Manufacturer’s Perspective- Airport Pavement Nd dMit ...Nd dMit INeeds and Maintenance Issues Michael Roginski, PE Principal Engineer Boeing Airport Technology VII ALACPA Airport
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Manufacturer’s Perspective- Airport Pavement N d d M i t INeeds and Maintenance Issues
Michael Roginski, PE
Principal Engineer
Boeing Airport Technology
VII ALACPA Airport Pavement Seminar
Miami, FL
December 6-9, 2010
OutlineOutline
Trends in current aircraft design- effect on pavement design
Aircraft compatibility with airports- concerns of the manufacturer and airline customers
Pavement maintenance issues- effect on aircraft and airlines
Manufacturer’s involvement with industry and regulators to address pavement issues and establish standardspavement issues and establish standards
Trends in Current Aircraft Design
ACN Aircraft Timeline (Gross Wt)ACN-Aircraft Timeline (Gross Wt)
1,400,000
ICAO Adopted
ACN/PCN
A3801,200,000
method
747-400
B747-8001,000,000
gh
t (l
b)
Commercial fleet when ACN/PCN, method
adopted
B777-300ER
A340-600
B747800,000
Gro
ss W
eig
B777MD-11
B787-8
400,000
600,000
Air
pla
ne
G
Commercial fleet since the ACN/PCN method
B707
DC-8
B727
Convair 880
COMET 4200,000
ACN/PCN, method adopted
Constellation Viscount YS-11B-17
HeronDC-3
0
1930 1940 1950 1960 1970 1980 1990 2000 2010 2020
ACN Aircraft Timeline (Wheel load)ACN-Aircraft Timeline (Wheel load)
A340-600
70000
ICAO Adopted
ACN/PCN method
B777-300ER
MD-11 B787-8B747-800
A38060000
methodCommercial fleet when
ACN/PCN, method adopted
747-400
B777B747
40000
50000
Lo
ad (
lb)
DC-8
B727 COMET 4
CONSTELLATION VISCOUNT B-17
30000
40000
ane
Wh
eel
L
B707CONVAIR 880
CONSTELLATION YS-11
HERON
DC-3
20000
Air
pla
Commercial fleet since the ACN/PCN, method
adopted
DC 3
10000
0
1930 1940 1950 1960 1970 1980 1990 2000 2010 2020
Year Aircraft Introduced
Tire Pressure Trend
16 517.0
15.2
16.1
15.7
15 0
16.1
15.2 15.2
16.5
16.0
r)
14.1
14.4
15.0
14.0
15.0
essu
re (
ba
r
12.4 12.513.0
Tir
e P
re
11.7 11.711.9
11.0
12.0
) ) 0) ) ) ) ) 0) ) 0) ) ) ) ) )
727-
200
(19,
300)
737-
300
(13,
700)
767-
300E
R (21,
600)
A300-
C4 (1
9,30
0)
777-
200
(19,
300)
737-
700
(16,
100)
A320-
200 (1
8,00
0)
777-
300E
R (27,
200)
A340-
600 (2
7,40
0)
747-
400E
R (24,
200)
A380-
800 (2
6,70
0)
A380-
800F (2
8,100
)
787-
8 (2
5,20
0)
747-
8 (2
6,20
0)
A350-
900 (3
0,80
0)
Aircraft (SWL-kg)
80’s 90’s FUTURECURRENT
Trends in Pavement LoadingACN FB*
80
90
70
80
747 400DC 10/MD11
CONCORDELR 777
A380A340-600
747-8
787-8
787-9
767-400ER
50
60ACN
New Aircraft707
DC8-63
L10-11
747-400
A300
DC-10/MD11
A310
777 -300A330
A340
767-300
747-400ER
30
40
New Aircraft
707
707
747-100
777 (A MARKET)
767-200
FLEXIBLE PAVEMENT ACN'S ARE BASED ON ALPHA
20
1950 1960 1970 1980 1990 2000 2010 2020
Year in Service
FACTORS APPROVED BY ICAO IN OCTOBER 2007
*FB – Flexible (asphalt pavement) on a medium-strength subgrade
Year in Service
How does the Aircraft Manufacturer Design for Pavement Loading
•Develop an initial ACN requirement based on the trend line and similar aircraft
