precise position anywhere in the world.


GPS

• Twenty Four satellites (plus eight spares) operated by USAF provide 24-hour, all-weather, global coverage

• Satellites are equipped with atomic clocks

• Minimum of four (4) satellite signals enable receivers to triangulate position and time

• System is passive (unlimited number of users)

The System


How GPS works• Position of GPS satellites in space is known very

precisely

• GPS receiver can determine its distance from satellites

You are hereYou are here


Global Positioning System

• Minimum of 4 required to determine position, usually 8 - 10 used

• Reception of five or more permits Receiver Autonomous Integrity Monitoring (RAIM)

• Passive system, unlimited number of users


Web-based GPS Tutorial

Trimble GPS Tutorial:http://www.trimble.com/gps


GPS Error Sources

Per Satellite Accuracy Standard GPS Differential GPSSatellite Clocks 1.5 0Orbit Errors 2.5 0Ionosphere 5.0 0.4Troposphere 0.5 0.2Receiver Noise 0.3 0.3Multipath (Reflections) 0.6 0.6Selective Availability (SA) 30.0 0

Typical Position AccuracyHorizontal 50 1.3Vertical 78 2.03-D 93 2.8

Typical Error Budget (in Meters)


Instrument Landing System

• ILS 3 to 6°

3°

IN, Page 30

Outer Marker

Middle Marker

Inner Marker


777 Primary Flight Display (PFD)


BOARDING PASS

Passenger Names:Fundamentals Course Students

Seats:

Destination:San Francisco


How do we get from Seattle to San Francisco?

How do we get from Seattle to San Francisco?


Route Planning

• Can I fly direct?

• Is there an airway?

• Are there special considerations for departing and arriving at those airports


Great Circle

• Shortest distance between 2 points

• Plane between the 2 points and center of the Earth

• Dist = 60 x cos-1[sin(lat1) x sin(lat2) + cos(lat1) x cos(lat2) x cos(long2-long1)]


Departure

• SID’s or DP’s

• Standard Instrument Departure or Departure Procedures

• Set by governing authority


JET and VICTOR Airways

• Network of airway routes based on the VOR/DME system

• Victor airways below FL180 (low altitude)

• Jet airways from FL180 to FL450 (high altitude)

J 501

J 73

V 199


Approach

• STAR’s

• Standard Terminal Arrival Routes

• Set by governing authorities


Preferred Routes

• Published by flight planning services

• High and low altitude

• For Seattle to San Francisco: “J70 Elmaa J589 RBG J143 PYE”???


ELMAASIX Departure (SID)


ELMAA SIX SID (Text)

This SID requires a minimum climb gradient of 550' per NM to 3000'.

“Rwys 16 L/R: Intercept and proceed via SEA R-158, cross D5 SEA at or above 3000', then turn right to a 250°heading to intercept and proceed via SEA R-227 to ELMAA Int.”


ELMAA SIX SID (Chart)


How Does the SID Relate to the Preferred Route

• “...proceed via SEA R-227 to ELMAA Int.” “J70 ELMAA J589 RBG J143 PYE”

• SEA R-227 is J70

• J70 intersects J589 at Elmaa


Getting To KSFO

• Follow the recommended route: “J70 ELMAA J589 RBG J143 PYE”

• ELMAA Six SID got us to J589

• J589 ends at Roseburg (RBG)

• J143 starts at Roseburg (RBG)

• J143 takes us to Point Reyes (PYE)


KSFO Arrival (STAR)

Golden Gate Four Arrival(For use by turbojet aircraft only)

Arrival:From over ENI VOR via ENI R-146 and PYE R-325 to PYE VOR thence via SFO R-303 to SFO VOR. Expect vectors to final approach course.


Welcome to San Francisco


Other Airways

• North Atlantic Organized Track System

• Pacific Organized Track System


Area Navigation (RNAV)

• IRS• VOR/DME• ILS/Localizer• GPS

+

= RNAV


Area Navigation (RNAV)

Origin

Destination

RNAV

Origin

Destination

continued

Ground-basedNavigation aids


Required Navigation Performance (RNP)

“A statement of the navigation performance accuracy necessary for operation within a defined airspace.”

(International Civil Aviation Organization, ICAO)

Consists of a distance, in nautical miles, accompanied by a probability, in %


Example: RNP 10

Actual airplane location within 10 nmi of navigation system position at least 95% of the time

Desired Path

10 nm

10 nm


Example: RNP 10

Actual airplane location within 10 nmi of navigation system position at least 95% of the time

Desired Path 10 nm10 nm 95% probability


Containment limit 2 X RNP(99.999%)

Containment limit 2 X RNP(99.999%)

RNP (95%)

RNP (95%)

Route Centerline

RNP Containment Region


Reduced Separation

Optimized buffers for airspace separation

Defined PathRNP 95% ThresholdContainment Limit

Legend

60 - 100 NMMitigates Navigation errors,Navigation Performance, Route, Traffic Density, Surveillance,Communication, ATC

PLMN

4.0 NM

PWVG

RNP 4 RNAVPOPP

PLWX

4 x RNP(16 NM)

PerformanceAssuranceRegion


RNP Operations

RNP, Takeoff to Landing:

Low Visibility Takeoff

Cat II or III Landing

DepartureEnroute

ApproachCat I and II

RNP.3

RNP.5

RNP1

RNP4 – RNP12…

RNP2RNP2

RNP1

RNP.3

RNP.5 RNP.1

RNP Profile Plan View


Actual Navigation Performance (ANP)

A real-time calculation of the airplane’s estimated position error (95% probability), based on current and past navigation inputs, according to a statistical model in the Flight Management Computer

RADIO NAVAIDS

IRS POSITION

Sure could use a GPS position update

about now…


Demonstrated ANP

Examples of Minimum Demonstrated ANP’s*:

LNAV with Autopilot engaged

LNAV with Flight Director

Manual Control with Map Display

* Airplanes equipped with GPS

00.10.20.30.40.50.60.70.80.9

1

737 747 757/767 777

Demonstrated ANP (NM)



Position Initialization(POS INIT) page:

• GPS

• Ref Airport

• Gate

• Last Position


Route page 1 of 2(RTE 1/2) :

• Manual

• Company Route

• Data Link


FMC


Datalink (ACARS)


Route page 2 of 2 (RTE 2/2) :

• End Points


Departures Page

• SID’s

• Runways


Legs Page:

• Current leg shown in magenta

• Name of waypoint

• Distance to waypoint

• Speed and altitude restrictions


Arrivals Page

• STAR’s

• Approaches


Progress Page 1 of 2:

• Distance to go

• Est. time of arrival

• Est. fuel remaining


Progress Page 1 of 2 (continued):• Can check distance to and

ETA for other enroute waypoints


Progress Page 2 of 2:

• Wind, head and cross wind components

• Lateral and vertical track error

• TAS, static outside air temperature

• Fuel Quantity from Fuel Quantity Indicating System (FQIS) and as calculated by FMC


Position Report:

• Actual time of arrival and altitude at last waypoint

• ETA for upcoming waypoint

• Temperature and wind


Reference Navigation Data Page:

• Gives information about navaids

• Frequency

• Location

• Magnetic variation

• Elevation


Reference Navigation Data Page (continued):• Can also give information

on runways


Position Reference Page (2 of 3):• Page 1 is POS INIT

page• Shows calculated

airplane position


FMC Display of RNP/ANP

• FMC displays both RNP and ANP

• ANP must remain less than RNP for continued operation

• RNP-based procedures include required crew actions if ANP exceeds RNP


Mission Planning Issues

• Winds and temperatures

• Fuel requirements

• Redispatch

• Alternate planning


Wind and Temperature Statistical Data

• PCWINDTEMP

Provides statistical enroute wind and temperature information for specific great circle or waypoint routes, as a function of:

Season/month (e.g. Summer)Reliability (e.g. 85%)Cruise airspeed and altitude

Also calculates Equivalent Still Air Distance (ESAD)


Wind and Temperature Documents

• Winds on World Air Routes*

• Winds on US Domestic Routes*

• Temperatures on World Air Routes*

• Temperatures on US Domestic Air Routes*

• Airport Temperatures (CD-ROM, 2002)

* These documents not been updated since 1991, because of the release of PCWINDTEMP


Statistical Wind/temp Represents

• Single average head/tailwind or temperature that produces the same effect on flight planning as the expected variation of winds/temps during the trip

• Tailwind is defined as positive

• Probability X means wind/temp will be as predicted or better X% of the time…


Seasonal Winds/Temps

• Data can be calculated for the four seasons, individual months, or annual

• Season represents three month period (e.g. “Winter” = Dec, Jan, Feb)


Annual Winds/Temps

• Winds based on average of all four seasonal winds

• Can be calculated for any reliability


PCWINDTEMP Demo

• Seattle (KSEA) to London Heathrow (EGLL)– Cruise altitude FL350 (35,000 ft)– Mach 0.84 (= 484 KTAS)

• Calculate wind and ESAD for:– Great circle routing– All four seasons– 50%, 75%, and 85% reliability


PCWINDTEMP Results


Airport Temperatures

• Similar data available for temperatures

• Average daily minimum, maximum, and average

• Monthly, quarterly, half-yearly, and yearly


Fuel Requirements

• Is it a domestic flight?

• Is it an international flight?

• FAA?

• ICAO?

• Other?


FAA Domestic

(A) Fly to the airport to which it is dispatched

(B) Thereafter, to fly to and land at the most distant alternate airport (where required) for the airport to which dispatched; and

(C) Thereafter, to fly for 45 minutes at normal cruising fuel consumption

FAR 121.639

A B C


FAA International

(A) To fly to and land at the airport to which it is released

(B) After that, to fly for a period of 10 percent of the total time required to fly from the airport of departure to, and land at, the airport to which it was released

(C) After that, to fly to and land at the most distant alternate airport specified in the flight release, if an alternate is required; and

(D) After that, to fly for 30 minutes at holding speed at 1,500 ft above the alternate airport (or the destination airport if no alternate is required) under standard temperature conditions

FAR 121.645

AB

CD


FAA “Island Reserves”

• No alternate specified in release

• Must have enough fuel to fly to airport and thereafter to fly for 2 hrs at normal cruising fuel consumption

FAR 121.645, continued


ICAO InternationalICAO Annex 6 - 4.3.6.3

(A) To fly to the alternate aerodrome specified in the flight plan; and then

(B) To fly for 30 minutes at holding speed at 450m (1,500 ft) above the alternate aerodrome under standard temperature conditions, and approach and land; and

(C) To have an additional amount of fuel sufficient to provide for the increased consumption on the occurrence of any of the potential contingencies specified by the operator to the satisfaction of the state of the operator.(Typically a percentage of the trip fuel - 3% to 6%).

4.3.6.3 Aeroplanes equipped with turbojet engines.4.3.6.3.2 A) When an alternate aerodrome is required:to fly to and execute an approach, and a missed approach, at the aerodrome to which the flight is planned, and thereafter:

B

C

A


Basis for Redispatch

• Reserve/contingency fuel is a function of trip length or trip fuel burn

• Originally designed to cover errors in navigation, weather prediction, etc...

• Navigation and weather forecasting techniques have improved, decreasing the chance that contingency fuel will actually be used


Benefits of Redispatch

• Reduce required fuel load

• Increase payload


How Redispatch Works

Climb

Cruise

Descent

Redispatchpoint

InitialDestination

FinalDestination

Origin


Fuel Savings

Distance

Fuel required

FuelSaved

Redispatchpoint

Fuel saved


Off Track Initial Destination

RedispatchPoint

InitialDestination

FinalDestination

Origin

RedispatchPoint

InitialDestination

FinalDestination

Origin


Alternate Airports

Items to consider when choosing an alternate airport:

• Size and surface of runway

• Weather

• Hours of operation, lighting

• Facilities

• Fire fighting, rescue equipment


When Do You Need an Alternate?

• “No person may dispatch an airplane... Unless there is at least one alternate airport for each destination airport in the dispatch release, unless -

• The flight is less than 6 hours old and for at least 1 hour before and 1 hour after ETA, weather reports and/or forecasts indicate the ceiling will be:

FAR 121.621(Flag Air Carriers)


Ceiling Will Be... Far 121.621

• At least 1500 ft above lowest circling minimum descent altitude (MDA) if circling approach is required

• at least 1500 ft above the lowest ILS approach minimum OR 2000 ft above airport elevation which ever is greater

• visibility at airport will be at least 3 miles OR 2 miles more than the lowest visibility minimums for ILS

Flag Air Carriers


When Do You Need an Alternate?

If no alternate is available, relief is in “island reserves” (FAR 121.645)


Please don’t get lost!

S, Page 1

FLIGHTOPERATIONS

ENGINEERING


Stall Speed, Stall Warning,& Limitations on Maneuvering

Flight

S, Page 2For Training Purposes Only Copyright © 2009 Boeing. All rights reserved

Stall Speed Definition

• What is stall?

• Why is stall speed important?


Load Factor, n

Lift is the airplane total lift, wing body, empennage

WLn

WeightLiftn

=

=


Lift Equation

If lift is constant and velocity decreases then CL must go up

nW SqCL L==

369.295VnW

qSnWC 2

eL ==

SqSL=

= SCL 369.295V 2

e

Question, how do we increase CL ?Answer, increase angle of attack, α.


Lift versus Angle of Attack

Angle of Attack (AOA)

Lift

Coe

ffic

ient

0 +-

+

CL Max Lift @ αMax Lift


Aerodynamic Stall Speed

• Minimum speed that the wing can create enough lift to support the aircraft

• Maximum coefficient of lift that the wing can create

• ,gMax LL CC

1


High Lift Device (Flaps and Slats)

Takeoff

Landing

Cruise – Flaps Up


Effect of Flap on Lift Curves

CL

α

Flaps up

Takeoff Flaps

Landing Flaps

constantα

constantCL


Anatomy of a Stall

• Idle thrust, wings level, 1-g deceleration

• As airplane slows down– 1-g, Lift = Weight– Decrease in velocity– Increase in angle of attack (α) and therefore CL

• Eventually α and therefore CL reach the maximum that the wing can produce

• Flow separates, lift decreases, n decreases


Minimum Velocity

Maximum Liftg-break

Level flight deceleration

Idle thrust

Increasing angle of attack (AOA, α)

RecoveryVelocity keas

LiftWeight

1.0Load Factor,

n

qSnWCL =

Time



Definition – FAR Stall

• FAR Stall– Prior to the mid-80’s the pilot would continue to pull

aft stick to fly deep into the stall– Minimum speed during the stall maneuver was

declared stall speed– calculation ignores load factor, n when

calculating CL or speed

S369.295

VWC 2mine

sFARL =

SFARCL


Minimum Velocity


Idle thrust

Increasing angle of attack (AOA, α)

“Real” CLincluding n

Minimum Velocity

Velocity keas

LiftWeight

1.0Load Factor,

n

qSnWCL =

Load Factor ignoredin calculation of CLfor FAR Stall condition


Definition – 1-G Stall

• 1-g Stall– Since mid-80’s recovery is initiated shortly after the

“g-break”– Maximum lift point determines stall speed– calculation does take into account n, load factor

s369.295

VnWC 2

Lmaxeg1sL =

−

g1sLC −


Minimum Velocity


Idle thrust

Increasing angle of attack (AOA, α)Velocity

keas

LiftWeight

1.0Load Factor,

n

qSnWCL =

Maximum Liftg-break


Stall Speed Definitions

• Typically the FAR stall speed is 6-8% lower than 1-g stall speed

• To account for this difference, operational speeds based on 1-g stall speed use a lower factor than airplanes based on the FAR stall speed– V2 min = 1.2 VS FAR or 1.13 Vs 1-g

– VRef min = 1.3 VS FAR or 1.23 Vs 1-g

(continued)


Far 25.103 Stalling Speed (Excerpted From FAR's)

(a) VS is the calibrated stalling speed, or the minimum steady flight speed, in knots, at which the airplane is controllable, with:(1) Zero thrust at the stalling speed, or, if the resultant

thrust has no appreciable effect on the stalling speed, with engines idling and throttles closed;

(2) Propeller pitch controls (if applicable)…... (3) The weight used when VS is being used as a factor

to determine compliance with a required performance standard; (account for weight effects)and

(4) The most unfavorable center of gravity allowable.

Old FAR Stall speed definition pre-Amendment 25-108


Far 25.103 Stall Speed (Excerpted From FAR's)Current as of Jan. 2005

§ 25.103 Stall speed. [ 1-g rule]

(a) The reference stall speed, VSR, is a calibrated airspeed defined by the applicant. VSR may not be less than a 1-g stall speed. VSR is expressed as:

where:

VCLMAX = Calibrated airspeed obtained when the load factor-corrected lift coefficient

is first a maximum during the maneuver prescribed in paragraph (c) of this section. In addition, when the maneuver is limited by a device that abruptly pushes the nose down at a selected angle of attack (e.g., a stick pusher), VCLMAX may not be less than the speed existing at the instant the device operates;



(b) VCLMAX is determined with:

(1) Engines idling, or, if that resultant thrust causes an appreciable decrease in stall speed, not more than zero thrust at the stall speed;

(2) Propeller pitch controls (if applicable) in the takeoff position;

(3) The airplane in other respects (such as flaps and landing gear)in the condition existing in the test or performance standard inwhich VSR is being used;

(4) The weight used when VSR is being used as a factor to determine compliance with a required performance standard;

(5) The center of gravity position that results in the highest value of reference stall speed; and

(6) The airplane trimmed for straight flight at a speed selected by the applicant, but not less than 1.13VSR and not greater than 1.3VSR.



(c) Starting from the stabilized trim condition, apply the longitudinal control to decelerate the airplane so that the speed reduction does not exceed one knot per second.

(d) In addition to the requirements of paragraph (a) of this section, when a device that abruptly pushes the nose down at a selected angle of attack (e.g., a stick pusher) is installed, the reference stall speed, VSR, may not be less than 2 knots or 2 percent, whichever is greater, above the speed at which the device operates.

(d) rephrased - VSR must be 2 knots or 2 % above pitch/alpha/speed limiting system.


FAR 25.103 (a) (1) - Thrust Effect

• Zero thrust

ThrustIdle Level flight thrust required

CLS

ΔCLS due to thrust, typically small enough to ignore and use idle thrust

Flap xx


FAR 25.103 (a) (3) - Weight Effect

• Weight effect

Low weight High weight

ΔCLS due to aeroelasticity of the wing, as weight increases, CLS decreases

Flap xx

CLS

Gross Weight

Higher CL - Lower stall speed


FAR 25.103 (a) (4) - CG Effect

V

Lwing fwd cg

Wfwd cgLtail(neg) fwd cg

Ltotal = W = Lwing @ α1+ Ltail(neg) fwd cg

α1 = angle of attack required to create Lwing necessary to balance the airplane weight and down force due to the tail trim

Consider an airplane flying in trim at a chosen angle of attack, α1 and at the forward c. g.

Lwing @ α1= W – L tail(neg) fwd cg



• If c. g. is further aft, moment arm between center of lift on the wing and c. g. is reduced.

• This reduces the nose down moment due to the wing c. g. combination.

• Less down force is required from tail to trim airplane.

V

Lwing

Wfwd cg

Ltail(neg) fwd cgWaft cg

Consider airplane at same angle of attack, α1, but at aft c. g.

Reduced moment armmeans reduced nose down moment due to the wing lift

Less down force to balance moment

Ltail(neg) aft cg


> α2 therefore > Lwing aft @ α2

and > Daft @ α2

α1 Lwing fwd @ α1


V

Lwing fwd

Wfwd cg

Ltail(neg) fwd cg

> Lwing aft cg

Waft cg =

Ltail(neg) aft cg

is less negative than

Ltotal = W =

Ltotal = W = Lwing aft @ α2+ Ltail(neg) aft cg less negative

than at fwd c. g.

Lwing fwd @ α1+ Ltail(neg) fwd cg

Dfwd @ α1



• If weight is the same but the down force from the tail is less, the Lwing required to balance forces will be less.

V

Lwing

Wfwd cg

Ltail(neg) fwd cg

> Lwing aft cg

Waft cg =

Ltail(neg) aft cg

is less negative than

Lwing fwd @ α1= W – L tail(neg) fwd cg Lwing fwd @ α1

Reduce angle of attack to α2 to obtain required Lwing to balance forcesLwing aft @ α2

= W – L tail(neg) aft cg

and > W – L tail(neg) aft cg


α


Aft CG

Forward CG

Same airplane CL for same weight but less α required to create the CL.

Wing will stall at same α but higher Ltotal for equivalent conditons

(continued)

Airplane CL



Effect of C. G. on Stall CL

Gross WeightLow weight High weight

CLS

ConstantFwd C. G.

Many times at higher weight the fwd c. g. limit moves aft, manufacturers typically take advantage of this in determining stall CL

C.G.

High

Low

Forward limitFwd

Aft



FAR 25.103 (b) (1) - Entry rate

• Trim airplane at 1.2 VSFAR or 1.13 VS 1-g

• Decelerate into stall at 1 knot per second

CL S

Entry Rate - Kts/Sec-0.5 -1.0 -1.5

Given FlapTest C.G.

FAR Stall

1-g Stall

How the airplane is flown


FAR Stall or 1-g Stall Certification Basis

• Prior to mid-80’s all Boeing 7 series airplanes used the FAR stall speed method.

• During 767-300 certification issues came up on stall identification. These issues resulted in the 1-g certification method being used.

• FAR stall airplanes – 707’s, 727’s, 737-1/2/Adv/300, 747-1/2/300, 757-200,

767-200, DC-8, DC-9, DC-10

• 1-g stall airplanes – 737-4/.../900, 747-400, 757-300, 767-3/400, 777, 717,

MD-11, MD-80 (deep stall issues)


Stall Identification - Excerpted From FAR 25.201(d)

(d) The airplane is considered stalled when the behavior of the airplane gives the pilot a clear and distinctive indication of an acceptable nature that the airplane is stalled. Acceptable indications of a stall, occurring either individually or in combination, are—

(1) A nose-down pitch that cannot be readily arrested;

(2) Buffeting, of a magnitude and severity that is a strong and effective deterrent to further speed reduction; or

(3) The pitch control reaches the aft stop and no further increase in pitch attitude occurs when the control is held full aft for a short time before recovery is initiated.


Stall Characteristics - Excerpted From FAR 25.203Handling Qualities

(a) It must be possible to produce and to correct roll and yaw by unreversed use of the aileron and rudder controls, up to the time the airplane is stalled. No abnormal nose-up pitching may occur. The longitudinal control force must be positive up to and throughout the stall. In addition, it must be possible to promptly prevent stalling and to recover from a stall by normal use of the controls.

(b) For level wing stalls, the roll occurring between the stall and the completion of the recovery may not exceed approximately 20 degrees.


Stall Characteristics - Excerpted From FAR 25.203Handling Qualities

(c) For turning flight stalls, the action of the airplane after the stall may not be so violent or extreme as to make it difficult, with normal piloting skill, to effect a prompt recovery and to regain control of the airplane. The maximum bank angle that occurs during the recovery may not exceed—

(1) Approximately 60 degrees in the original direction of the turn, or 30 degrees in the opposite direction, for deceleration rates up to1 knot per second; and

(2) Approximately 90 degrees in the original direction of the turn, or 60 degrees in the opposite direction, for deceleration rates in excess of 1 knot per second.


Altitude Effect on Stall CL

• Lower altitude - higher stall CL MAX

• Older airplanes - Stall speeds at high altitudes (9-14,000 feet) and used at lower altitudes– Conservative for use at lower altitudes

• Newer airplanes - 737-500 and MD-11 on– Stalls flown at various altitudes– “Typical” trade - 2 to 3 knots per 10,000 feet– Data based on 1500 feet above airport pressure altitude


Altitude Effect on Stall CL

• Basic mechanism is a mach effect

• Higher altitude - higher mach no.

• Higher mach no.- earlier separation of flow from the wing

• Earlier separation of flow from the wing - lower CLS

• Lower CLS - higher stall speeds

Low weight High weight

CLS

High

Low

Sea Level

8000 feet


Speed Factors

• Operational speeds which are based on 1-g stalls use a lower factor for airplanes certified to the 1-g stall basis.

– V2 min = 1.2 Vs FAR or 1.13 Vs 1-g

– VRef min = 1.3 Vs FAR or 1.23 Vs 1-g

Note this says V2 min and VRef min , actual V2 and VRef may be selected for other reasons.


Workbook Problem

Do problem 1 in performance workbook.

• Compute speed margin to 1-g stall speed at V2 and VRef.


VS 1GV2/VS 1G

V2 Flap 20

VS 1GV2/VS 1G

V2 Flap 10

1361.19

1621391.23

171777-300ER270,000 kg

1381.25

1731431.30

184777-300270,000 kg

1521.13

1711571.13

177747-400350,000 kg

1391.15

1601431.17

167777-200ER270,000 kg

1211.24

1501301.21

157737-90070,000 kg

1211.21

1461291.17

151737-80070,000 kg

1201.13

1361291.13

146737-70070,000 kg

1271.15

1461371.13

155737-40060,000 kg

VS 1GV2/VS 1G

V2 Flap15

VS 1GV2/VS 1G

V2 Flap 5

Model

Stall Margin Example


VS 1GV2/VS 1G

V2 Flap 20

VS 1GV2/VS 1G

V2 Flap 10

1361.19

1621391.23

171777-300ER270,000 kg

1381.25

1731431.30

184777-300270,000 kg

1521.13

1711571.13

177747-400350,000 kg

1391.15

1601431.17

167777-200ER270,000 kg

1211.24

1501301.21

157737-90070,000 kg

1211.21

1461291.17

151737-80070,000 kg

1201.13

1361291.13

146737-70070,000 kg

1271.15

1461371.13

155737-40060,000 kg

VS 1GV2/VS 1G

V2 Flap15

VS 1GV2/VS 1G

V2 Flap 5

Model



VS 1GV2/VS 1G

V2 Flap 20

VS 1GV2/VS 1G

V2 Flap 10

1361.19

1621391.23

171777-300ER270,000 kg

1381.25

1731431.30

184777-300270,000 kg

1521.13

1711571.13

177747-400350,000 kg

1391.15

1601431.17

167777-200ER270,000 kg

1211.24

1501301.21

157737-90070,000 kg

1211.21

1461291.17

151737-80070,000 kg

1201.13

1361291.13

146737-70070,000 kg

1271.15

1461371.13

155737-40060,000 kg

VS 1GV2/VS 1G

V2 Flap15

VS 1GV2/VS 1G

V2 Flap 5

Model



Effect of Load Factor

SC369.295nWV

S369.295

VnWC

g1sLLmaxe

2Lmaxe

g1sL

−

−

=

=


Effect of Load Factor

• Increase in load factor – Increases stall speed– Which therefore reduces the speed margin to stall– Constant speed, level flight bank turn will increase

load factor


Load Factor/Bank Angle Relationship

Lift

φ

φ

Weight

Weight = Cos φ * Lift

The airplane must increase α to maintain altitude in a constant speed turn


Load Factor/Bank Angle Relationship

Weight = Cos φ * Lift

Load Factor, n = =LiftWeight Cos φ

1

or

Bank Angle = φ = Cos-1 1n


Workbook Problem


• Compute load factor and bank angle margin to 1-g stall speed assuming a constant speed, constant altitude turn.


Earlier Stall Speed Margin Example

VS 1GV2/VS 1G

V2 Flap 20

VS 1GV2/VS 1G

V2 Flap 10

13619 %

16213923 %

171777-300ER270,000 kg

13825 %

17314330 %

184777-300270,000 kg

15213 %

17115713 %

177747-400350,000 kg

13915%

16014317 %

167777-200ER270,000 kg

12124%

15013021 %

157737-90070,000 kg

12121 %

14612917 %

151737-80070,000 kg

12013 %

13612913 %

146737-70070,000 kg

12715%

14613713 %

155737-40060,000 kg

VS 1GV2/VS 1G %

V2 Flap15

VS 1GV2/VS 1G %

V2 Flap 5

Model


Load Factor/Bank

Margin

VS 1GV2/VS 1G

V2 Flap 20

Load Factor/Bank

Margin

VS 1GV2/VS 1G

V2 Flap 10

1.4245

13619 %

1621.5148

13923 %

171777-300ER270,000 kg

1.5650

13825 %

1731.6953

14330 %

184777-300270,000 kg

1.2838

15213 %

1711.2838

15713 %

177747-400350,000 kg

1.3240

13915%

1601.3743

14317 %

167777-200ER270,000 kg

1.5449

12124%

1501.4647

13021 %

157737-90070,000 kg

1.4647

12121 %

1461.3743

12917 %

151737-80070,000 kg

1.2838

12013 %

1361.2838

12913 %

146737-70070,000 kg

12715%

1461.2838

13713 %

155737-40060,000 kg

Load Factor/Bank

Margin

VS 1GV2/VS 1G %

V2 Flap15

Load Factor/Bank

Margin

VS 1GV2/VS 1G %

V2 Flap 5

Model

Load Factor/Bank Margin to 1 G Stall Example


Load Factor/Bank

Margin

VS 1GV2/VS 1G

V2 Flap 20

Load Factor/Bank

Margin

VS 1GV2/VS 1G

V2 Flap 10

1.4245

13619 %

1621.5148

13923 %

171777-300ER270,000 kg

1.5650

13825 %

1731.6953

14330 %

184777-300270,000 kg

1.2838

15213 %

1711.2838

15713 %

177747-400350,000 kg

1.3240

13915%

1601.3743

14317 %

167777-200ER270,000 kg

1.5449

12124%

1501.4647

13021 %

157737-90070,000 kg

1.4647

12121 %

1461.3743

12917 %

151737-80070,000 kg

1.2838

12013 %

1361.2838

12913 %

146737-70070,000 kg

12715%

1461.2838

13713 %

155737-40060,000 kg

Load Factor/Bank

Margin

VS 1GV2/VS 1G %

V2 Flap15

Load Factor/Bank

Margin

VS 1GV2/VS 1G %

V2 Flap 5

Model



Load Factor/Bank

Margin

VS 1GV2/VS 1G

V2 Flap 20

Load Factor/Bank

Margin

VS 1GV2/VS 1G

V2 Flap 10

1.4245

13619 %

1621.5148

13923 %

171777-300ER270,000 kg

1.5650

13825 %

1731.6953

14330 %

184777-300270,000 kg

1.2838

15213 %

1711.2838

15713 %

177747-400350,000 kg

1.3240

13915%

1601.3743

14317 %

167777-200ER270,000 kg

1.5449

12124%

1501.4647

13021 %

157737-90070,000 kg

1.4647

12121 %

1461.3743

12917 %

151737-80070,000 kg

1.2838

12013 %

1361.2838

12913 %

146737-70070,000 kg

12715%

1461.2838

13713 %

155737-40060,000 kg

Load Factor/Bank

Margin

VS 1GV2/VS 1G %

V2 Flap15

Load Factor/Bank

Margin

VS 1GV2/VS 1G %

V2 Flap 5

Model



Workbook Problem


• Compute speed margin to 1-g stall speed assuming a constant speed, constant altitude, 30 degree bank turn.


Speed Margin to 1-G Stall Speed to 30 Degree

• Q. What is the speed margin to 1-g stall for an airplane flying at 30 degree bank at the minimum speed margin for V2 selection (1.13 Vs 1g)?

• A. At 30 degree bank the stall speed has been increased by 7.5%.– Therefore the speed margin at this

condition is 5%

Note: for the 777-300 where the V2speed can be as high as 1.3Vs 1g , the speed margin would be 20% or more at a 30 degree bank


Conservatism's in Regulatory Stall Speed

• Thrust - in an emergency, the airplane will not be at idle/zero thrust.

• Center of gravity. In operation, the airplane’s operational c.g. will not be at the forward limit.

• Older airplanes also had conservatism because no credit was taken for the altitude effect.


Stall Warning

Stall Warning


FAR 25.207 Stall Warning (excerpted from FAR’s)

(a) Stall warning with sufficient margin to prevent inadvertent stalling with the flaps and landing gear in any normal position must be clear and distinctive to the pilot in straight and turning flight.

(b) The warning may be furnished either through the inherent aerodynamic qualities of the airplane or by a device that will give clearly distinguishable indications under expected conditions of flight. However, a visual stall warning device that requires the attention of the crew within the cockpit is not acceptable by itself. If a warning device is used, it must provide a warning in each of the airplane configurations prescribed in paragraph (a) of this section at the speed prescribed in paragraph (c) and (d) of this section.


FAR 25.207 Stall Warning

(c) When the speed is reduced at rates not exceeding one knot per second, stall warning must begin, in each normal configuration, at a speed, VSW, exceeding the speed at which the stall is identified in accordance with §25.201(d) by not less than five knots or five percent CAS, whichever is greater. Once initiated, stall warning must continue until the angle of attack is reduced to approximately that at which stall warning began.

(d) In addition to the requirement of paragraph (c) of this section, when the speed is reduced at rates not exceeding one knot per second, in straight flight with engines idling and at the center-of-gravity position specified in §25.103(b)(5), VSW, in each normal configuration, must exceed VSR by not less than three knots or three percent CAS, whichever is greater.

(continued)


FAR 25.207 Stall Warning

(e) The stall warning margin must be sufficient to allow the pilot to prevent stalling (as defined in §25.201(d)) when recovery is initiated not less than one second after the onset of stall warning in slow-down turns with at least 1.5g load factor normal to the flight path and airspeed deceleration rates of at least 2 knots per second, with the flaps and landing gear in any normal position, with the airplane trimmed for straight flight at a speed of 1.3 VSR, and with the power or thrust necessary to maintain level flight at 1.3 VSR.

(f) Stall warning must also be provided in each abnormal configuration of the high lift devices that is likely to be usedin flight following system failures (including all configurations covered by Airplane Flight Manual procedures).

(continued)


Stall Warning

• Natural stall warning - Buffet– The shaking of the airplane due to the air separating

from the wing as the wing stalls– Initial buffet is defined as 0.1 g peak to peak measured

at the pilot’s seat track

• Artificial stall warning - Stick Shaker– Mechanical system added to the airplane to warn the

pilot that stall is approaching– Typically a shaking of the yoke is accompanied by an

aural warning


Summary of FAR Stall Versus 1-G Stall Margins at V2 Min

FAR StallSpeed

1G StallSpeed

Approx.7 %

1.13 VS1G1.2 VSFAR V2 MinApprox.

the same


Summary of FAR Stall Versus 1-G Stall Margins at V2 Min

Stall Warning

Req.

7 %

3 - 5 %

Stall Warning

Req.

}

{

V2 MinApprox.

the same

1.13 VS1G1.2 VSFAR

FAR StallSpeed

1G StallSpeed

Approx.7 %


Workbook Problem


• Compute the speed margin to stick shaker speed and the speed margin from stick shaker speed to 1-g stall speed for following conditions.


Stick Shaker Margin Example

Vss/VS 1G Flap 10

Load Factor/Bank Margin SS

VSSV2/VSS %

VS 1GV2/VS 1G %

V2 Flap 10

1.031.4446

14320 %

13923 %

171777-300ER

1.031.5950

14626 %

14330 %

184777-300

1.051.1429

1657 %

15713 %

177747-400

1.031.3040

14714 %

14317 %

167777-200ER

1.061.3040

13814 %

13021 %

157737-900

1.071.1933

1389 %

12917 %

151737-800

1.061.1429

1377 %

12913 %

146737-700

1.031.2134

14110 %

13713 %

155737-400

Vss/VS 1G Flap 5


VSSV2/VSS %

VS 1GV2/VS 1G %

V2 Flap 5

Model



Vss/VS 1G Flap 10


VSSV2/VSS %

VS 1GV2/VS 1G %

V2 Flap 10

1.031.4446

14320 %

13923 %

171777-300ER

1.031.5950

14626 %

14330 %

184777-300

1.051.1429

1657 %

15713 %

177747-400

1.031.3040

14714 %

14317 %

167777-200ER

1.061.3040

13814 %

13021 %

157737-900

1.071.1933

1389 %

12917 %

151737-800

1.061.1429

1377 %

12913 %

146737-700

1.031.2134

14110 %

13713 %

155737-400

Vss/VS 1G Flap 5


VSSV2/VSS %

VS 1GV2/VS 1G %

V2 Flap 5

Model



Vss/VS 1G Flap 10


VSSV2/VSS %

VS 1GV2/VS 1G %

V2 Flap 10

1.033 %

1.4446

14320 %

13923 %

171777-300ER

1.033 %

1.5950

14626 %

14330 %

184777-300

1.055%

1.1429

1657 %

15713 %

177747-400

1.033 %

1.3040

14714 %

14317 %

167777-200ER

1.066%

1.3040

13814 %

13021 %

157737-900

1.077 %

1.1933

1389 %

12917 %

151737-800

1.066 %

1.1429

1377 %

12913 %

146737-700

1.033 %

1.2134

14110 %

13713 %

155737-400

Vss/VS 1G Flap 5


VSSV2/VSS %

VS 1GV2/VS 1G %

V2 Flap 5

Model


Buffet Limitations

• Buffet doesn’t just occur at low speed (stall warning)

• Buffet can occur at high speed also– Airflow separates from the wing because part of the flow

is supersonic– The deceleration of the air from supersonic to subsonic

causes a shock wave which causes buffet


Buffet Limitations

• At a given altitude the airplane has a range of speeds it can fly buffet free.

Speed HighLow


Buffet Limitations

• At a given speed the airplane has a maximum altitude it can fly buffet free

Highest buffet free altitude


Buffet Limitations

• At a given speed and altitude an airplane at wings level – no buffet

No BuffetAt maximum buffet free bank angle.

Buffet


Buffet Limitations

• Consider -

– Therefore the condition for buffet onset is defined by– n - load factor– W - weight– δ - pressure ratio i.e. pressure altitude– Mach no.

SM4.1481/nWC 2L

δ=


Buffet Limitations• Buffet - .1g

peak to peak

• Defined by a CL -Mach no. boundary

Buffet BoundaryFlaps up

0

0.2

0.4

0.6

0.8

1

1.2

1.4

0.2 0.25 0.3 0.35 0.4 0.45 0.5 0.55 0.6 0.65 0.7 0.75 0.8 0.85 0.9

Mach no.

Lift

Coe

ffici

ent

No Buffet

Buffet


Buffet Boundary

Lines of

A given W/δrepresentsa weight at an altitude.

Following the W/δ line shows the buffet free speed range.

nWδ


0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

0.2 0.25 0.3 0.35 0.4 0.45 0.5 0.55 0.6 0.65 0.7 0.75 0.8 0.85 0.9

Mach no.

Lift

Coe

ffici

ent

70,000 kg @ 37000 feet 1g flightnW/delta = .722*10^6


Buffet Limitations

• Specific altitude FL370– speed range


0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

0.2 0.25 0.3 0.35 0.4 0.45 0.5 0.55 0.6 0.65 0.7 0.75 0.8 0.85 0.9

Mach no.

Lift

Coe

ffici

ent

70,000 kg @ 37000 feet 1g flightnW/delta = .722*10^6

Low speed buffetM = 0.616

High speed buffetM = 0.865


Workbook Problem

Do problem 5 in the performance workbook.– Determine maximum altitude due to initial buffet at the

cruise mach of 0.8 and weight of 70,000 kg for 1-g flight.

Do problem 6 in the performance workbook. – Determine buffet free load factor and bank angle at the

cruise mach of 0.8, 35000 ft and weight of 70,000 kg.


Buffet Limitations

• Specific speed – 0.8M– Buffet free

bank angle margin

Or– @1g –

altitude range


0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

0.2 0.25 0.3 0.35 0.4 0.45 0.5 0.55 0.6 0.65 0.7 0.75 0.8 0.85 0.9

Mach no.

Lift

Coe

ffici

ent

70,000 kg @ 37000 fee t 1g flightnW/de lta = .722*10^6

@ 0.8 mach, FL370n = 1.332 - 41o bank angle margin

@ 0.8 mach, n=1M aximum buffe t free altitude ~ 42,600 fee t


Flap - Speed Schedule Maneuvering Speeds

• Maneuvering speeds are selected such that the airplane has at least a 40 degree bank capability when recommended procedures are followed for flap retraction

• This 40 degree bank capability represents a 25 degree bank turn plus 15 degree overshoot margin


Sample

1.0

1.2

1.4

1.6

1.8

2.0

Load Factor - g’s

0 20 40 60 80 100Speed Increment From VRef

40 Degree Bank

45 Degree Bank

15 Degree Bank

30 Degree Bank

Flaps

20, g

ear u

p

Flaps

5, ge

ar up

Flaps

1, ge

ar up

Flaps

up, g

ear u

p

V2

Maneuver Margins - Takeoff Flap Retraction


4. True or False, the stall speed for an airplane is the minimum speed the wing can create enough lift to support the weight of the airplane.

5. True or False, the stall speed for an airplane is the speed when the air flow begins to separate over the wing.

True, this is essentially the definition of “1g”stall speed.

False, Air flow separation will occur before the maximum lift or angle of attack actually occurs.


6. True or False, the stall speed is the minimum steady flight speed demonstrated during the stall maneuver during flight test.

7. True or False, a banked turn performed at a constant speed (V2) and in level flight or nearly level flight, requires the pilot to reduce the angle of attack.

True, This is essentially the definition of the “FAR”stall speed which was used in FAR performance calculations prior to the mid-80’s.

False, the lift force perpendicular to the direction of flight is what generates the turning force. If the airplane does not sink, the vertical component of lift must still equal or exceed the weight. Therefore lift must be increased above the “wings level” lift required. This is done by increasing the angle of attack.


8. How many ways can a pilot get into initial buffet?

Four. He or she can:• speed up into it...• slow down into it...• climb into it, and...• maneuver into it (e.g. bank)


9. True or False, the regulations require a jet transport always have the capability to bank up to an angle of 40 degrees without encountering buffet, stick shaker, or stall...

Jump to Structural

False, there isn’t a definitive requirement for the amount of maneuver capability required in all phases of flight. Requirements vary based on certification date, phase of flight, and certification agency.

FLIGHTOPERATIONS

ENGINEERING

1For Training Purposes Only Copyright © 2009 Boeing. All rights reserved

Airplane Noise

Mark MonsrudFlight Operations Engineering

Performance Engineer Operations CourseBoeing Commercial Airplanes

September 2009

1


Airplane Noise Course - Agenda

• Aircraft noise regulations

• Airplane noise certification

• Low noise takeoff and approach procedures

• Noise customer support


Community Airplane Noise

• Jet aircraft age in the 1950’s and increased operations in 1960’s• Growth of residential population near airports

– Complaints about jet noise and organized community resistance– Legal action against airports, airlines– Political pressure for regulation of operations

• Adoption of noise certification standards (FAR Part 36, 1969)• International standards for aircraft noise (ICAO Annex 16, 1971)• Airport noise regulations (1970 and on)

The Events Leading to Noise Certification


Airplane Noise Regulation Timeline

1970 1975 1980 1985 1990 1995 2000 2005

FAA FAR Part 36

Standards

ICAO Annex 16 Standards

New Designs

Production

Operation

New Designs

Production

Operation

Stage 2

Stage 1

Stage 1

No req’mt

No requirement

No requirement

Stage 1

Stage 3 Stage 4

Stage 2

Stage 3Stage 2

Stg 2Phase

Out

Chapter 2

Chapter 3 Ch. 4

Chapter 2Chapter 3Chapter

2Chapter 2Phase Out

Ch. 3-5 dB

RestrictionsIn EU


Growth in World Airport Noise Restrictions

* Based on 600+ airports in Boeing database; reference http://www.boeing.com/commercial/noise

11

2

23

3

4

4

5

56

6


QC – Quota Count• QC is an abbreviation for Quota Count.

– It is a method for imposing curfews and restrictions on the number of flights in and out of an airport (seasonal and/or day/night)

– AFM certified EPNdB noise levels are commonly used to determine the QC number assigned to an airplane

– Some airports have published QC noise level restrictions and some have QC levels along with a “do not exceed dB level”

– Some well known airports with QC restrictions are Heathrow, Gatwick, and Stanstead, England

• QC bands are in 3 dB increments for the system used in England – QC0 (Exempt) is < 84 EPNdB– QC0.25 is 84-86.9 range – QC0.5 is 87-89.9– QC1 is 90-92.9– QC2 is 93-95.9 range and so on for increasing QC numbers…


QC – Quota Count• There is no worldwide standard QC document

– A QC number at a one airport may not have the same EPNdB noise level restriction as the same QC number at another airport.

– Individual airports and regional government authorities may publish their own QC levels

• Stage 3 or Stage 4 dB certification levels may not have fixed (permanent) correlation to specific QC levels– QC levels may be variable with the local political climate and specific

airfield policy– To determine the QC level for your airplane model, look at the individual

airport QC definitions and then use the AFM noise characteristics pages (EPNdB) to compute the QC number


AFM Noise Page


AFM Noise Page


QC – Quota Count Example Calculation

EPNdBEPNdBEPNdBApproachQCMLW

ForArrival

EPNdBEPNdBSidelineEPNdBTakeoffQCMTOW

reForDepartu

9.8699.959..@

:

45.892/]0.939.85[2/]..[.@

:

=−=−=

=+=+=

• Example QC for Heathrow England is calculated:– 737-700 CFM56-7B24, MTOW=154500 lbs, MLW=129200 lbs– From 737 AFM EPNdB = 85.9, 93.0, and 95.9 for Takeoff, Sideline, and

Approach respectively

, which is QC 0.5

, which is QC 0.25


Noise Certification Standards

• International Civil Aviation Organization (190 members)

• Standards for adoption by member states

• Annex 16

• Federal Aviation Administration• U.S. domestic standard • FAR Part 36

• 3-Point evaluation scheme- Takeoff- Sideline (During takeoff)- Approach

• Noise unit: effective perceived noise level (EPNL)

• Noise limits based on maximum takeoff weight

ICAO U.S.A.


Annex 16/FAR Part 36 Noise Certification Reference Points

• Constant Configuration during takeoff– Gear retraction permitted

• Microphone height = 1.2m above the ground

• Noisiest approach configuration– Max flap, gear down


ICAO Annex 16/FAR 36Noise Certification Limits

0

5

0

APPROACH SIDELINE TAKEOFF110

105

100

95

90

85

NO

ISE

LIM

ITS

(EPN

DB

)

110

105

100

95

90

NO

ISE

LIM

ITS

(EPN

DB

)

110

105

100

95

90

NO

ISE

LIM

ITS

(EPN

DB

)

Chapter2/Stage 2 Chapter2/Stage 2

Chapter3/Stage 3

Chapter3/Stage 3

Chapter2/Stage 2

Chapter3/Stage 3>3 engines

3 engines<3 engines

TAKEOFF GROSS WEIGHT(1000 LB)

50 100 200 2000500 1000TAKEOFF GROSS WEIGHT

(1000 LB)

50 100 200 2000500 1000TAKEOFF GROSS WEIGHT

(1000 LB)

50 100 200 2000500 1000


1.7

-0.7

-1.8

-2.5

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

2.0

Takeoff Sideline Approach

Noise Certification — Trade Provisions

91.5 EPNdB(+1.7 EPNdB)

95.0 EPNdB(-0.7 EPNdB)

97.7 EPNdB-1.8 (EPNdB)

FAR 36 Trade Example:737-200A/JT8D-9, 14500 lbs thrust, MTOW 121500 lbs, MLW 107000 lbs

• For Chapter 3 certification, noise level limits may be exceeded at one or two measuring points provided that:– The sum of the exceedances is not greater than 3 EPNdB*– No single exceedance is greater than 2 EPNdB*– Total exceedance is offset by margin under limit at remaining measuring points

• *For Chapter 2, these values were 4/3 EPNdB

Noise levels relative to noise limit at each location


Summary of Chapter 4


Status of Boeing Airplanes Versus Chapter 4

0

5

10

15

20

25

30

0 100 200 300 400 500 600 700 800 900MTOW, 1000 lb

Delta EPNdB

747-400

777

767757

717

737NG

Chapter 4

Quieter

sample data of commercial airplanes


Strategies for Developing Low-Noise Departure Procedures

Determine the optimal low-noise vertical takeoff profile

Establish SID routes that avoid airport residential communities

Alti

tude

(ft)

Distance from Brake Release (nm)

Vertical Flight Profile

A

B

C


Strategies for Developing Low-Noise Departure Procedures – Procedure SelectionConsiderations:• Community locations Runway usage• Multiple runways Preferential runways

FlexibleDescribed as "Close-In" & "Distant" procedures

Other Guidance:

AC 91-53A

FlexibleProcedures can be designed to benefit communities regardless of airport proximityICAO PANS OPS

NADP 2

Described as "Distant" procedureICAO-B

ICAO PANS OPS NADP 1

Specific / Localized

Reduce noise at a specific locationICAO-A Modified

Specific

Described as "Close-In" procedureICAO-A

Procedure DefinitionPurposeNoise Abatement

Procedure

.

.


Climb thrust

Reduced thrust

Constant

Increase

Max climb

Derate climb

Constant

Increase

Max Takeoff

Derate

IncreaseThrustVelocityThrustVelocityThrustVelocity

En-route Climb

Segment C

Reduced Climb

Segment B

Takeoff

Segment A

2,000 ft to 4,000 ft800 ft to 1,500 ftH2 Transition B –> CH1 Transition A –> B

Strategies for Developing Low-Noise Departure Procedures – Optimize Vertical Profile

Considerations:• Aircraft types• Multiple runways• Community locations

Alti

tude

(ft)



A

B

C

H1

H2

Examples of performance parameters to optimize for reduced operational departure noise


ICAO PANS-OPS NADP1 (abatement community close to airport)

Alti

tude

(ft)



At or above 800 feet (240 m) AAL initiate power reduction

At no more than 3000 feet (900 m) AAL accelerate to final climb speed, retract flaps

AAL – Above Aerodrome Elevation.

Takeoff thrust, hold V2 + (10 to 20 knots)

After power reduction must still maintain a positive rate of climb and no less than the engine inoperative gradient requirement

Climb at V2 + (10 to 20 knots)


Alti

tude

(ft)



ICAO PANS-OPS NADP2 (abatement community distant from airport)

At or above 800 feet (240 m) AALinitiate power reduction and retract flaps while accelerating to VZF; Orretract flaps and climb at VZF + (10 to 20 knots), reduce power after flap retraction.

At 3000 feet (900 m) AAL accelerate to final climb speed

Takeoff thrust, hold V2 + (10 to 20 knots)

AAL – Above Aerodrome Elevation.After power reduction must still maintain a positive rate of climb and no less than the engine inoperative gradient requirement


Strategies for Developing Low-Noise Departure Noise Abatement Procedures


Strategies for Developing Low-Noise Departure Procedures – Establish Low-Noise SID Routes


Strategies for Developing Low-Noise Departure Procedures – Establish Low-Noise SID Routes

4044042804Source MS Mappoint, (c) Microsoft, Inc.

GORLO 1Z

GORLO 3V

Approximate SID location


Quiet Procedures Can Reduce Aircraft Noise in Communities

Quiet procedures can provide immediate benefits

Benefits vary widely with aircraft and procedure

Proposed procedures depend on the locations of the sensitive areas


Louisville CDA – Initial DemonstrationsUnited Parcel Service, Boeing, MIT, FAA, Airport, NASA

Continuous Descent ArrivalNoise Contours

Community

Conventional ApproachNoise Contours

Community

• A proof-of-concept demonstration of the environmental benefits of Continuous Descent Arrival (CDA)

• Automated RNAV procedure starting at 11,000 feet and entirely within Louisville airspace

• CDA can lower noise/emissions and save fuel/time


Real-time simulations are used to evaluate operational feasibility

Fast-time simulations are used to determine potential environmental benefits

• Customized airplane performanceBoeing Climbout Program (BCOP)Community Noise DocumentPerformance Engineers Manual (PEM)

• FAA Integrated Noise Model (INM)• Noise Monitor Prediction Models• Terrain and Population Models

Quiet Procedure Development ResourcesTools and Methods

Procedure development requires coordinated efforts with performance specialists, pilots and operations.


Some of the Tools Available for Analyzing Noise Abatement Procedures

Boeing Climbout Program (BCOP)

Community Noise Document(All Engine Document)

FAA Integrated Noise Module (INM)


Boeing Climbout Program (BCOP)

• Boeing has developed an application specifically designed to analyze and develop terminal area procedures.

• The Boeing Climbout Program (BCOP) is a Windows-based Graphical User Interface (GUI) application.

• The BCOP application will analyze the performance of SIDs, STARS, go-around and engine-out procedures.

• For a unique airframe/engine combination and user specified aircraft configuration, BCOP uses specific airport characteristics and user specified vertical and lateral profiles to produce three dimensional flight path information.

• A subset of the 70 BCOP output parameters available includes latitude, longitude, altitude, speed, climb gradient, rate of climb, time, fuel, ground track distance, and aircraft heading.


Noise Abatement Vertical Profile in BCOPSegment End Condition Flap Gear Thrust--------------- ------------------------- ---- ---- -----------1 Takeoff Gear Up. V2 + 20 N/A RET TKO2 Constant Speed 1500. ft Press Alt (MSL) N/A N/A TKO3 Constant Speed 3000. ft Press Alt (MSL) N/A N/A REQD(1.2%)4 Acceleration 250. IAS RET N/A MCLT5 Constant Speed 6000. ft Press Alt (MSL) N/A N/A MCLT


Example Horizontal Profile in BCOPSegment Type Segment End----------------- ------------------------------------------------------1 Fly 4º Heading Turn to Heading 316º at 5 DME AMS2 Fly 316º Heading Turn to Heading 272º at 7.1 DME AMS3 Fly 272º Heading Turn to Heading 213º at 11 DME SPY4 Fly 213º Heading Turn to intercept SPY Radial 243º with 15º bank angle5 Fly 243º Track from SPY Turn to intercept VOLLA Radial 239º with 5º bank angle6 Fly 239º Track from VOLLA End at X DME VOLLA


85 dBA Noise Footprint from BCOP-INM

Start of takeoff roll, noise approximates static engine data

Noise necks down due to thrust lapse with airplane speed

Noise balloons with reduced ground attenuation as airplane gains altitude

Thrust Cutback

Noise tapers as distance increases


Community Noise Document• Presents all engine operating takeoff and climb performance and

community noise characteristics for a specific Boeing airframe and engine combination (for example, 737-800/CFM56-7B24).

• Document may be used to check Standard Instrument Departure (SID) profiles with all engines operating and to determine centerline noise levels under the takeoff and approach flight paths of the airplane.

• Flight path is based on actual performance with all engines operating and is inappropriate for compliance with FAR Part 25 requirements.

• Airplane performance is based on aerodynamic characteristics and engine performance derived from FAA demonstration flight tests. Performance is shown for the full range of airplane certified takeoff temperature and altitude envelope.

• Data is included for takeoff thrust and climb thrust ratings.


Community Noise DocumentTakeoff Flight PathAll Engines Operating


Community Noise DocumentTakeoff Climb Profile Analysis Procedure


Noise Metrics in the Community Noise Document

Used for calculating noise levels under the flight path– Charts for flight profile (altitude, distance, velocity, thrust)– Noise level charts in several units:

• A-weighted sound pressure level (dBA)• Peak perceived noise level (PNdB)• Sound exposure level (SEL-dB)• Some older books have dBA, dBD, and EPNdB

– Data is relative to standard day reference conditions


Community Noise DocumentNoise Under the Takeoff Flight Path


Community Noise DocumentNoise Under the Approach Flight Path


FAA’s Integrated Noise Model (INM)

The INM model generates contours and other information for use in determining impact of aircraft noise around airports.

• Analyze aircraft noise and determine noise abatement procedures

• Develop noise mitigation programs

• Provide information for future land use planning and airport master plan


EGA

Airport information

FAA’s Integrated Noise Model (INM)

Performance data

Noise data INMCalculationRoutines

Noise Contours

Time Above a Noise Level

Noise at a Point


INM Calculation Grid Example

Noise values are computed for each location on a grid for the flight profile

Lateral Distance

Height

Ground Roll

Initial Climb

Accel & Flap Retract

Climb

Power and Speed Changes

Distance from start of takeoff

A curve of constant noise level (contour) can be plotted


INM Links on FAA Web Site

• Version 7 Information– http://www.faa.gov/about/office%5Forg/headquarters%

5Foffices/aep/models/inm%5Fmodel/

• Order Form– http://www.faa.gov/about/office%5Forg/headquart

ers%5Foffices/aep/models/inm%5Fmodel/inm7_0a/media/order70a.pdf


Boeing Community Noise Customer Support

• Community noise support extends over the life of the airplane– Pre-delivery and in-service

DeliveryTime

Airplane in serviceSales

Airplane Design

Certification

Certification governsPre-delivery activity

Airport noise compliance governs daily operation


Boeing Community Noise Customer SupportBegins with Advanced Technology

Chevrons on Quiet Engine Demonstrator

Improvements in Lining Technology

GE90-115B78% increase in effective lining area (160.4 ft^2)

Landing gear “Toboggan”

fairings

QTD – Quiet Technology Demonstrator



During development/sale of airplane:

• Recognition that different markets impose different requirements

• Brochures/sales charts form basis of customer decisions

• Customers prioritize critical markets– Drives the design (new airplane, or customer options

on existing)

• Community noise guarantees (FAR 36, airport noise)



In-service support after delivery:

• Address questions about airport rules– New markets often have different requirements– Airport noise rules change

• Assist customers in negotiations with airport authorities– Occasional demonstration test

• Calculation of noise impact in adjacent communities– Contours (during ground operation, takeoff, and landing)– Monitor levels



In-service support after delivery (continued):

• Provide guidance on flight procedures to minimize noise– Dependent on where noise-sensitive areas are located– Standards for noise abatement procedures (AC91-53A,

NADP 1 & 2)

• Special noise reduction programs– New markets may require additional noise reduction– Impact of some airplane features not fully understood until in-

service– May involve new features

• (Additional nacelle lining, changes in engine control schedules, etc)– Change to avionics to assist pilots flying noise abatement


Airplane Noise Course - Summary• Aircraft noise regulations

• Airplane noise certification

• Low noise takeoff and approach procedures

• Noise customer support

FLIGHTOPERATIONS

ENGINEERING

1For Training Purposes Only Copyright © 2009 Boeing All rights reserved

Dispatch Deviations

Brian J. BorthwickPerformance Engineer Operations Course

Boeing Commercial AirplanesSeptember 2009


Objectives

• Understand the concept

• Be aware of the development process

• Become acquainted with the supporting documents

• Consider the concept in practice

• Appreciate the benefits

Dispatch Deviations


Agenda• Introduction

- Dispatch Deviation – Definition / Purpose- Benefits of Deferred Maintenance- Authorization for MEL Dispatch

• MEL Development / Approval Process• Document Overview

- Master Minimum Equipment List (MMEL)- Dispatch Deviations Guide (DDG)- Airline's Minimum Equipment List (MEL)

• Performance Considerations

Dispatch Deviations


Dispatch Deviation – Definition / Purpose

What is a Dispatch Deviation?

• Approved revenue operation with inoperative or missing equipment



The Minimum Equipment List (MEL) is the authorizing document

• The MEL allows safe continued revenue operation with specific items of equipment inoperative (deferred maintenance)

(All items related to airworthiness and not included in the listare required to be operative)



Safety is maintained by:

• Appropriate operational limitations

• Transfer of the function to another operating component

• Reference to other instruments

• Limited repair interval



NOT intended to allow continued operation for an indefinite period of time with inoperative equipment

• Repair of deferred items should occur as soon as conditions permit


Dispatch Deviations

• Introduction- Dispatch Deviation – Definition / Purpose- Benefits of Deferred Maintenance- Authorization for MEL Dispatch





Benefits of Deferred Maintenance

• Offers Economic benefits due to optimization of:

– Maintenance staff

– Spares inventory

– Maintenance facilities

• Helps Operators Maintain Dispatch Schedule

– Minimizes mechanical delays

– Minimizes disruption

• Improves Customer Schedule Convenience

The ability to defer maintenance is essential for continuity of operation



Deferred Maintenance is vital to operations

• Scheduled ground-time is based on minimum delays

• Aggressive turnaround schedules preclude correcting discrepant items at the gate



MEL Dispatch is Performed Often

• Typical number of flight segments with deferred maintenance per the MEL:

Yearly average = 20 to 50%

Peak season = 50% or more

(Items accumulate during the day and are cleared during overnight or next maintenance)


Dispatch Deviations






Authorization for MEL Dispatch

MEL Legal Authorization

• FAR 121.628: Inoperable Instruments and Equipment

“No person may takeoff an airplane with inoperable instruments or equipment installed unless the following conditions are met:

(1) An approved Minimum Equipment List exists for that airplane.



The MEL and the Type Certificate

• Airplane Type Certificate is not compromised by the MEL (FAR 121.628)

– Adoption of a MEL item does not require re-certification of the design

– The MEL is considered to be an approved change to the type design



The MEL and the Airworthiness Release

• An airworthiness release is not compromised by the MEL (FAR 121.628)

• Mechanic is not in violation of the FAR’s when deferring maintenance under the MEL

– Airworthiness release states the work was done in accordance with the Operator’s manuals

– MEL is one of the Operator’s approved manuals


MEL Development / Approval Process

Purpose / Benefit / Authorization

Questions ?Questions ?


Dispatch Deviations






Document Relationship

Coordination

Airline MEL

Master MEL(MMEL)

FAA Controlled

Dispatch DeviationsGuide (DDG)Boeing Document

Company Procedures

Flight OpsMaintenance

CompanyPolicies

Standards

Configuration Deviation List

(CDL)AFM AppendixFAA Approved



Master MEL(MMEL)

FAA Controlled

Airline MEL


Company ProceduresFlight OpsMaintenance

CompanyPolicies

Standards



Process




Organizational Relationships

Manufacturer FAA

Certification

Operations

Airlines

Boeing Engineering

FAAEngineering

(ACO)

Boeing Flight Operations Engineering

(FLOE)

FAA AircraftEvaluation

Group (AEG)

Master Minimum Equipment List (MMEL)

(FAR Part – 121)

(FAR Part – 25)



• FAA Document

– Lists items of equipment which may be inoperative in revenue service

– Published for a given airplane type (e.g., 767 MMEL covers –200/300/400ER, GE/PW/RR)

• Operators create and use their own Minimum Equipment List (MEL) based on the MMEL




For example…

MMEL



How does an item get in the MMEL?

• The FAA Flight Operations Evaluation Board (FOEB) is responsible for the development and control of the Master MEL

• No set interval for the FOEB to meet

– Usually yearly for a new airplane type

– As required for more mature designs




FOEB members:

• Chairman - typically the FAA Part 121 pilot assigned to the airplane

• FAA Flight Test pilot most familiar with the airplane

• FAA Air Carrier Maintenance and Avionics Specialist assigned to the Maintenance Review Board for the airplane

• FAA Air Carrier Operations Specialist

• Any other personnel deemed necessary by the chairman (often including another chairman)




Submittal of proposals:

• U.S. Operators

– Submit candidate items to FAA through their Principal Operations Inspector (POI)

• Non-U.S. Operators

– Submit items through the airplane manufacturer




Approval process:

• FOEB meeting

– Evaluate proposed items

– Open to public

• FOEB Approval

• Final review by FAA Headquarters (Washington) to ensure adherence to FAA policy

• Entire revision process generally takes 6-8 months




• FAA publishes the MMEL

– Electronic Bulletin Board and Web (http://fsims.faa.gov)

• Distribution

– Manufacturer typically distributes at least one copy to each Operator (Available on MyBoeingFleet.com)

– U.S. Operators may also get a copy from their POI




• Other regulatory agencies may issue MMEL supplement which modifies the FAA MMEL:

– EASA (Europe)

– Transport Canada

– Aviation Register (CIS)

– Others




Fundamental Qualification Criterion:

• An “acceptable level of safety” must be maintained considering the next critical single failure or event

– Effect(s) on other systems/components and flight crew workload is considered

– This does not mean the same standards for FAR Part 25 certification need to be met

References:

• FAA Engineering Order 8900.1, Flight Standards Information Management System (FSIMS)

• MMEL Preamble




Assessment Criteria:

• Consequences of the Next Critical Failure (NCF) after dispatch with an inoperative system, component or function

– Probability of occurrence for NCF is considered = 1.

• Interrelationships of inoperative system functions during the dispatch period, accounting for overall operational effects including pilot workload

• Operational and engineering judgment of the consequences of dispatching the airplane with inoperative equipment is always considered and applied




General Criteria:

• More restrictive operating limitations may be required

• Airplane performance penalties may be required if performance is affected

• Transfer of function to another operating component may be required

• Additional or modified flight crew procedures may be required




Limiting Factors:

• Items will NOT be included in the MMEL if they:

– Obviously compromise airworthiness

– Obviously are not related to airworthiness

• The MMEL may not deviate from:

– AFM Limitations

– AFM Emergency Procedures

– Airworthiness Directives (ADs)










Master MEL(MMEL)

FAA Controlled

Airline MEL



CompanyPolicies

Standards

Process


• FAA approved Appendix to the Airplane Flight Manual (AFM)

• Allows operation with secondary airframe and engine parts missing

• Alternate certification - No repair interval

MEL Development / Approval ProcessConfiguration Deviation List (CDL)


Legal Authorization

• FAA approved under Part 25 (certification)

• Applicable to multiple configurations (minor models, different engine types)



Purpose:

• The CDL allows safe continued operation with specific items of equipment missing (deferred maintenance)

• Safety is maintained by:

– Appropriate operational limitations

– Performance penalties




Purpose (Cont’d):

• CDL items are typically airplane exterior components such as:– Non-structural Fairings

– Access Panels

– Small Doors

– Aerodynamic Seals

– Light Lenses

• CDL items typically affect airplane drag or stall speeds

Configuration Deviation List (CDL)



Submittal of proposals:

• No regular, defined process

• Operators submit items through the airplane manufacturer

• Revised on as-needed basis



Approval process:

• Boeing technical review

• FAA Aircraft Certification Office (ACO) approval

• AFM CDL Appendix revised

Configuration Deviation List (CDL)MEL Development / Approval Process



Part 25 Certification Criteria:

• Airplane structure, systems, flying qualities not compromised

• More restrictive operating limitations may be required

• Performance penalties for missing items:

– Takeoff limit weight

– Landing limit weight

– Enroute climb limit weight

– Possible cruise fuel burn adjustment (DDG)




• General Limitations– AFM Limitations are applicable

except as amended by the CDL

– Placards must list associated limitations for the pilot

– Unless specified, parts from different subsystems may be missing

– Penalties are cumulative

– A 100 lb penalty will be applied for each “negligible” penalty in excess of three



• General Limitations (Cont’d)










Master MEL(MMEL)

FAA Controlled

Airline MEL


CompanyPolicies

Standards

Process


• The DDG is a guidance document published by the airplane manufacturer

• The DDG is intended to assist airlines in developing procedures required to operate the aircraft in non-standard configurations allowed by the MMEL and the CDL

– A reference for development of the airline MEL

MEL Development / Approval ProcessDispatch Deviations Guide (DDG)


Provides:

• Suggested Operations (O) and Maintenance (M) procedures to meet MMEL requirements

• Can include suggested position and content of placards

• EICAS message list to assist in determination of possible MEL relief (except 737)

• Can include drawings and pictures to assist in the location and identification of MMEL/CDL items

MEL Development / Approval ProcessDispatch Deviations Guide (DDG)


Maintenance (M) and Operations (O) Procedures:

• Technically correct to the best of Boeing’s knowledge; not FAA approved

• Guidance information only; Operator must review for adequacy

Dispatch Deviations Guide (DDG)MEL Development / Approval Process


Maintenance (M) and Operations (O) Procedures (Cont’d):

• Not necessarily the only valid procedures;

– Operator may develop alternate procedures which better meet their unique needs (subject to local regulatory approval)

• If DDG information conflicts with the AFM, MMEL, or CDL, the FAA approved documents take precedence



• Boeing publishes the DDG

– Revision within 45 days after MMEL revision

• Distribution

– Immediately available on MyBoeingFleet.com

– Printed copies available upon request




Dispatch Deviations Guide (DDG)






Master MEL(MMEL)

FAA Controlled

Airline MEL


CompanyPolicies

Standards


Process


Airline Minimum Equipment List (MEL)

• FAA requires each Operator to develop their own MEL

– Fundamentally based on the MMEL (and DDG)

• The Master MEL is not intended for operational use

– MMEL (and DDG) is a generic, reference document

• Operator’s MEL frequently differs in format and content from the MMEL/DDG



• Customized for the airline’s specific configurations and operations:

– Remove references to equipment that is not in the Operator’s fleet (e.g., engine types)

– Specify equipment required by operating rules

• May be more restrictive than the FAA requirements

• May contain equipment, which for administrative control reasons, are best placed within the MEL section of the Operator’s manual

MEL Development / Approval ProcessAirline Minimum Equipment List (MEL)


FAA MASTER MEL

AIRLINE STANDARDSAND POLICIES

AIRLINE MEL(DRAFT)

MANUFACTURER’SRECOMMENDATIONS

(DDG)

GENERALPROCEDURES

FLIGHT OPERATIONSPROCEDURES

MAINTENANCEOPERATIONSPROCEDURES

ADMINISTRATIVE

CONTROL

PREPARATION

DISTRIBUTION

DOWNLINE NOTIFICATIONS

FLIGHT CREW

DISPATCH/FLIGHT FOLLOWING

PERFORMANCEPENALITIES

ENROUTE EFFECTS

DOWNLINE NOTIFICATIONS

SECURING ITEMS

PLACARDING

DEFERAL

TRACKING

CLEARING

FAA APPROVAL AIRLINE MEL

Airline MEL Development and Approval Process (Typical)

Coordination

© 1999, 2001 J. Hessburg



• Principal Operating Inspector (POI) or appropriate government agency will review the draft MEL for:

– Nothing less restrictive than MMEL

– Nothing contradicts AFM

– Nothing violates AD’s

– (O) and (M) procedures required by MMEL are adequate

– There is a defined management process for the use and control of the MEL

– Suitable training curriculum exists

– Suitable manual material for use exists

Airline Minimum Equipment List (MEL)MEL Development / Approval Process


At conclusion of review:

• POI approves/signs the Operator’s MEL

• Signs appropriate revision to the Operations Specification

Airline Minimum Equipment List (MEL)MEL Development / Approval Process




Airline Minimum Equipment List (MEL)


Dispatch Deviations






Document Overview

• Documentation• Usage



Document OverviewMMEL Definitions


4. Each inoperative item must be placarded to inform and remind the crewmembers and maintenance personnel of the equipment condition.NOTE: To the extent practical, placards should be located adjacent to the control or indicator for the item affected; however, unless otherwise specified, placard wording and location will be determined by the Operator.

MMEL Definitions

Document Overview


5. "-" symbol in Column 2 and/or Column 3 indicates a variable number (quantity) of the item installed.

.

.

.

9. "Flight Day" means a 24 hour period (from midnight to midnight) either Universal Coordinated Time (UCT) or local time,as established by the Operator, during which at least one flightis initiated for the affected aircraft.

MMEL Definitions

Document Overview


12. "Inoperative" means a system and/or component malfunction tothe extent that it does not accomplish its intended purpose and/or is not consistently functioning normally within its approved operating limit(s) or tolerance(s).

.

.

.

14. Inoperative components of an inoperative system: Inoperative items which are components of a system which is inoperative are usually considered components directly associated with and having no other function than to support that system. (Warning/Caution systems associated with the inoperative system must be operativeunless relief is specifically authorized per the MMEL).

MMEL Definitions

Document Overview


Document Overview

15. "(M)" symbol indicates a requirement for a specific maintenance procedure which must be accomplished prior to dispatch.

Normally these procedures are accomplished by maintenance personnel; however, other personnel may be qualified and authorized to perform certain functions. Procedures requiring specialized knowledge or skill, or requiring the use of tools or test equipment should be accomplished by maintenance personnel. The satisfactory accomplishment of all maintenance procedures, regardless of who performs them, is the responsibility of the Operator. Appropriate procedures are required to be published as part of the Operator’s manual or MEL.

MMEL Definitions


Document Overview

16. "(O)" symbol indicates a requirement for a specific operations procedure...

Normally… accomplished by the flight crew; however, other personnel may be qualified and authorized … The satisfactory accomplishment of all procedures… is the responsibility of the Operator. Appropriate procedures are required to be published as a part of the Operator’s manual or MEL.

NOTE: The (M) and (O) symbols are required in the Operator’s MEL unless otherwise authorized by the Administrator.

MMEL Definitions


Document Overview

Repairs should be made at the first opportunity -…additional malfunctions could ground the airplane

MMEL Definitions


23. Electronic fault alerting system – General

a. BOEING (B-757/767, B-747-400, B-777)

Boeing airplanes equipped with Engine Indicating and Crew Alerting Systems (EICAS), provide different priority levels of system messages (WARNING, CAUTION, ADVISORY, STATUS and MAINTENANCE). Any messages that affect airplane dispatch statuswill be displayed at a STATUS message level or higher. The absence of an EICAS STATUS or higher level (WARNING, CAUTION, ADVISORY) indicates that the system/component is operating within its approved operating limits or tolerances.

System conditions that result only in a maintenance level message, i.e. no correlation with a higher level EICAS message, do not affect dispatch and do not require action other than as addressed within an Operator’s standard maintenance program.

MMEL Definitions

Document Overview


25. "***" symbol in Column 1 indicates an item which is not required by regulation but which may have been installed on some models of aircraft covered by this MMEL.

.

.

.

27. "Day of Discovery" is the calendar day an equipment/instrument malfunction was recorded in the aircraft maintenance log and or record. This day is excluded from the calendar days or flight days specified in the MMEL for the repair of an inoperative item of equipment. This provision is applicable to all MMEL items, i.e., categories "A, B, C, and D."

MMEL Definitions

Document Overview


28. “Considered Inoperative”, as used in the provisos means that item must be treated for dispatch, taxi and flight purposes as though it were inoperative. The item shall not be used or operated until the original deferred item is repaired. Additional actions include: documenting the item on the dispatch release (if applicable), placarding, and complying with all remarks, exceptions, and related MMEL provisions, including any (M) and (O) procedures and observing the repair category.

MMEL Definitions

Document Overview


29. “Is not used” in the provisos, remarks or exceptions for an MMEL item may specify that another item relieved in the MMEL “is not used.” In such cases, crewmembers should not activate, actuate, or otherwise utilize that component or system under normal operations. It is not necessary for the Operators to accomplish the (M) procedures associated with the item. However, operational requirements must be complied with, and an additional placard must be affixed, to the extent practical, adjacent to the control or indicator for the item that is not used to inform crewmembers that a component or system is not to be used under normal operations.

MMEL Definitions

Document Overview


30. “Nonessential Equipment and Furnishings (NEF)” are those items installed on the aircraft as part of the original certification, supplemental type certificate, or engineering order that have no effect on the safe operation of flight and would not be required by the applicable certification rules or operationalrules. They are those items that if inoperative, damaged or missing have no effect on the aircraft’s ability to be operated safely under all operational conditions.

MMEL Definitions

Document Overview


MMEL Preamble

Document Overview

• The FAA MMEL is used as the basis for development of the Operator’s specific MEL

• The Operator’s MEL may differ in format but cannot be less restrictive than the FAA MMEL


MMEL Preamble (Cont’d)

Document Overview

• Operator’s MEL must provide suitable Placard, Operations and Maintenance procedures to maintain safety

• Repairs shall be made at earliest opportunity

• Operator is responsible for determining airplane condition is safe for operations

• Operator is responsible for exercising the necessary operational control: Go/No-Go


• Maintenance action

• Procedure change

• Other equipment required

• Other systems affected

MMEL Example

Document Overview


• Same as above, plus:Maintenance verification requirement

MMEL Example

• Crew verification requirement

• Flight restriction


Document Overview


• MMEL is not the sole source for all operational equipment requirements

• MMEL contains some explicit operational restrictions:– “Except for ER…”

– “…flight remains within 120 minutes of landing at a suitable airport”

• Many MMEL restrictions require further review for operational applicability:– “…approach minimums do not require its use”

– “…enroute operations do not require its use”

– “…other procedures do not require its use”

– “…required by FAR”

What about ETOPS, Cat I/II/III, RVSM, RNP, etc?

Document Overview


• Flight restrictions

• Performance penalties

• Minor model specific entries

• Operational limitation


MMEL Example

Document Overview


Document Overview

• Maintenance action –verification requirement

• Use of other equipment required

• Operational procedure

• Operational limitation

MMEL Example


Document Overview

• Operational implications:

– ETOPS

– Outstation facilities

– Other inoperative items

MMEL Example



Document Overview



Dispatch Deviations






• Documentation

• Usage


Document Overview


Document Overview

Organization

DDG


What is EICAS?

• The Engine Indicating and Crew Alerting System (EICAS) is the primary means of displaying airplane system information to the flight crew

• EICAS consolidates engine and subsystem indications and provides a centrally located crew alerting function

• EICAS displays System Alerts (Warning, Caution, and Advisory), Communication Alerts, Memo messages, and Status messages

DDG

Document Overview


EICAS Display

DDG

Document Overview


EICAS Message Cross Reference List:

• Provided as a “Quick Reference” between EICAS messages and Master Minimum Equipment List (MMEL) items which may provide dispatch relief

• Applicable to 757, 767, 747-400, and 777

DDG

Document Overview


Document Overview

• None: No MMEL item (relief) for the failure condition indicated by this message

EICAS Message Cross Reference List

• N/A: No MMEL item listed since message does not indicate a failure

DDG


Document Overview

DDG

EICAS Message Cross Reference List

• Message types


EICAS Messages

• Status messages indicate equipment faults which affect dispatch capability but are not necessarily identified by higher level EICAS messages

• Maintenance messages do not affect dispatch but must be corrected in accordance with the Operator’s approved maintenance program

• Normal crew procedures require checking status messages during cockpit preparation to determine airplane dispatchability

DDG

Document Overview


EICAS Messages (Cont’d)

• Boeing philosophy: After engine start it is not necessary to check status messages

– Operators may establish different policy for economic reasons

• Any message adversely affecting safe continuation of the flight or requiring crew attention, will appear as an EICAS alert message (WARNING, CAUTION, or ADVISORY)

DDG

Document Overview


EICAS Messages (Cont’d)

• What about a failure after engine start, butbefore takeoff ?

– After engine start and prior to takeoff, any alert message requires accomplishment of the appropriate non-normal procedure by the crew

– Upon completion of the non-normal procedure and prior to takeoff, the DDG or airline equivalent (company MEL) should be consulted to determine if dispatch relief is available

DDG

Document Overview


EICAS Message Cross Reference List:

• What do you do following display of a status message prior to engine start, or an alert message prior to takeoff ?– Determine if dispatch relief available

– No: Fix the problem

– Yes: Apply MEL procedures and dispatch the airplane

DDG

Document Overview


Document Overview

Section 2 - MEL

• Organized just like the MMEL

• Duplication of FAA Definitions and Preamble

• Items numbered same as MMEL

DDG


Document Overview

Section 2 - MMEL

• Top part is duplicate of MMEL

• Followed by suggested placards and (M) and (O) procedures as appropriate

DDG


Document Overview

Section 2 – MMEL

• Duplicate of MMEL

• Suggested (M) procedure (note engine-specific steps)

DDG


Document Overview

Section 2 - MMEL

• Suggested (O) procedure (note model-specific penalties)

• ETOPS planning information

• Advisory information for flight crew

DDG


Document Overview

Section 3 - CDL

• Organized similar to the CDL AFM Appendix

• Section contains a repeat of the AFM CDL limitations plus additional information on trip fuel adjustments for items

DDG


Document Overview

Section 3 - CDL

Fuel burn adjustment(Increase flight planning fuel by 0.25%/1000 lb enroute climb weight penalty)

DDG


Document Overview

Section 3 - CDL

• General Locations

DDG


Document Overview

Section 3 - CDL

• Duplicate of AFM CDL Appendix information

• Performance penalties if applicable

• Location illustration

• Illustration of item

DDG


Document Overview

Section 4 - Miscellaneous

DDG



Document Overview



Dispatch Deviations






• In development and application of your MEL, coordination is the key

Airline MEL

Document Overview


Deferral Process (Typical)

Coordination

LOGBOOK ENTRY FIX THE ITEM

CLEAR DEFERRED LOG

NOTIFY MAINTENACE NOTIFY DISPATCH NOTIFY PIC

DEFER?

MAINTENACE CONTROL STATIONMAINTENANCE

DISPATCH/FLIGHTFOLLOWING

NOTIFY MAINTENANCEPLANNING & RECORDS

TRANSFER ITEM TO DMI LOG &

RELEASE AIRPLANE

DISARM SYSTEM

START THE CLOCK

SCHEDULE WORK

PLACARD

ROUTE PENALTIES

PERFORMANCEPENALTIES

RELEASE FLIGHT

NO

NO

YES

YES

ITEM IN MEL?

© 1999, 2001 J. Hessburg

Airline MELDocument Overview


Dispatch Deviations






Performance Considerations

• Operations Impact

• Method of Performance Adjustments

• MEL Dispatch

Example: Inoperative AC Pack(s) – 777

• MEL Dispatch with Multiple Inoperative Items



The required operations procedures may include:

• Operations restrictions / limitations

• Airplane performance adjustments

Airline Operations



Airline Operations

MEL dispatch configuration may affect:

• Engine thrust – Decreased or Increased– Non-standard bleed air configuration or higher minimum idle

• Airplane drag - Increased– Delayed flap retraction, tail skid extended

Continued



MEL dispatch configuration may affect: (Cont’d)

• Fuel burn

– Increased from APU running, non-normal bleed configuration, etc.

• System operating times

– Alternate flap retraction, manual spoilers, etc.

• Braking characteristics

– Spoiler deployment, wheel brakes, thrust reversers, etc.

Airline Operations



Adjustments are determined by Aerodynamics Engineering analysis with emphasis on:

• Full range of the flight envelope

− Temperature, altitude, wind, etc.

• Flight configurations

− Flap setting, weight, etc.

• Airport characteristics

− Runway length, slope, obstacles, etc.

Method



Performance calculated using approved Airplane Flight Manual methods for the affected Flight segment:

• Takeoff field length

• Takeoff Climb

• Obstacle clearance profile

• Third segment distance

• Maximum level off height

• Enroute Climb

• Approach/Landing Climb

Method



Boeing performs parametric analysis to determine how airplane performance limited weight requirements are affected

Method



Performance adjustments are published in Boeing DDG as decrements to the performance limited weights

• Most conservative weight decrement is identified for affected flight phase

− Takeoff

− Enroute Climb

− Approach/Landing

Method



In some cases, Operators may calculate and use less conservative performance adjustments for their specific operation when using Boeing performance analysis software, such as the Onboard Performance Tool (OPT)

Method



Some adjustments require a more sophisticated model than is available in Boeing performance software and the Operator cannot improve on the DDG performance adjustment

• Bleed or fan-air extraction

• Drag increases

Method



MEL Dispatch with inoperative AC Pack

• Airplane: 777-200ER / GE90-94B / Under 632.5k lb

• PACK L Status message displayed

– Status message indicates a fault detected in left air conditioning pack

Example



Example Cont’d

Use EICAS Message Cross Reference ListCross Reference for PACK L Status Message is MMEL Item 21-51-01



MMEL Item 21-51-01

• Flight Restriction

• Operational Limitation

• Performance Adjustment

Example Cont’d



• Flight Restriction:

– Restricted to an altitude of 35,000 ft to maintain an acceptablesmoke clearance capability

• Operational Limitation:

– NCF analysis indicates that if the remaining pack fails, it is possible for flight deck temperatures to reach levels that are unacceptable for extended flight beyond 60 minutes

• Performance Adjustment:

– Reduced thrust when operating in single pack configuration.

Example Cont’d



• Two factors result in reduced airplane thrust capability:

– Single pack operating on higher flow schedule draws additional bleed air from the associated engine and reduces the associated engine's thrust capability. The Thrust Mode Computer (TMC) resets the thrust limit within the opposite engine's Electronic Engine Control (EEC) to maintain symmetric airplane thrust.

– Single pack "works harder" on a high flow schedule so the ASCPC commands FAMV fully open. Associated EEC reduces thrust limit to protect EGT margin. Opposite engine EEC's thrust limit is reset by the TMC to maintain symmetric airplane thrust.

Example Cont’d



• Operator required to ensure airplane meets all applicable performance requirements

• Airplane performance adjustment expressed as:

– Takeoff limited weight decrement (obstacle limited or climb limited)

– Enroute Climb limited weight decrement

– Landing limited weight decrement (approach climb or landing climb)

• Boeing DDG denotes adjustments to be considered in the airplane performance analysis

Example Cont’d



DDG Item21-51-01 (O)

Reduce performance limited weights by the amounts given in the table, or use packs off takeoff.

Example Cont’d



Multiple Inoperative Items

• MEL dispatch with multiple inoperative items is potentially problematic

– Complex system interrelationships and compounded effects

– Affect on crew workload

• Dispatching with multiple inoperative items may be symptomatic of poor airplane maintenance

– FAA MMEL Preamble requires reducing MEL items to a minimum


Summary






Summary

• Airplanes can be legally dispatched for revenue operations with inoperative equipment

• MEL dispatch capability improves airline economics, operations, schedule

• Safety is maintained by appropriate application of restrictions, limitations, and performance adjustments

• Proper application of the MEL requires a thorough understanding of integrated airplane systems architecture

– Incorrect application of performance adjustments could adversely affect safety, or over-penalize airplane performance adversely affecting airline economics

FLIGHTOPERATIONS

ENGINEERING


End ofDispatch Deviations

Performance Engineer Operations CourseBoeing Commercial Airplanes

FLIGHTOPERATIONS

ENGINEERING


High Altitude Operations

Page 1

Magaly CruzPerformance Engineering Operations

Boeing Commercial AirplanesSeptember 2009



• Technical Issues

• Documentation Sources

• Hardware Changes

• Case Study



• High Altitude Operations is any time the airport pressure altitude exceeds Basic AFM Section 1.0 Limitation on Maximum Takeoff / Landing pressure altitude (typically 8,400 ft msl)

• Basic AFM performance data is only valid up to the stated Maximum Takeoff / Landing pressure altitude (typically 8,400 ft msl)

• Performance data above Basic AFM limits are found in AFM High Altitude Appendix “Operation at Airport Pressure Altitudes up to ________ feet”

What Constitutes High Altitude Operations?



• High TAS at high altitude results in high ground speeds

• Tire speed ratings become critical

• Brake Energy can become critical on takeoffs

• Brake Cooling can become critical on landings

• Fuse Plug melt becomes possible after normal landings

• Cabin Altitude Warning Horn logic may need modification (horn sounds at 10,000 ft cabin alt. normally)

What are the Technical Issues for High Alt. Ops?



• High enroute terrain is common, dictates EO driftdown, Emergency Descent, passenger O2 analysis

• Passenger Chemical Oxygen Generators may be inadequate (12 minutes generators standard)

• ETP and PNR becomes a factor in flight planning

• Auto Mask Drop logic may need modification (masks drops at 14,000 ft cabin alt. normally)

• APU start capability should be verified before engine shutdown

• Crew procedures for Pressurization Control may be different

Technical Issues (continued)



• FMC V-speeds may be invalid at extreme high altitude airports (e.g. NG FMC V-speeds valid from -2,000 ft to 13,500 ft msl)

• Only certain Flaps can be used for takeoffs / landings (757: F5 / F25, NG: F1 / F15)

• Engine thrust lapse with increasing altitude results in reduced permissible TOW’s

• High TAS results in high turn radius in possibly tight terrain, esp. important for EO turnback maneuvers




• ISA + 30 deg C is not uncommon for high altitude airports in the Summer

• Landing above 10,000 ft, Cockpit crew should put on their O2 masks at top-of-descent (TOD)

• Climbing out at the FAR Min. Climb gradient (2.4% for twins) at high elevation airports results in astonishingly high ground speeds



High Altitude OperationsTrue Airspeed Effects at High Altitudes

ISA Temperature

50

100

150

200

250

300

350

400

50 100 150 200 250

INDICATED AIRSPEED - KIAS

TRU

E A

IRS

PE

ED

- K

TAS

Sea Level 5,000 ft10,000 ft15,000 ft

Airport Pressure Altitude

• + 4 KTAS/10°C Above ISA

757-200 Brake Energy Limit VMBE @ 99,675 kg

737-700 Brake Energy LimitVMBE @ 62,550 kg

225 mph TireSpeed Limit



Let’s review the 737NG


AFM Section 1 – Operational Limits (737NG)High Altitude Operations


High Altitude OperationsAFM Section 1 – Operational Limits (737NG)


High Altitude OperationsAFM Section 4 - Environmental Envelope (737NG)







Let’s review the 757


High Altitude OperationsAFM Section 1 – Operational Limits (757)




High Altitude OperationsAFM Appendix 10 – Operational Limits (757)






High Altitude OperationsOperations Manual – APU System Description (757)



• No APU Limitation words in 757 AFM Section 1

• 757 APU does have operating limits:– Up to 17,000 ft msl (Bleed air only)– Up to 42,000 ft msl (Electrical load only)– Up to 17,000 ft msl for both Bleed air & Electrical load, up

to 42,000 ft msl for Electrical load

• This is because APU is not considered essential equipment for in air use (except under MEL or ETOPS qualification reasons). Intended for on-ground use only

• Don’t be fooled by no “apparent” Limitations when designing crew procedures

APU Can Provide Cabin Pressurization Up to 17,000 ft Max (757)




High Altitude OperationsAFM Section 4 -

Environmental Envelope (757)AFM Appendix 10 -

Environmental Envelope (757)


High Altitude OperationsHigh Altitude Takeoff Speeds Must be Used


High Altitude OperationsHigh Altitude Takeoff Climb Gradients Must be Used



• Some models will have a High Altitude Appendix(757, 767, 747 Classics, 737 Classics, 727)

• Some models will NOT have a High Altitude Appendix(737NG, 767-400, 777, 747-400, 7E7)

• Some models (eg. 757) impose flap usage Limitations in the AFM, while other models (eg. 737NG) may not.

• Some models (eg. 737NG) stipulate APU operating Limitations in the AFM, while other models (eg. 757) may not.

• Must look beyond documentation variations and check multiple data sources (OM, FCTM, FPPM, DDG, STAS, etc) and then apply real “operational” sense into your procedures

Summary of Documentation Sources



Let’s review Hardware Changes


High Altitude OperationsHigh Altitude Landing Switch (757)


High Altitude Landing Switch (757)High Altitude Operations


High Altitude OperationsHigh Altitude Landing Switch (757)



• (9) 115 scf graphic composite cylinders (1,600 psi) located in aft cargo compartment with (9) individual pressure regulators

• Remote fill system along the right hand aft side wall of the aft cargo compartment (up to 12 cylinders possible)

• Low pressure main distribution loop and distribution system plumbing

• Wiring for O2 indication and deployment system

• Flt deck O2 control module on overhead P5 panel

High Altitude Oxygen System Components (737NG)


High Altitude OperationsChemical Oxygen Generator Supply Profile



Case study

757


High Altitude OperationsExample of High Terrain Over Route


High Altitude OperationsRapid Decompression Over High Terrain


High Altitude OperationsEngine Failure from ETP


High Altitude OperationsEnroute EO Driftdown Followed by EO MA at 11,720 ft Airport


High Altitude OperationsHigh Alt. EO Departure Procedure Can be Complicated


High Altitude OperationsHigh Alt. EO Departure Procedure Can be Complicated


High Altitude Operations737-700 Landing at 14,220 ft Elevation Airport (Bangda)


High Altitude OperationsMade it!!



Thank You

FLIGHTOPERATIONS

ENGINEERING

For Training Purposes Only © Copyright 2009 Boeing

Operations in Mountainous Terrain:Part 1: Intro & Terrain Data

Phil CaloraPerformance Engineer Operations Course

Boeing Commercial AirplanesMarch 2009

1


Issues with Mountainous Terrain

• Engine Failures– Airplane cannot maintain cruise altitude– Airplane must descend to some achievable level off altitude– Airplane must meet regulatory terrain clearance

requirements in pre-flight planning

• Cabin Depressurization– Mountainous terrain may prevent immediate descent to a

safe altitude– Pilots and Passengers require oxygen until a safe altitude

can be reached (10,000 feet)– Airplane oxygen supply must meet the regulatory

requirements for both Crew and Passengers

• Must provide the Pilots with pre-flight dispatch planning to get the passengers and airplane safely to an airport

2


Goals• Understand the basic concepts of Driftdown and

Depressurization/Emergency descents over terrain• Understand the Part 25 & 121 Regulations involved• Understand the different types of data Boeing has

available and the assumptions involved with the data• Understand the types of oxygen systems available on

Boeing airplanes• Understand difference between dispatch and operational

data• Understand the importance of choosing the correct

oxygen system• This course can’t cover every issue involved in a detailed

analysis• It will give you an understanding of the issues and

analysis process


Sources of Terrain Data


Terrain Elevation Sources

• Flight Planning Service - Route profile

• Jeppesen High Altitude Charts

• Jeppesen Low Altitude Charts

• Governmental Terrain Charts

• Operation Navigational Charts (ONC)

• Tactical Pilotage Charts (TPC)

• United States Geological Survey (USGS) - Shuttle Radar Topography Mission (SRTM) Digital Elevation Model, typically used by Boeing


Jeppesen Low Altitude Chart

The Minimum Enroute Altitude is the minimum altitude to clear all obstacles within +/- 5 statute miles of the route by at least 2000 feet and also assures acceptable navigational signal coverage.

MEA = 18,000 ft

Grid MORA = 17,700 ft

The Grid Minimum Off Route Altitude is the minimum altitude to clear all obstacles within the grid area by at least 2000 feet.

196

177

113181

223

223


Jeppesen Low Altitude Chart

The Minimum Obstruction Clearance Altitude (MOCA) is the lowest published altitude between radio fixes on VOR airways, off-airway routes, or route segments which satisfy obstacle clearance requirements between the fixes specified. It is followed by a ‘T’when specified (13500T).

The Minimum Off Route Altitude (MORA) represents altitudes which provide the required clearance over terrain located within 10 nm of the route segment. It is followed by an ‘a’ when specified (17900a) – it is wider than the MOCA

MOCA = 13,500 ft

MORA = 17,900 ft


Jeppesen High Altitude Chart

196

223

Only MEAs which are higher than the floor (usually FL180 –FL220) of the upper airspace are depicted.

113


USGS Shuttle Radar Topography Mission (SRTM)

• Free Digital Elevation Model (DEM)

• http://srtm.usgs.gov/

• Available in 1- and 3-arc second resolutions, depending on region of the world

• Based on Space Shuttle radar data from February of 2000

• This is the method used by Boeing for terrain analysis


Sample Terrain

Buenos Aires

Panama City

Panama City (PTY)to

Buenos Aires (EZE)

Lookup Terrain using:•Grid MORA•SRTM Digital Elevation Model


Grid MORAPanama City

45

14 74

10 51

53

26 179

196


Route Terrain Definition

0

5

10

15

20

25

30

0 500 1000 1500 2000 2500 3000

Distance from Panama City (Nm)

Pres

sure

Alti

tude

(100

0 Fe

et)

JeppesenGrid MORA

SRTM Terrain Height (5 mile corridor half-width)

FLIGHTOPERATIONS

ENGINEERING


Operations in Mountainous Terrain:Part 2: Engine-Out Driftdown



1


Agenda

• Description

• Part 25 Regulations

• Driftdown Profiles

• Driftdown Performance Sources

• Part 121/JAR-OPS Regulations

• Analysis Flow Chart

• Sample Analysis

• Additional Information

2


Engine Inoperative Effect on Thrust, Drag and Climb Capability

Climb Capability(θ): sin(θ) = T – DW

Velocity

θ

Weight

Lift

Thrust

Drag

All Engines Operating

Thrust > DragPositive Climb Capability

Velocity

θ

Weight

Lift

Thrust

Drag*

Thrust < DragNegative Climb Capability

Descend Until Thrust > = Drag

Engine Inoperative

*Increment included for control, windmilling, and spillage drag


Driftdown Scenario

Engine fails

Set MCT thrust

Maintain level flight, decelerate to driftdown speed

Maintain driftdownspeed

Positive Climb Capability

Thrust >= DragDrag > Thrust


Reference of Applicable Regulation

Airplanes: turbine engine powered: En route limitations: two engines inoperative121.193

Airplanes: turbine engine powered: En route limitations: one engine inoperative121.191

En route Flight Paths25.123

Federal Aviation Regulations (FAR)

En-route – Aeroplanes with three or more engines, two engines inoperativeJAR-OPS 1.505

En-route – One engine inoperativeJAR-OPS 1.500

En route Flight Paths25.123

Joint Aviation Requirements (JAR)

Two power-units Inoperative (applicable only to aeroplanes with four power-units). 4.2

One power-unit Inoperative4.1

ICAO, Annex 6, Part 1, Attachment C


Regulations:Net Flight Path (FAR/JAR 25.123)

• Defines manufacturer supplied enroute flight path data• The actual (gross) enroute flight path must be calculated in the most conservative

airplane configuration• Consumption of fuel and oil during driftdown is included• The net flight path data is the actual performance diminished by the following

gradients:

Net driftdownflight path*

Gross driftdownflight path

4 Engine Airplanes

3 Engine Airplanes

2 Engine Airplanes

1.6 %

1.4 %

1.1%


0.5 %

0.3 %

-

2 Engines Inoperative

Enroute Gross to Net Gradient Reduction


Sources of Engine Inoperative Flight Path Data

• Boeing provides many sources of Engine Inoperative flight path data– Airplane Flight Manual (AFM)– Flight Planning and Performance Manual (FPPM)– Operations Manual – Performance Inflight Section (PI)– Operations Manual – Performance Dispatch Section (PD)– Boeing Performance Software (BPS)

• These various sources contain different types of data– Gross vs. Net– Low Speed (certified) vs. High Speed Drag Polars

• The certified net flight path data must be used for engine-inoperative terrain clearance dispatch planning (Part 25)


Regulatory vs. Operational Engine Inoperative Flight Path Data

Flight Test Data

Apply Required Gradient

Decrement

AFM Certified Enroute Data

(FAR/JAR 25.123)

Available in Paper AFM’s and AFM-DPI

High Speed Drag Polar

No Gradient Decrement

Actual (gross) Enroute

Performance Data

Available in Ops Manual (PI Section)

Optimum Driftdown Speed Any Speed

Any Gradient Decrement

Actual (gross) or Net Enroute Performance

Data

Available in Boeing

Performance Software (BPS)

Optimum Climb Speed (Picked by

Manufacturer)

Boeing Performance

Software (BPS)

FPPM Charts, OM (PD)• Net Level Off Weight• Driftdown Profiles

Low Speed (Certified) Drag Polar

Regulatory/Dispatch Operational


Engine Inoperative Terrain Clearance:Net Data for Dispatch

Boeing Performance Software (BPS)• Gross/Net Driftdown Profile• Any speed• Any gradient decrement• Low Speed or High Speed Drag

Polar

Airplane Flight Manual:• Enroute Climb Speeds – 1 and 2 engines inoperative• Enroute Climb Gradients – 1 and 2 engines inoperative• Enroute Climb Weights – 1 and 2 engines inoperative

Available in paper AFM charts and AFM-DPI

Flight Planning and Performance Manual (FPPM):• Net Level Off Weight Chart• Driftdown Profiles Net Flight Path


0

5

10

15

20

25

30

35

40

0 50 100 150 200 250 300 350 400

Distance (Nm)

Pres

sure

Alti

tude

(100

0 Fe

et)

Gross versus Net Flight Path

Initial GW = 70,000 kg

Initial GW = 50,000 kg

• 737-700W / CFM56-7B24/26• Standard Day / No Wind• Optimum Driftdown Speed• Max Continuous Thrust

32,670 ft

27,880 ft

23,940 ft

17,900 ft

Gross PerformanceNet Performance


Low Speed vs. High Speed Drag Polar

0

5

10

15

20

25

30

35

40

0 50 100 150 200 250 300 350 400 450

Distance (Nm)

Pres

sure

Alti

tude

(100

0 Fe

et)

5055

60

Initial Gross Weight (1000 kg)

6570

• 737-700W / CFM56-7B24/26• Standard Day / No Wind• Optimum Driftdown Speed

High Speed Drag PolarLow Speed Drag Polar

The low-speed polar level off height may not always be below the high-speed polar level off height for all airplanes and conditions.


Driftdown Speed Comparison

0

5

10

15

20

25

30

35

40

0 50 100 150 200 250 300 350 400 450

Distance (Nm)

Pres

sure

Alti

tude

(100

0 Fe

et)

Optimum Driftdown SpeedLRC

VMO/MMO

Driftdown Speed

• 737-700W / CFM56-7B24/26• Standard Day / No Wind• Net Flight Path• Max Continuous Thrust• 60,000-kilograms


ETOPS Area of Operation for Various Descent Speeds

Optimum Driftdown Speed1100 Nm

LRC1125 Nm

330 KIAS1215 Nm

737-700W / CFM56-7B180-Minute Area of OpsInitial Gross Weight: 60,000 kg


Regulations: Enroute Limitations: One Engine Inoperative


Enroute Limitations: One Engine Inoperative

No person may take-off at a weight that is greater than that which will allow compliance with the following paragraphs:

There is a positive slope (climb gradient) at 1,500 feet above the landing airport

1.500(a)121.191(a)(1)121.191(a)(2)

RuleJAR-OPS Paragraph

FAR Paragraph

Conditions:• Use one engine inoperative, en route net flight path data from the AFM• Use expected ambient enroute temperatures

ORThe net flight path allows the airplane to continue flight from the cruising altitude to an airport, clearing all terrain and obstructions within a required distance of the intended track by at least 2,000 feet vertically

Assume:•The engine fails at the most critical point•Adverse winds are accounted for

1.500(c)121.191(a)(2)

There is a positive slope (climb gradient) at an altitude of at least 1,000 feet above all terrain within a required distance of the intended track

1.500(b)121.191(a)(1)AND



There is a positive slope (climb gradient) at 1,500 feet above the landing airport

1.500(a)121.191(a)(1)121.191(a)(2)

RuleJAR-OPS Paragraph

FAR Paragraph

Negative Slope:Requirement Not Met

1500 ftLanding Airport

Engine Failure

Positive Slope: Requirement Met

1500 ft

Engine Failure

Landing Airport

To meet requirement:• Reduce weight• Use lower altitude airport



Net Level Off Height

Point of Engine FailureCruise Altitude

The net level off height must clear all terrain by 1,000 feet along the intended track from the point of engine failure to the landing airport

1000 ft

There is a net positive slope (climb gradient) at an altitude of at least 1,000 feet above all terrain within a required distance of the intended track

1.500(b)121.191(a)(1)Rule

JAR-OPS Paragraph

FAR Paragraph



The net flight path allows the airplane to continue flight from the cruising altitude to an airport, clearing all terrain and obstructions within a required distance of the intended track by at least 2,000 feet vertically

1.500(c)121.191(a)(2)Rule

JAR-OPS Paragraph

FAR Paragraph

Cruise Altitude

Engine Failure

2000 ft

Net Flight Path

Gross Flight Path

2000 ft



Point of Engine FailureCruise Altitude

Net Level Off Height (Beginning of Cruise – Heavy Weight)

Point of Engine Failure

Net Level Off Height (Mid-Cruise – Lighter Weight)

Weight decreases as fuel burns

Level-off height increases at lower

weights


Regulations: Enroute Limitations:Two Engines Inoperative

Applicable to 3- and 4-engine airplane models


Enroute Limitations:Two Engines Inoperative

No person may take off at a weight that is greater than that which will allow compliance with either of the following paragraphs:

OR

The AFM net flight path data must permit the airplane to fly from the point where two engines simultaneously fail to a suitable airport, with the net flight path clearing all terrain and obstructions by 2,000 feet within some required distance on either side of the intended trackANDThere is a positive slope (climb gradient) at 1,500 feet above the landing airport

Assume:•The engine fails at the most critical point

1.505(b)121.193(c)(2)

There is no place along the intended track that is more than 90 minutes (with all engines operating at cruise power) from a suitable airport

1.505(a)121.193(c)(1)Rule

JAR-OPS Paragraph

FAR Paragraph

Conditions:• Use two engine inoperative, en route net flight path data from the AFM• Use expected ambient enroute temperatures• Normal fuel and oil consumption can be assumed


Enroute Limitations: Two Engines Inoperative

London

Singapore

Kerman

Paris

RomeAnkara

Tabriz

Karachi

Mumbai

Chennai

Medan

• FAR 121.193(c)(1) / JAR OPS (a)is satisfied because the route stays within 90 minutes of an airport

• Two-engine inoperative driftdownanalysis is not required

Circles represents 90-minutes from an airport at normal all-engine cruise conditions


Enroute Limitations: Two Engines Inoperative

London

Singapore

Kerman

Paris

RomeAnkara

Tabriz

Karachi

Mumbai

Chennai

Medan

• FAR 121.193(c)(1) / JAR OPS (a)is not satisfied because the route is not always within 90 minutes of an airport

• Two-engine inoperative driftdownanalysis is required

Circles represents 90-minutes from an airport at normal all-engine cruise conditions


Enroute Limitations: Track WidthsDriftdown Analysis

Intended Track

Track HalfWidth

13.5 Nm (25 km)CAAC5 Nm (9.3 km)JAA

4.3 Nm (8 km)FAATrack Half-Width by Regulator


Driftdown Analysis Procedure

Does the Net Level Off

Height Clear All the

Terrain Along the Route?

Driftdown Complete

No

Consider Alternate Solutions:• Re-routing• Escape Paths• Reduce Payload

Calculate Net Level off Height

at Takeoff Gross Weight

No

Yes


at the Actual Weight at the Critical Point




Calculate the Engine-Out

Driftdown Profile at the Actual Weight at the Critical Point

Does the Driftdown

Profile Clear the Terrain by

2,000-feet?

Yes

Yes

No

Generate Terrain Elevation Data

Create Details for

Flight Plan


Sample Driftdown Analysis

Buenos Aires

Panama City

Panama City (PTY)to

Buenos Aires (EZE)• 737-700W / CFM56-7B• TOW: 70,000-kilogram• Standard Day (ISA)• 126 Passengers


Route Terrain Definition - SRTM

0

5

10

15

20

25

0 500 1000 1500 2000 2500 3000


Pres

sure

Alti

tude

(100

0 Fe

et)






Driftdown Complete

No




No

Yes








Does the Driftdown


2,000-feet?

Yes

Yes

No


Create Details for

Flight Plan


Net Level Off Height at MTOW

4

6

8

10

12

14

16

18

20

22

24

26

28

30

0 500 1000 1500 2000


Net Level Off Height Must Have 1,000-foot Clearance Above the Terrain

Terrain+1000-ft

70,000 kilograms

(MTOW)





Driftdown Complete

No


No

Yes








Does the Driftdown


2,000-feet?

Yes

Yes

No


Create Details for

Flight Plan





Calculate Weight over Mountainous Terrain

0

5

10

15

20

25

30

35

40

0 500 1000 1500 2000 2500 3000


Pres

sure

Alti

tude

(100

0 Fe

et)

60,500-kilograms


Net Level Off Height at Cruise Weight

4

6

8

10

12

14

16

18

20

22

24

26

28

30

0 500 1000 1500 2000


Terrain+1000-ft

60,500 kilograms










Driftdown Complete

No


No

Yes



Does the Driftdown


2,000-feet?

Yes

Yes

No


Create Details for

Flight Plan





Calculation of Driftdown Profile

FPPM: Driftdown Profiles

or

BPS


Driftdown Profile from BPS

0

5

10

15

20

25

30

35

40

0 50 100 150 200 250 300 350 400

Ground Distance from Engine Failure (Nm)

Pre

ssur

e Al

titud

e (1

000

Feet

)

Conditions:• Initial Weight: 60,500 kilograms• Initial Altitude: 37,000 feet• Max Lift-to-Drag Speed• Standard Day• ~26 knot Headwind

(85% Annual Between PTY & EZE)


0

5

10

15

20

25

30

35

40

0 500 1000 1500 2000 2500 3000


Pres

sure

Alti

tude

(100

0 Fe

et)

Driftdown Profile over Terrain

Critical point can be moved

because of margin

Terrain+2000-ft



Does the Driftdown


2,000-feet?








Driftdown Complete

No


No

Yes



Yes

Yes

No


Create Details for

Flight Plan





0

5

10

15

20

25

30

35

40

0 500 1000 1500 2000 2500 3000


Pres

sure

Alti

tude

(100

0 Fe

et)

Example Text of Dispatch Pilot Procedures

Terrain+2000-ft

• Prior to PAZ (S16 30.7 W068 14.0): Divert on Track to Puerto Maldonado• After PAZ (S16 30.7 W068 14.0): Divert on Track to Salta

Panama City

Buenos Aires

Salta

Waypoint ‘PAZ’

PAZ

Puerto Maldonado


Additional Information


Other Considerations: Turn Radius

5 Miles (4.3 Nmi)FAA Regulations

Terr

ain

Cor

ridor

Wid

th

Engine Failure / DecompressionInitiate Turn

Radius of Turn

F(TAS,Bank Angle)

The airplane may exit the terrain corridor during a turn.

Track

4.2

6.3

11.0

Radius(Nmi)

13.235º

19.925º

34.515º

Distance(Nmi)

Bank Angle

At Cruise Altitude:FL350, Mach 0.78,

After Driftdown:FL250, 235 IAS,

2.4

3.7

6.3

Radius(Nmi)

7.735º

11.525º

20.115º

Distance(Nmi)

Bank Angle

Distance of Turn


Turn Direction

A left hand turn flysover a MOCA of 24,800-feet

A right hand turn flysover MOCA’s of 20,300-feet and 12,500-feet



Bank Angle, φ

L

L•cos(θ) •sin(φ)

L•cos(θ) •cos(φ)W

sin(θ) = T – DW

Lift (L) must increase as bank angle increases. Drag increases with Lift, causing climb angle (and thus climb gradient) to decrease

L= W _cos(θ) •cos(φ)

VClimb Path Angle, θ



Gross Flight Path, No TurnInitiate Turn

End Turn

Climb capability is reduced during a turn, which may decrease, or eliminate, clearance above mountainous terrain

Gross Flight Path, With Turn



40000

35000

30000

25000

150000 50 100 150 200 250 300

Range, nmi

Altitude,ft

No turn

Net performance

15 bankTurn25 bankTurn35 bankTurn

757-200/RB211-535E4

Terrain envelope20000

FLIGHTOPERATIONS

ENGINEERING


Operations in Mountainous Terrain:Part 3: Oxygen Requirements



1


Agenda• Description

• Oxygen Requirement Types

• Passenger Oxygen– Chemical Oxygen Systems– Gaseous Oxygen Systems– Regulations

• Crew Oxygen– System Description– Regulations

• Descent Profiles

• References

• Minimum Flight Altitudes

• Analysis Flow Chart

• Sample Analysis

• Additional Information


Cabin Depressurization Scenario

Depressurization

Don Oxygen Masks

Extend speedbrakes, descend at VMO/MMO

Retract speedbrakes, level off at lowest safe altitude

Extend speedbrakes, descend at VMO/MMO

Retract speedbrakes, level off at lowest safe altitude or 10,000 feet

• A sufficient oxygen supply must be available to meet the passenger and crew requirements

• The descent profile must meet the regulatory minimum flight altitude requirements

• FCOM specifies emergency descent speed of VMO/MMO• Cruise speeds are at set at the discretion of the airline;

Boeing recommends turbulent air penetration speeds (VA)


Oxygen Requirement Types

There are Two Types of Requirements for Oxygen:

• Supplement Oxygen– Protects against hypoxia in the case of a

depressurization or loss of cabin altitude– Oxygen required is altitude dependent (higher oxygen

flow rate is required at higher altitudes)– Required for both flight crews and passengers

• Protective Oxygen– Protects against smoke and harmful gas inhalation in

the case of a fire, etc– Required for flight crews only, not for passengers


FAA and JAA Passenger Oxygen Requirements

Between 10,000 and 14,000 feet, oxygen is required for 10-percent of the passengers for the part of the flight that is greater than 30-minutes duration

1.770(b)(2)(i)121.329(c)(1)

(See 121.333(e))

RuleJAR-OPSParagraph

FAR Paragraph

Above 15,000, oxygen is required for 100-percent of the passengers for the entire part of the flight at those altitudes

1.770(b)(2)(i)121.329(c)(3)

Between 14,000 and 15,000 feet, oxygen is required for 30-percent of the passengers for the entire part of the flight at those altitudes

1.770(b)(2)(i)121.329(c)(2)

The passenger oxygen system must supply sufficient oxygen to passengers in accordance with the following conditions:

Between 10,000 and 14,000 feet, oxygen is required for 10-percent of the passengers for the entire flight at those altitudesSupersedes FAR 121.329(c)(1)

-121.333(e)Rule

JAR-OPSParagraph

FAR Paragraph

For Turbine Powered Airplanes:

For Turbine Powered Airplanes with Pressurized Cabins:


Regulations

10,000 feet

15,000 feet

Max Operating Altitude

10% of Passengers Require Oxygen*

30% of Passengers Require Oxygen

All Passengers Require Oxygen

No Passenger Oxygen Required

14,000 feet

Does not include first aid oxygen requirements* JAA Only: 10% Passenger oxygen is required only after the first 30 minutes at these altitudes

Below 10,000 feet


Passenger Chemical Oxygen System Description

• 12-minute or 22-minute System

• Descent profile limited by oxygen system envelope– Specific to FAA and JAA

operators

• Limited flexibility and capability for high altitude terrain

• Lighter weight than gaseous system


Chemical Oxygen System Descent Envelopes: 12-minute versus 22-minute Systems

0

5

10

15

20

25

30

35

40

45

0 5 10 15 20 25 30

Time (Minutes)

Pres

sure

Alti

tude

(100

0 fe

et) 22-minute

chemical system

12-minute chemical system

25000 feet

27000 feet

10000 feet

41000 feet• 737-700W• FAA Regulations

17000 feet


Chemical Oxygen System Descent Envelopes:FAA vs. JAA Regulations

0

5

10

15

20

25

30

35

40

45

0 5 10 15 20 25 30 35 40 45 50

Time (Minutes)

Pres

sure

Alti

tude

(100

0 fe

et)

FAA Regulations

17000 feet

10000 feet

41000 feet

14000 feet

30 min

• 737-700W• 12-minute System

There is no physical difference in the oxygen system, only the regulations are different

JAR-OPS Regulations: Oxygen is not needed for the first 30 minutes at 14,000 feet


Oxygen System Envelope Compared to the Airplane Descent Profile

0

5

10

15

20

25

30

35

40

45

0 5 10 15 20 25 30

Time (Minutes)

Pres

sure

Alti

tude

(100

0 fe

et)

• 737-700W• 22-minute System• FAA Regulations• VMO/MMO Emergency Descent

Airplane Descent Profile

Oxygen System Envelope

The airplane descent profile cannot follow the oxygen envelope descent exactly. Airplane emergency descent profile is affected by airplane weight, thrust, speed, atmosphere, thrust, so must stay WITHIN the specified envelope. Thus may not be able to take full advantage of the envelope.


Passenger Gaseous Oxygen System Description

• Flexible descent profiles

• Oxygen cylinders are optimized to meet the passenger oxygen requirements– Not specific to FAA and JAA operators

• Greater capability and flexibility than the chemical system for operations over high terrain

• Increased weight over the chemical system


Gaseous Oxygen Descent Profile Comparison

0

5

10

15

20

25

30

35

40

0 10 20 30 40 50 60

Time (Minutes)

Pres

sure

Alti

tude

(100

0 fe

et)

Higher Altitudes Require More Oxygen

To minimize required oxygen, descend to lower altitudes as soon as possible

Gaseous systems allow any descent profile to be flown.

Depressurization


Choosing a Passenger Oxygen System

• Need to consider current and future routes – Gaseous versus Chemical systems.

• System retrofits can be difficult and costly – Boeing does not retrofit from Chemical to Gaseous system.

• Boeing will assist you in deciding which system is best for you.

BEFORE BUYING THE AIPRLANE

When is the best time to Perform a passenger oxygen analysis?


Flight Crew Oxygen System• Flight crew requires gaseous oxygen system

• Oxygen cylinder is pressurized to meet the flight crew oxygen requirements

• Oxygen quantity requirements and cylinder pressure requirements are provided in the FPPM

• Oxygen is consumed during flight. Bottles need to be refilled.

• EMERG Used for protective breathing• 100% Used for supplemental/descent• NORMAL Used after descent (level off)

3 Settings


FAA Crewmember Oxygen RequirementsThe flight crew oxygen system must supply sufficient oxygen to crew members in accordance with the following conditions:

Between 10,000 and 12,000 feet, oxygen is required for the part of the flight greater than 30-minutes duration

Supplemental121.329(b)(1)Rule

Oxygen TypeFAR Paragraph

Above 12,000 feet, oxygen is required for each crewmember during the entire flight

Supplemental121.329(b)(2)

A minimum two-hour supply of oxygen for each crew member, assuming a descent to 10,000-feet in 10-minutes, followed by 110-minutes at 10,000-foot cabin altitude

Supplemental121.333(b)

A 15-minute supply of protective breathing for each crew member at a normal cabin pressure altitude of 8,000 feet, for protection against smoke

Protective121.337(b)(7)

10,000 feet

12,000 feet


Between 10,000 & 12,000 ft, Oxygen Required After 30 min.

Oxygen Required for Entire Time Above 12,000 feet

No Crew Oxygen Required


JAR-OPS Crewmember Oxygen Requirements

Above 13,000 feet, oxygen must be supplied for the entire flight time

Between 10,000 feet and 13,000 feet, oxygen is required for the part of the flight greater than 30-minutes duration

The oxygen supply will not be less than, a two-hour supply of oxygen for each crew member, assuming a descent to 10,000-feet in 10-minutes, followed by 110-minutes at 10,000-foot cabin altitude

Supplemental1.770(b)(1)(i)Rule

Oxygen TypeJAR-OPS Paragraph

A 15-minute supply of protective breathing for each crew member

Protective1.780(a)(1)

The flight crew oxygen system must supply sufficient oxygen to crewmembers in accordance with the following conditions:

10,000 feet

13,000 feet


Between 10,000 and 13,000 feet, Oxygen Required After 30-minutes

Oxygen Required for Entire Time Above 13,000 feet (for FAA it is 12,000 feet)

Below 10,000 feet, No Crew Oxygen Required


Flight Crew Breathing Requirements

FPPM: Aircraft with Chemical Passenger Oxygen Systems

This table meets the FAR 121.333(b) and JAROPS 1.770(b)(1)(i) requirement for a minimum of two-hours of crewmember oxygen, as well as the requirements of FAR 121.337(b)(7) or JAROPS 1.780(a)(i) requirement for 15 minutes of protective oxygen, whichever is the greater

Note:FAR 121.329(b)(1),(2) and JAROPS 1.770(b)(1)(i) requirements do not impact Flight Crew Oxygen when the airplane is equipped with a chemical oxygen system. The minimum of two-hours of oxygen meets the requirements for both the 12-minute or 22-minute chemical system descent envelope.



FPPM: Aircraft with Gaseous Passenger Oxygen Systems

Table 1 meets the requirements of FAR 121.337(b)(7) or JAROPS 1.780(a)(i) requirement for 15 minutes of protective oxygen

Tables 2 & 3 meet the FAR 121.329(b)(1),(2) and JAROPS 1.770(b)(1)(i) requirements to supply oxygen for the actual flight time

The crewmember oxygen requirement is the greater of the Table 1 oxygen OR the Table 2 + Table 3 oxygen calculation Table 2 meets the

FAR 121.333(b) and JAROPS 1.770(b)(1)(i) requirement for a minimum of two hours of crew member oxygen (as the table does not go less than two hours)



Enter table with required liters of oxygen, then determine required cylinder pressure

FPPM: Aircraft with Chemical or Gaseous Passenger Oxygen Systems


Constructing a Depressurization Descent Profile

0

5

10

15

20

25

30

35

40

45

0 5 10 15 20 25 30

Time (Minutes)

Pres

sure

Alti

tude

(100

0 fe

et)

1. Use BPS to calculate the emergency descent profile between each intermediate cruise altitude2. Determine the maximum allowed cruise time at each intermediate altitude

1 minute

2.5minutes

11.5 minutes

37000 feet Initial Altitude

22-minute chemical systemenvelope


Constructing a Depressurization Descent Profile

0

5

10

15

20

25

30

35

40

45

0 20 40 60 80 100 120 140 160 180 200

Distance (Nm)

Pres

sure

Alti

tude

(100

0 fe

et)

Combine Emergency Descent and Cruise Segments

2.5minutes

11.5 minutes

37000 feet Initial Altitude1 minute

• 737-700W• VMO/MMO Emergency Descent• VMO/MMO Cruise


Airplane Descent Profiles Vary with Weight

0

5

10

15

20

25

30

35

40

45

0 5 10 15 20 25 30

Time (Minutes)

Pres

sure

Alti

tude

(100

0 fe

et)

Airplane Descent Profile(70,000 kg)

Oxygen System Envelope

Emergency descent profiles for lighter weights are steeper, and allow more time at higher cruise altitudes.

Airplane Descent Profile(50,000 kg)

• 737-700W• 22-minute System• FAA Regulations• VMO/MMO Emergency Descent


Cabin Depressurization Terrain Clearance:Data Sources

Boeing Performance Software (BPS)• Emergency descent profile• Any speed• Any weight• All engine, flaps up, gear up, spoilers up configuration

Flight Planning and Performance Manual (FPPM):• Crew oxygen requirements• Passenger chemical oxygen system envelope• Passenger gaseous oxygen requirements


Regulations: Minimum Flight AltitudesOxygen System Analysis

In designated mountainous areas, no person may operate an aircraft within 2,000 feet above the highest obstacle within a horizontal distance 5 statue miles from the center of the intended course

-121.657(c)

Provides examples of available methods for calculating minimum flight altitudes. A clearance of 2,000 feet is generally recommended for all terrain and obstacles above 6,000 feet within a horizontal distance of 5, 10, and up to 30 nautical miles from the center of the intended course

IEM 1.250-

RuleJAR-OPSParagraph

FAR Paragraph

Intended TrackTrack Half Width

13.5 Nm (25 km)CAAC

5 Nm (9.3 km)10 Nm (18.5 km)30 Nm (55.6)

JAA4.3 Nm (8 km)FAA

Track Half-Width by Regulator


Oxygen Requirements Analysis Procedure(Chemical System)

Yes

Generate Terrain

Elevation Data

Is there Terrain

above 8,000 feet

(assuming 2,000 ft margin)

Yes

Oxygen AnalysisComplete

Create Details for

Flight Plan

Are On-Route

Alternate Airports

Available?

Have the Critical

Regions Been

Eliminated?Generate

Depressurization Descent Profile

Are there Any Critical Regions?

Plot Descent Profile Over

TerrainAre Off-Track

Alternates Available

via Escape Routes?

Have the Critical

Regions Been

Eliminated?

No

Yes

Yes

No Yes

No

YesNo

No

Consider Alternate Solutions:• Re-routing• Higher Capacity Oxygen

System


Oxygen Requirements Analysis Procedure(Gaseous System)

Determine the Desired Number of Critical Points

Is there Terrain

above 8,000 feet



Create Details for

Flight Plan

Generate Terrain

Elevation Data

No

Yes

Assemble Descent Profile(s) to Clear

the Terrain

Is the Required

Number of Oxygen

Cylinders Acceptable

?

Plot Descent Profile over

Terrain and Verify the Terrain is

Cleared Safely

Calculate the Crew and Passenger

Oxygen Requirements

Adjust the Critical Points


the Terrain

NoYes


Sample Oxygen System Analyses

1. Passenger Chemical Oxygen System Analysis

2. Passenger Gaseous Oxygen System Analysis

3. Crew Oxygen System Analysis


Passenger Chemical Oxygen System Analysis

Buenos Aires

Panama City

Panama City (PTY)to

Buenos Aires (EZE)• 737-700W / CFM56-7B

TOW: 70,000-kilogram• Standard Day (ISA)• 126 Passengers• 22-Minute Chemical

Oxygen System• FAA Rules



0

5

10

15

20

25

0 500 1000 1500 2000 2500 3000


Pres

sure

Alti

tude

(100

0 Fe

et)



Yes

Generate Terrain

Elevation Data

Is there Terrain

above 8,000 feet


Yes


Create Details for

Flight Plan

Are On-Route

Alternate Airports

Available?

Have the Critical

Regions Been

Eliminated?Generate




TerrainAre Off-Track


via Escape Routes?

Have the Critical

Regions Been

Eliminated?

No

Yes

Yes

No Yes

No

YesNo

No


System


Descent Envelope for 22-Minute Chemical Oxygen System


Generate Depressurization Descent Profile

0

5

10

15

20

25

30

35

40

45

0 5 10 15 20 25 30

Time from Depressurization (Min)

Pre

ssur

e Al

titud

e (1

000

Feet

)

The depressurization descent profile was assembled in BPS:Descent:• Spoilers Up Configuration• VMO/MMO• Weight is not a significant factorCruise:• Determine cruise times at each altitude to remain within Oxygen

Envelope• Use VMO/MMO to maximize distance

Oxygen SystemEnvelope




0

5

10

15

20

25

30

35

40

0 50 100 150 200 250

Ground Distance from Depressurization (Nm)

Pre

ssur

e Al

titud

e (1

000

Feet

)


0

5

10

15

20

25

30

35

40

0 500 1000 1500 2000 2500 3000


Pres

sure

Alti

tude

(100

0Oxygen Requirements Analysis Procedure

(Chemical System)

DIK

UN

OR

OK

O

Critical RegionContinue To Buenos Aires

(Fuel Permitting)Return to

Panama City

Critical Region:Cannot Return to Panama City

orContinue to Buenos Aires

Consider:1. Enroute alternate airports2. Escape routes/Off-track

alternate airports3. Re-routing4. Gaseous Oxygen System



Create Details for

Flight Plan


Are On-Route

Alternate Airports

Available?

Have the Critical

Regions Been

Eliminated?


Are Off-Track


via Escape Routes?

Have the Critical

Regions Been

Eliminated?

YesNo

No


Terrain


System

Yes

Yes

No Yes

YesNo

NoYes

Generate Terrain

Elevation Data

Is there Terrain

above 8,000 feet




Critical Region and Enroute Alternates

Buenos Aires

Panama City

Iquitos

La Paz

Salta

Critical Region

DIKUN

Oroko


First Mountainous Region

0

5

10

15

20

25

30

35

40

0 500 1000 1500 2000 2500 3000


Pres

sure

Alti

tude

(100

0

Iquitos


0

5

10

15

20

25

30

35

40

0 100 200 300 400 500 600 700 800 900 1000


Pres

sure

Alti

tude

(100

0First Mountainous Region

First point fromwhich diversion to IquitosIs Possible(Waypoint Asiko)

Point of No Return – Last point from which course reversal is possible(Waypoint Dikun)

Both course continuation or reversal are possible

IquitosPanama City


Second Mountainous Region

0

5

10

15

20

25

30

35

40

0 500 1000 1500 2000 2500 3000


Pres

sure

Alti

tude

(100

0

Iquitos

La Paz


0

5

10

15

20

25

30

35

40

1400 1500 1600 1700 1800 1900 2000 2100 2200


Pres

sure

Alti

tude

(100

0Second Mountainous Region

Last point fromwhich return to IquitosIs Possible(Waypoint PAZ)

Diversion to La Paz

First point fromwhich continuation to Buenos Aires Is Possible(Waypoint Oroko)

Critical Region – No available Airports

La Paz

Last point from which diversion to La Paz is possible(S18 52.7 W067 18.9)


Critical Region and Enroute Alternates

Buenos Aires

Panama City

Iquitos

La Paz

Salta

DIKUN

OrokoStill have a critical between(S18 52.7 W067 18.9) and Oroko

S18 52.7 W067 18.9



Create Details for

Flight Plan


Are On-Route

Alternate Airports

Available?

Have the Critical

Regions Been

Eliminated?


Are Off-Track


via Escape Routes?

Have the Critical

Regions Been

Eliminated?

YesNo

No


Terrain

Yes

Yes

No Yes

YesNo

NoYes

Generate Terrain

Elevation Data

Is there Terrain

above 8,000 feet




System



La Paz

Salta

Sucre

Oroko

S18 52.7 W067 18.9

Possible Solution:• For every point between

S18 52.7 W067 18.9 and Oroko, divert to Sucre

• Analyze diversions every 10 statute miles along the track (2 x corridor width)

• Do not only consider the beginning and end of the critical region

10 statute miles


S18 52.7 W067 18.9 to Sucre

0

5

10

15

20

25

30

35

40

0 50 100 150 200 250

Distance (Nm)

Pres

sure

Alti

tude

(100

0 Fe

et)

La Paz

Salta

Sucre

Oroko

S18 52.7 W067 18.9

Terrain+2000-ftSucre

S18 52.7 W067 18.9


Oroko to Sucre

0

5

10

15

20

25

30

35

40

0 50 100 150 200 250

Distance (Nm)

Pres

sure

Alti

tude

(100

0 Fe

et)

La Paz

Salta

Sucre

Oroko

S18 52.7 W067 18.9

Terrain+2000-ft

Sucre

Oroko

TERRAIN NOT CLEARED!



Yes

Create Details for

Flight Plan


Are On-Route

Alternate Airports

Available?

Have the Critical

Regions Been

Eliminated?


Are Off-Track


via Escape Routes?

Have the Critical

Regions Been

Eliminated?

YesNo

No


Terrain

Yes

Yes

No Yes

No

NoYes

Generate Terrain

Elevation Data

Is there Terrain

above 8,000 feet




System







Passenger Gaseous Oxygen System Analysis

Buenos Aires

Panama City

Panama City (PTY)to

Buenos Aires (EZE)• 737-700W / CFM56-7B• TOW: 70,000-kilogram• Standard Day (ISA)• 126 Passengers• Gaseous Oxygen System• FAA Rules




Is there Terrain

above 8,000 feet



Create Details for

Flight Plan

Generate Terrain

Elevation Data

No

Yes


the Terrain

Is the Required

Number of Oxygen


?



Cleared Safely


Oxygen Requirements



the Terrain

NoYes



0

5

10

15

20

25

0 500 1000 1500 2000 2500 3000


Pres

sure

Alti

tude

(100

0 Fe

et)




Is there Terrain

above 8,000 feet



Create Details for

Flight Plan

Generate Terrain

Elevation Data

No

Yes


the Terrain

Is the Required

Number of Oxygen


?



Cleared Safely


Oxygen Requirements



the Terrain

NoYes


Gaseous Oxygen System Profiles with 1 Critical Point

0

5

10

15

20

25

30

35

40

0 500 1000 1500 2000 2500 3000


Pres

sure

Alti

tude

(100

0

Critical Point

1 Critical Point:• Requires most oxygen and oxygen cylinders• Extra weight• Simplest flight-planning• Reduces crew workload following depressurization


0

5

10

15

20

25

30

35

40

0 500 1000 1500 2000 2500 3000


Pres

sure

Alti

tude

(100

0

2 Critical Points:• Reduces Oxygen Requirements• Lower weight than having 1 Critical Point• Additional flight planning required• Increases crew workload following depressurization


Critical PointCritical Point



0

5

10

15

20

25

30

35

40

0 500 1000 1500 2000 2500 3000


Pres

sure

Alti

tude

(100

0

3 Critical Points:• Further Reduces Oxygen Requirements• Lowest weight (least number of Oxygen cylinders)• Additional flight planning required• Increases crew workload following depressurization

Critical PointCritical Point Critical Point

La Paz





the Terrain



Cleared Safely

Is there Terrain

above 8,000 feet



Create Details for

Flight Plan

Generate Terrain

Elevation Data

No

Yes

Is the Required

Number of Oxygen


?


Oxygen Requirements



the Terrain

NoYes


0

5

10

15

20

25

30

35

40

0 500 1000 1500 2000 2500 3000


Pres

sure

Alti

tude

(100

0Sample Calculation of Oxygen

Requirements

155-minutes @ 15,000 Feet

15-minutes @ 23,000 Feet

180-minutes to descend to 10,000-feet(15-minutes + 155-minutes + 10-minutes*)*10-minutes approximates direct descent to 10,000-feet

Critical Point


FPPM Passenger Oxygen RequirementsTotal Oxygen Quantity Required = Table 1 + Table 2


Table 1 Passenger Oxygen Calculation• 126-passengers• 180-minutes to 10,000 feet (3-hours)• Altitude at Decompression of 37,000 feet

35000 37000 39000

100 3070 3175 3280200 6120 6315 6510

Number of Occupants In

Passenger Cabin

Pressure Altitude At Compression

Liters Required

Interpolate for 37,000 ft Pressure Altitude

Pressure Altitude At Compression37000

Liters Required100 3175126 3991200 6315


Passenger Cabin

Interpolate for 126 Passengers


Table 2 Passenger Oxygen Calculations23,000-feet Level-Off

• 126-passengers• 15-minutes @ 23,000 feet

21000 23000 25000100 149 179 209200 298 358 418


Passenger

Additional Oxygen Required (Liters per minute)Intermediate Pressure Altitude

Interpolate for 23,000 ft Pressure Altitude



23000100 179126 226200 358


Passenger Cabin


Table 2 Passenger Oxygen Calculations15,000-feet Level-Off


15000100 13126 16200 26


Passenger Cabin

• 126-passengers• 155-minutes @ 15,000 feet



Total Passenger Oxygen Requirement

23,000 ft: 226 liters per minute x 15 minutes = 3390 Liters

15,000 ft: 16 liters per minute x 155 minutes = 2480 Liters

Total = 5870 Liters

Table 1

Table 2

3991 Liters

Total 9861 Liters


Required Number of Cylinders• Assume Cylinder Pressure of

1500 PSI• Oxygen Volume Required of

9861 Liters• Passenger Cylinder

Requirement = 5







FPPM Flight Crew Oxygen RequirementsTotal Oxygen Quantity Required = Larger of Table 1 or Table 2 + Table 3


Crew Oxygen Calculation• 2-crew• 180-minutes to 10,000 feet (3-hours)• Altitude at Decompression of 37,000 feet


Crew Oxygen Calculation

660 Liters

Table 1 Table 2 + Table 3

Table 2 = 960 Liters

Table 3:23,000 ft 6 liters per minute x 15 minutes = 90 Liters15,000 ft 1 liter per minute x 155 minutes = 155 Liters

Total = 245 Liters

Table 2 + Table 3 = 1205 Liters


Crew Cylinder Pressure

• Oxygen Volume Required of1205 Liters (Table 2 + Table 3)

• Minimum Required Cylinder Pressure of 900 PSI


Additional Information


Available Oxygen Systems by Model

All Minor ModelsAll Minor ModelsAll Minor Models777

All Minor ModelsAll Minor Models767

757-200 Only for China Xinjiang Airlines (XIJ) & China Southwest Airlines (XIN)

All Minor ModelsAll Minor Models757

All Minor Models747

Available on All Minor Models,Currently Only 737-700’s

Operating with Gaseous SystemAll Minor ModelsAll Minor Models737NG

All Minor Models737Classic

Gaseous22-Minute Chemical12-Minute Chemical


Other Considerations: Turn Radius

5 Miles (4.3 Nmi)FAA Regulations

Terr

ain

Cor

ridor

Wid

th

Engine Failure / DecompressionInitiate Turn

Radius of Turn

F(TAS,Bank Angle)

The airplane may exit the terrain corridor during a turn.

Track

4.2

6.3

11.0

Radius(Nmi)

13.235º

19.925º

34.515º

Distance(Nmi)

Bank Angle

At Cruise Altitude:FL350, Mach 0.78,

After Driftdown:FL250, 235 IAS,

2.4

3.7

6.3

Radius(Nmi)

7.735º

11.525º

20.115º

Distance(Nmi)

Bank Angle

Distance of Turn

Practical Exercises for

Operations in Mountainous Terrain

Practical Exercise 1: Assumptions: 767-300 / PW4060 Takeoff Gross Weight: 160,000 kg Gross Weight at entrance to mountainous area: 145,000 kg Flight Altitude: FL350 Temperature: ISA + 10 conditions Terrain on following page Determine the following: Net level off height using takeoff weight: Does this altitude clear the terrain? (remember to include 1,000 ft offset): Net level off height using weight at the entrance to the mountainous area: Does this altitude clear the terrain? (remember to include 1,000 ft offset): If an engine fails at 225 nmi along the route and the airplane is at 140,000 kg, will the driftdown profile clear the terrain? Assume no wind. (remember to include 2,000 ft offset):

Operations in Mountainous Terrain Practical Exercises Page 1

Rout

e Te

rrai

n El

evat

ion

04812162024283236

0

25

50

75

100

125

150

175

200

225

250

275

300

325

350

375

400

Ran

ge (n

mi)

Elevation (1000 ft)

Trac

k W

idth

of ±

5 nm

i

20,8

00 ft

19,3

00 ft


Flight Planning and Performance Manual

FLIGHT PLANNINGDriftdown

767-300/PW4060FAACategory C & D Brakes

Copyright © The Boeing Company. See title page for details.

D632T003-VV679 2.3.1

2.3 FLIGHT PLANNING-DriftdownENGINE INOP

MAX CONTINUOUS THRUSTDriftdown

Net Level Off WeightBased on engine bleed for packs on or off, APU on or off and anti-ice off

With engine anti-ice on, decrease allowable weight by 6000 kg.With engine and wing anti-ice on, decrease allowable weight by 14500 kg.

WEIGHT 1000 KG

100 110 120 130 140 150 160 170 180 190

LEV

EL

OF

F P

RE

SS

UR

E A

LTIT

UD

E

100

0 F

T

0

2

4

6

8

10

12

14

16

18

20

22

24

26

28

30

32

ISA DEVIATION+10 C & BELOW

+15 C+20 C

December 1, 2005FOR TRAINING PURPOSES ONLY. MATERIAL WILL NOT BE KEPT UP-TO-DATE



FLIGHT PLANNINGDriftdown

767-300/PW4060FAACategory C & D Brakes


D632T003-VV679 2.3.3

ENGINE INOPMAX CONTINUOUS THRUST

Driftdown

Driftdown Profiles Net Flight PathBased on engine bleed for packs on or off, APU on or off and anti-ice off35000 FT to 37000 FT

With engine anti-ice on, increase allowable weight by 6000 kg.With engine and wing anti-ice on, increase allowable weight by 14500 kg.

WIN

D

KT

S

GROUND DISTANCE FROM ENGINE FAILURE NM

0 50 100 150 200 250 300100

50

0

50

100

TAIL

HEAD

REF LINE

190

180

170

160

150

140

130

120

110

100

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

5500

PR

ES

SU

RE

ALT

ITU

DE

10

00 F

T

TIME FROM ENGINE FAILURE MIN

0 5 10 15 20 25 30 35 40 45 10

15

20

25

30

35

GR

OS

S W

EIG

HT

AT

EN

GIN

E F

AIL

UR

E10

00 K

G

EQ

UIV

ALE

NT

GR

OS

S W

EIG

HT

AT E

NG

INE

FA

ILU

RE

10

00 K

G

ISA DEV C

10& BELOW

15 20100 100

110 110

120 120

130 130

140 140

150 150

160 160

170 170

180 180

190 190

FUEL BURN FROM ENGINE FAILURE KG

EQUIVALENT GROSSWEIGHT AT ENGINEFAILURE 1000 KG

December 1, 2005FOR TRAINING PURPOSES ONLY. MATERIAL WILL NOT BE KEPT UP-TO-DATE


Practical Exercise 2: Assumptions: 777-200ER / GE90-90B Flight Altitude FL310 Temperature = ISA Conditions Terrain on following pages 12 minute chemical oxygen system (profile on following pages) Determine the following: If a depressurization were to occur 200 nmi along the route, will the 12 minute oxygen system safely clear the terrain? (remember to include 2,000 ft offset): If you can not clear the terrain, what will you do:


777-

200E

R/G

E90-

90B

Em

erge

ncy

Des

cent

Pro

file

(12-

Min

ute

Che

mic

al O

xyge

n Sy

stem

)

04812162024283236

010

2030

4050

6070

8090

100

Ran

ge (n

mi)

Elevation (1000 ft)

FOR TRAINING PURPOSES ONLY. MATERIAL WILL NOT BE KEPT UP-TO-DATE


Rout

e Te

rrai

n El

evat

ion

04812162024283236

0

25

50

75

100

125

150

175

200

225

250

275

300

325

350

375

400

Ran

ge (n

mi)

Elevation (1000 ft)

Trac

k W

idth

of ±

5 nm

i

Terr

ain

+ 20

00 ft

Terr

ain


Practical Exercise 3: Assumptions: 747-400 / CFM6-80C2B1F Gaseous passenger activated oxygen system with 21 cylinders Passengers: 400 Flight Altitude: FL430 Ambient Temperature at Dispatch: 21° C (do not apply any temperature corrections) Terrain on following page Determine the following: What level off altitude is required?: How much distance at that altitude is required?: How much time at that altitude is required? (assume 400 KTAS): What total passenger oxygen volume is required to clear the terrain?: What system pressure is required for this volume of oxygen?: What could be done to reduce the passenger oxygen requirement?: What is the protective breathing oxygen volume required for a flight crew of 2?: What is the supplemental breathing oxygen volume required for a flight crew of 2? Assume an airline policy of 100% oxygen setting to 10,000 feet: What is the resulting crew oxygen requirement for this mission?:


Rout

e Te

rrai

n El

evat

ion

04812162024283236

0

100

200

300

400

500

600

700

800

900

1000

1100

1200

1300

1400

Ran

ge (n

mi)

Elevation (1000 ft)

Trac

k W

idth

of ±

5 nm

i

Terr

ain

+ 20

00 ft

Terr

ain

22,8

00 ft



2.2.12 D632U001-RZ001


747-400/CF6-80C2B1FFAA

Category J Brakes

FLIGHT PLANNINGSimplified Flight Planning

Oxygen RequirementsPassenger Activated SystemTable 1

Table 2

NO. OFOCCUPANTS

IN PASSENGERCABIN

TOTAL POST DECOMPRESSION

TIME (HOURS)

PRESSURE ALTITUDE AT DECOMPRESSION (FT)20000 27000 31000 35000 39000 43000 45000

LITERS REQUIRED

100

.17** 830 990 1020 1160 1340 1525 16101 960 1190 1265 1435 1650 1880 20002 1410 1640 1715 1885 2100 2330 24503 1860 2090 2165 2335 2550 2780 29004 2310 2540 2615 2785 3000 3230 33505 2760 2990 3065 3235 3450 3680 3800

200

.17** 1660 1980 2040 2280 2620 2965 31201 1920 2380 2530 2830 3240 3675 39002 2820 3280 3430 3730 4140 4575 48003 3720 4180 4330 4630 5040 5475 57004 4620 5080 5230 5530 5940 6375 66005 5520 5980 6130 6430 6840 7275 7500

300

.17** 2490 2970 3060 3400 3900 4405 46301 2880 3570 3795 4225 4830 5470 58002 4230 4920 5145 5575 6180 6820 71503 5580 6270 6495 6925 7530 8170 85004 6930 7620 7845 8275 8880 9520 98505 8280 8970 9195 9625 10230 10870 11200

400

.17** 3320 3960 4080 4520 5180 5845 61401 3840 4760 5060 5620 6420 7265 77002 5640 6560 6860 7420 8220 9065 95003 7440 8360 8660 9220 10020 10865 113004 9240 10160 10460 11020 11820 12665 131005 11040 11960 12260 12820 13620 14465 14900

500

.17** 4150 4950 5100 5640 6460 7285 76501 4800 5950 6325 7015 8010 9060 96002 7050 8200 8575 9265 10260 11310 118503 9300 10450 10825 11515 12510 13560 141004 11550 12700 13075 13765 14760 15810 163505 13800 14950 15325 16015 17010 18060 18600

600

.17** 4980 5940 6120 6760 7740 8725 91601 5760 7140 7590 8410 9600 10855 115002 8460 9840 10290 11110 12300 13555 142003 11160 12540 12990 13810 15000 16255 169004 13860 15240 15690 16510 17700 18955 196005 16560 17940 18390 19210 20400 21655 22300

Total post decompression time includes descent, level off at intermediate altitude ( if applicable) and flight at final level off altitude. Time to shut down 90% masks at 14000 ft pressure altitude is 11 minute.** Minimum post decompression time (10 min) approximates direct descent to 10000 ft pressure altitude.

NO. OFOCCUPANTS IN

PASSENGER CABIN

ADDITIONAL OXYGEN REQUIRED LITERS PER MINUTE ABOVE 14000 FT PRESSURE ALTITUDEINTERMEDIATE PRESSURE ALTITUDE

15000* 17000 21000 25000100 18 123 198 288200 36 245 395 540300 54 368 593 793400 72 490 790 1045500 90 613 988 1298600 108 735 1185 1550

*30% Cabin Occupants using Oxygen.

October 1, 2008FOR TRAINING PURPOSES ONLY. MATERIAL WILL NOT BE KEPT UP-TO-DATE



2.2.14 D632U001-RZ001


747-400/CF6-80C2B1FFAA

Category J Brakes


Oxygen RequirementsFlight Crew SystemTable 1

Table 2

Table 3

NUMBER OF CREW OXYGEN REQUIRED (LITERS)2 6803 10204 1340

Includes normal usage allowance of one man for 15 minutes at 8000 ft.

NUMBER OF CREWOXYGEN REQUIRED FOR LEVEL OFF AT 14000 FT (LITERS)

TOTAL POST DECOMPRESSION TIME (HR)2 3 4 5

2 650 960 1260 15703 980 1440 1900 23604 1310 1920 2530 3150

Includes normal usage allowance of one man for 15 minutes at 8000 ft cabin altitude.

NUMBER OF CREW

ADDITIONAL LITERS REQUIRED FOR EACH MINUTE HELD AT INTERMEDIATE ALTITUDEOTHER THAN 14000 FT

INTERMEDIATE PRESSURE ALTITUDE (FT)8000 to 13999 14000 14001 to 17999 18000 to 21999 22000 to 25000

REGULATOR ON "NORMAL" OR (100%)2 0 (22) 0 (16) 1 (16) 3 (12) 4 (11)3 0 (33) 0 (24) 1 (24) 4 (18) 6 (16)4 0 (43) 0 (32) 2 (32) 5 (25) 8 (21)

Instructions:1. Determine protective breathing requirements from Table 1.2. Determine sustenance requirements for level off at 14000 ft from Table 2 and correct for level off altitudes other than 14000 ft using

Table 3.3. Flight crew system oxygen requirements are the larger of protective breathing (Table 1) or sustenance requirements (Table 2).





747-400/CF6-80C2B1FFAACategory J Brakes


D632U001-RZ001 2.2.15

Oxygen RequirementsCylinder Volume to Pressure Conversion

Minimum Cylinder Pressure Required

Temperature Corrections

CYLINDER PRESSURE@ 21°C (70°F)

(PSI)

NUMBER OF 114 CUBIC FOOT BOTTLES INSTALLED1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22

OXYGEN IN CYLINDERS (1000 LITER)100 .1 .1 .1 .1 .2 .2 .2 .2 .3 .3 .3 .3 .4 .4 .4 .4 .5 .5 .5200 .1 .3 .5 .7 .9 1.1 1.3 1.5 1.7 1.9 2.1 2.3 2.5 2.7 2.9 3.1 3.3 3.5 3.7 3.9 4.1 4.3300 .3 .7 1.1 1.4 1.8 2.2 2.6 2.9 3.3 3.7 4.0 4.4 4.8 5.2 5.5 5.9 6.3 6.7 7.0 7.4 7.8 8.1400 .5 1.0 1.6 2.1 2.7 3.2 3.8 4.3 4.9 5.4 6.0 6.5 7.0 7.6 8.1 8.7 9.2 9.8 10.3 10.9 11.4 12.0500 .7 1.4 2.1 2.8 3.5 4.3 5.0 5.7 6.4 7.1 7.9 8.6 9.3 10.0 10.7 11.5 12.2 12.9 13.6 14.3 15.1 15.8600 .8 1.7 2.6 3.5 4.4 5.3 6.2 7.1 8.0 8.9 9.8 10.7 11.6 12.4 13.3 14.2 15.1 16.0 16.9 17.8 18.7 19.6700 1.0 2.1 3.1 4.2 5.3 6.3 7.4 8.5 9.5 10.6 11.7 12.7 13.8 14.9 15.9 17.0 18.1 19.1 20.2 21.3 22.3 23.4800 1.2 2.4 3.7 4.9 6.1 7.4 8.6 9.9 11.1 12.3 13.6 14.8 16.1 17.3 18.5 19.8 21.0 22.3 23.5 24.7 26.0 27.2900 1.4 2.8 4.2 5.6 7.0 8.4 9.8 11.3 12.7 14.1 15.5 16.9 18.3 19.7 21.1 22.6 24.0 25.4 26.8 28.2 29.6 31.01000 1.5 3.1 4.7 6.3 7.9 9.5 11.1 12.6 14.2 15.8 17.4 19.0 20.6 22.2 23.7 25.3 26.9 28.5 30.1 31.7 33.3 34.81100 1.7 3.5 5.2 7.0 8.7 10.5 12.3 14.0 15.8 17.5 19.3 21.1 22.8 24.6 26.3 28.1 29.9 31.6 33.4 35.1 36.9 38.71200 1.9 3.8 5.7 7.7 9.6 11.5 13.5 15.4 17.3 19.3 21.2 23.1 25.1 27.0 28.9 30.9 32.8 34.7 36.7 38.6 40.5 42.51300 2.1 4.2 6.3 8.4 10.5 12.6 14.7 16.8 18.9 21.0 23.1 25.2 27.3 29.4 31.5 33.6 35.8 37.9 40.0 42.1 44.2 46.31400 2.2 4.5 6.8 9.1 11.3 13.6 15.9 18.2 20.5 22.7 25.0 27.3 29.6 31.9 34.1 36.4 38.7 41.0 43.3 45.5 47.8 50.11500 2.4 4.9 7.3 9.8 12.2 14.7 17.1 19.6 22.0 24.5 26.9 29.4 31.8 34.3 36.7 39.2 41.6 44.1 46.5 49.0 51.5 53.91600 2.6 5.2 7.8 10.5 13.1 15.7 18.3 21.0 23.6 26.2 28.8 31.5 34.1 36.7 39.3 42.0 44.6 47.2 49.8 52.5 55.1 57.71700 2.7 5.5 8.3 11.1 13.9 16.7 19.5 22.3 25.1 27.9 30.7 33.5 36.3 39.1 41.9 44.7 47.5 50.3 53.1 55.9 58.7 61.51800 2.9 5.9 8.9 11.8 14.8 17.8 20.8 23.7 26.7 29.7 32.6 35.6 38.6 41.6 44.5 47.5 50.5 53.5 56.4 59.4 62.4 65.31900 3.1 6.2 9.4 12.5 15.7 18.8 22.0 25.1 28.3 31.4 34.6 37.7 40.8 44.0 47.1 50.3 53.4 56.6 59.7 62.9 66.0 69.22000 3.3 6.6 9.9 13.2 16.5 19.9 23.2 26.5 29.8 33.1 36.5 39.8 43.1 46.4 49.7 53.1 56.4 59.7 63.0 66.3 69.7 73.0

CREWSYSTEM PASSENGER SYSTEM

Check minimum/maximum pressure in shaded area.Maximum cylinder pressure = 1850 psi at 21°C (70°F).For maximum cylinder pressure at hotter or colder temperatures add or substract 32 PSI per 5°C (10°F) respectively.

NUMBER OF 114 CU FT CYLINDERS

MINIMUM PRESSURE REQUIRED (PSI)

CREW1 6802 680

PASSENGER3 8104 7805 7506 7207 6908 670

9 THROUGH 22 640

CYLINDER PRESSUREAT 21°C (70°F)

(PSI)

PRESSURE CORRECTIONFOR EACH 5°C (10°F)*

(PSI)400 7600 11800 141000 171200 211400 241600 281800 312000 34

* If ambient temperature above 21°C (70°F), add increment shown. If ambient temperature below 21°C (70°F), subtract increment shown.



Answers to Practical Exercises


Practical Exercise 1: Assumptions: 767-300 / PW4060 Takeoff Gross Weight: 160,000 kg Gross Weight at entrance to mountainous area: 145,000 kg Flight Altitude: FL350 Temperature: ISA + 10 conditions Terrain on following page Determine the following: Net level off height using takeoff weight: ~18,200 ft Does this altitude clear the terrain? (remember to include 1,000 ft offset): No Net level off height using weight at the entrance to the mountainous area: 20,800 ft Does this altitude clear the terrain? (remember to include 1,000 ft offset): No If an engine fails at 225 nmi along the route and the airplane is at 140,000 kg, will the driftdown profile clear the terrain? Assume no wind. (remember to include 2,000 ft offset): Yes


Practical Exercise 2: Assumptions: 777-200ER / GE90-90B Flight Altitude FL310 Temperature = ISA Conditions Terrain on following pages 12 minute chemical oxygen system (profile on following pages) Determine the following: If a depressurization were to occur 200 nmi along the route, will the 12 minute oxygen system safely clear the terrain? (remember to include 2,000 ft offset): No If you can not clear the terrain, what will you do: Look for escape paths, change the routing, look to retrofits to a 22 minute chemical system.


Practical Exercise 3: Assumptions: 747-400 / CFM6-80C2B1F Gaseous passenger activated oxygen system with 21 cylinders Passengers: 400 Flight Altitude: FL430 Ambient Temperature at Dispatch: 21° C (do not apply any temperature corrections) Terrain on following page Determine the following: What level off altitude is required?: 22,800 feet (FL210) How much distance at that altitude is required?:400 nm in each direction (800 total) How much time at that altitude is required? (assume 400 KTAS): 1 hour What total oxygen volume is required to clear the terrain?: 7,265 liters (Table 1) + 60 min × 917.5 liters/minute (Table 2) = 62,315 liters What system pressure is required for this volume of oxygen?: ~1800 psi What could be done to reduce the passenger oxygen requirement?: Minimize the level off altitudes, change routing around the terrain, look for escape paths and off track alternate airports What is the protective breathing oxygen volume required for a flight crew of 2?: 680 liters (Table 1) What is the supplemental breathing oxygen volume required for a flight crew of 2? Assume an airline policy of 100% oxygen setting to 10,000 feet: 340 liters (Table 2) + 60 min × 12 liters/minute (Table 3) = 1310 liters What is the resulting crew oxygen requirement for this mission?: 1310 liters


FLIGHTOPERATIONS

ENGINEERING


Runway Loading

John ChristyPerformance Engineering Operations

Flight Operations EngineeringBoeing Commercial Airplanes

September 2009


Performance Limits

1. Field Length Limit

2. Climb Limit

3. Obstacle Limit

4. Tire Speed Limit

5. Brake Energy Limit

6. Pavement Strength Limit

7. Airport Noise Limit


Relationship of Aircraft to Pavement

• Loading the pavement

• Rating the pavement

• Life of the pavement

• Runway Roughness

• Ongoing Research


Pavement Loading

• Pavement loading refers to the load an airport runway, taxiway, or ramp area is subjected to by the airplane’s main landing gear.

• About 2/3 of the worlds larger airports have flexible pavement runways.

FlexiblePavement

Asphalt

Base/ Subbase

Natural Soil

RigidPavement

Concrete

Base/ Subbase

Natural Soil


Runway Loads - Takeoff / LandingTypical Jet Aircraft

Distance

Runway pavements are designed for static load.

The impact of landing is only about 38% of the takeoff static load.

Run

way

load

% m

ax ta

xi

100

80

60

40

20

0

TAKEOFF LANDING


Insufficient Pavement Strength?


Not Typical Failure


Typical Result of Pavement Overload


Pavement Rating

Purpose of the Pavement Rating

• To match the aircraft traffic with the pavement so that the design life is reached.

• To assure a practical, economical pavement life.

• To provide a convenient method of comparing aircraft loads to allowable pavement capacity.

• Today, many if not most, airports publish out of date pavement ratings! Such ratings are usually lower than the true pavement strength.


Pavement Rating

• Pavement rating is derived from:– An evaluation of the pavement through

engineering tests and traffic history, or – Optionally, the aircraft currently using the airport.

(Note: the pavement could be stronger).

• Pavement engineering is a complex subject.

• Airplane safety is not involved.


Pavement Rating

• Pavement Rating Types:– ESWL: Equivalent Single Wheel Load – Obsolete– LCN: Load Classification Number – Obsolete– AUW: All Up Weight – Obsolete– FAA: All Up Weight by Gear type

– ACN/PCN: ICAO Standard since 1981


Pavement Rating

• ACN (Aircraft Classification Number): Describes the relative load intensity of an airplane’s main landing gear.

What is ACN?


Aircraft Rating

Basis for ACN

• ACN was adopted by ICAO and member nations as the official method for reporting a relative comparison of airplane loading intensity.

• ACN replaces all previous methods by which manufacturers report their aircraft loading characteristics.

• ACN is not pavement design.


Aircraft Classification Number – ACN

The ACN’s of an airplane are calculated as follows:

• The Portland Cement Association computer program “PDILB” is used to calculatethe concrete thickness required for standard conditions using:

Standard

Conditions

• Basic airplane characteristics

• Concrete working stress = 2.75 MN/m² (400 PSI)

• Concrete Modulus of Elasticity E = 27,580 MPa (4,000,000 PSI)

• Reference thicknesses are calculated for the 4 standard subgrade K values.A standard rigid pavement chart with the reference thickness is then used to find ACN.

• The U.S. Corps of Engineers method S-77-1 is used to calculate the pavementthicknesses required for standard conditions using:

Standard

Conditions

• Basic airplane characteristics

• 10,000 coverages

• Reference thicknesses are calculated for the 4 standard subgrade CBR values

• A standard flexible pavement chart with the reference thickness is then used to find ACN

Flexible

The basic airplane characteristics used above are:

Gear Load

Gear Geometry

Tire Pressure

• Max. aft C.G. limit at max. gross weight is used for all weights

• Number of wheels and spacing

• As published by manufacturer

Rigid

ONLY Aircraft Manufacturers Calculate ACN's!


Pavement Rating

What is PCN?

• PCN (Pavement Classification Number): Describes the actual load-carrying capacity of an airport runway, taxiway or ramp


Pavement Rating

Basis for PCN

• PCN was adopted by ICAO and member nations as the official method for reporting airport pavement strength.

• PCN replaces all previous methods by which airport authorities report their pavement capabilities.

• PCN is not pavement design.


Pavement Classification Number – PCNAirport authority evaluates pavement by any means and determines the gross weight limit of a critical airplane which will result in the desired pavement life at the expected traffic level.

Data reported (published in AIP) examples: PCN 50 RCXT or 37 FBYU

• PCN

• Pavement type

A number from 1 to 100 or larger; a PCN 100 pavement is stronger than a PCN 90 pavement, assuming the same pavement type and subgrade category.

• Subgrade category

CodeA (High)B (Medium)C (Low)D (Ultra low)

CBR RangeAbove 138 to 134 to 8Less than 4

Standard151063

Standard150804020

Modulus K RangeAbove 120 MN/m3

60 to 120 MN/m3

25 to 60 MN/m3

Less than 25 MN/m3

• Default value - code B will be assumed if subgrade is not specified.

• Tire pressure Due to local conditions, airport authority may choose to specify a tire pressure limit(usually applicable to thin asphalt surfaces)

– Code W - No tire pressure limit– Code X - 1.5 Mpa maximum (218 PSI)– Code Y - 1.0 Mpa maximum (145 PSI)– Code Z - 0.5 Mpa maximum (73 PSI)

Default value - code X will be assumed if tire pressure limit is not specified

Code T - Technical evaluationCode U - Based on experience from using aircraft

• Method of evaluation

Code F - Flexible Code R - Rigid

ONLY Airport Authorities Publish PCN's!


PCN ACN72RBWT

Rating Number2 types of Pavement

4 strengths of soil support 4 tire pressure ranges2 types of basis for evaluation

ACN ≤ PCN means Unrestricted MTOW

Pavement Rating

What is ACN/PCN?

• ACN (Aircraft Classification Number): Describes the relative load intensity of an airplane’s main landing gear.

• PCN (Pavement Classification Number): Describes the actual load-carrying capacity of an airport runway, taxiway or ramp.


Pavement Rating

• ACN’s are determined by airplane manufacturers: – Published in Airplane Characteristics for Airport

Planning documents. – Also shown in ICAO Annex 14 and Jeppesen.

• PCN’s are established by the airport authorities of the various nations:– Published in the Aeronautical Information Publications (AIP). – Also shown in the Jeppesen Airport Directory.– Airports are the only authority to allow or disallow aircraft

usage of the pavement.


PCN Data: Jeppesen Example

3 Airports All: PCN 56/F/A/W/T

Abha (OEAB) PCN 56 F/A/W/T


Boeing Airport Technology: ACN DataAirport Planning Manuals Available

www.boeing.com/airports


ACN Data


ACN Data

Abha (OEAB) PCN 56 F/A/W/T

715,000 lbs (325 tonnes)

660,000 lbs (300 tonnes)

PCN 56 FBXT


ACN Data


PCN Data: AIP Example

Brasil Free AIP data online: seehttp://www.aisweb.aer.mil.br/aisweb/














Pavement Life

• Typical pavement design life is 20 years.

• Pavement life is a function of original design, number of aircraft operations, aircraft loads, and maintenance.

• Historically, pavements increase in load carrying capacity by the following:– Rigid pavements are reconstructed periodically to

accommodate heavier aircraft.– Flexible pavements are typically overlaid every 10 to

14 years on average (primarily to correct for weathering). Each overlay adds life to the pavement because it increases the cross-sectional thickness.


Pavement Life

ICAO Simplified Pavement Life Criteria

• For flexible pavements, occasional movements by aircraft with ACN not exceeding ten percent above the reported PCN should not adversely affect the pavement life.

• For rigid, occasional movements by aircraft with ACN not exceeding five percent above the reported PCN should not adversely affect the pavement life.

• If the pavement structure is unknown, the five percent limitation should apply to both cases above; and

• The annual number of overload movements in all cases should not exceed approximately five percent of the total annual aircraft movements.


Pavement Life

777 Flexible Pavement Life

Shows the effect of a 2-inch overlay on pavement life

PCN 59 FB

t-=32”

20

30

40

50

60

70

80

ACN

300 400 500 600 700 800Gross weight, 1,000 lb

20

30

40

50

60

70

80

100 1,000 10,000 100,000 1,000,000Annual Departures

PCN

Example PavementCBR 10 Subgrade20-year Pavement LifeS-77-1 Design

t=30”

5,000 15,000

777-300ERCode B SubgradeACN Program


777 Rigid Pavement Life

Shows the effect of a 1-inch increase in thickness on pavement life

30

40

50

60

70

80

90

ACN

300 400 500 600 700 800Gross weight, 1,000 lb

30

40

50

60

70

80

90

100 1,000 10,000 100,000 1,000,000Annual Departures

PCN

Example PavementK= 300 pci Subgrade20-year Pavement LifePCA Design

T=14”777-300ERCode B SubgradeACN Program

PCN 74 RB

T=15”

1,300 4,200

Pavement Life


346767.34 Gervais

Runway Roughness: Alaskan Bump


Long Wave Roughness


Effect of Excessive Roughness

MAY:– Affect instrument readability for pilot– Affect steering control– Reduce landing gear and aircraft

structural life– Impose a .4g vertical acceleration force

on the aircraft


Boeing Runway Roughness Criteria

Bump length, m

Bump height, cm

Acceptable

0 10 20 30 40 500

5

10

15

20

Excessive

60

RUNWAY ROUGHNESS CRITERIAL

H

L

H

L

H

Unacceptable


Ongoing Research- NAPTF Test Machine


Summary

• Pavement strength ratings, when properly analyzed and published, will allow:

1) pavement to support the expected aircraft traffic for the desired design life (normally 20 years).

2) airlines to optimize aircraft operations to eliminate unnecessary weight restrictions (payload penalties).

3) airlines evaluate the viability of prospective airportsas potential destinations.

• Many airports worldwide currently publish out of date (artificially low) pavement strength ratings.

• Boeing Airport Technology is available to help resolve these issues. Pavement Ratings are not absolute.