• Preliminary size the landing gear geometry to be compatible with subgrade code B and C airports- ~ 70% of all airports
• If the ACN falls below trend line- consider future derivative growth and If the ACN falls below trend line consider future derivative growth and higher weights and assess competitive aircraft
• Target airports determined from marketing must be assessed- goal of 2/3 tibilitcompatibility
• Resizing of gear geometry must take into account aircraft performance
• Problem airports can be worked as they arise based on airline input• Problem airports can be worked as they arise based on airline input
Wingspan Increase Over TimeICAO Design Standards
Wing Span (M)Wing Span (M)
80C o de F < 80 m
80C o de F < 80 m
787-8787-9
747-100
747-400 747-8
60
70
C o de E < 65 m
777-300ER
787-8787-9
747-100
747-400 747-8
60
70
C o de E < 65 m
777-300ER
DC 10 10
DC-10-30MD-11 767-400
787-3EIS TBD
747 100777-2/300
767 Winglets
50 C o de D < 52 m
DC 10 10
DC-10-30MD-11 767-400
787-3EIS TBD
747 100777-2/300
767 Winglets
50 C o de D < 52 m
737 NG 737 Winglets
767-200
757-200 757-300 757 Winglets
767-300DC-10-10
40
C o de C < 36 m 737 NG 737 Winglets
767-200
757-200 757-300 757 Winglets
767-300DC-10-10
40
C o de C < 36 m
737-100 737-300
g
20
30After-Market Winglet
737-100 737-300
g
20
30After-Market Winglet
20
1965 1970 1975 1980 1985 1990 1995 2000 2005 2010 2015
Entry into Service (Year)March 2009
20
1965 1970 1975 1980 1985 1990 1995 2000 2005 2010 2015
Entry into Service (Year)March 2009
Takeoff Field Length
4,0004,000ftft
mm
3,0003,000
12,00012,000
A380-800F
707-320
DC-8-63Concorde
737-300
DC-8-55
DC-10-10
767-400
777-300
DC-10-30
A340-300
A340-200
MD11
747 100
777-300ER
A340-600
747-400
,,
TakeoffTakeoff
8,0008,000737-100
DC 9 15
737-700 727-200A319
A320-200
A321
757
707-120
767-200
A310-300
A300-600 777-200747SP
A300-300
A330-200747-100
A380-800
DC-9-32
2,0002,000Takeoff field length
Takeoff field length
4 0004 000
DC-9-15
717-200
A318
A320-200 757
1,0001,0004,0004,000 DC-3
0000 11 22 33 44 55 66
00kgkg
Gross weight x 10E5Gross weight x 10E500 22 44 66 88 1010 1212lblb
Aircraft Compatibility with Pavement
Aircraft Compatibility with Pavement
What are the manufacturers concerns?:What are the manufacturers concerns?:
Improved design procedures and software to handle today’s heavier aircraft with more complex gear geometries
Standardized pavement rating system (PCN)
- Many old rating systems still in place
- Airlines need accurate PCN ratings in order to assess feasability of operations. Lack of updates to country Aeronautical Information Publication (AIP) does not reflect runway improvements and true bearingPublication (AIP) does not reflect runway improvements and true bearing strength of pavements.
Improved Design Procedures and Software
Pavement Ratings- Confusion between various rating methods
Pavement Rating Types:
ESWL:Equivalent Single Wheel Load – Obsoleteg
LCN: Load Classification Number – Obsolete
AUW: All Up Weight ObsoleteAUW: All Up Weight – Obsolete
FAA: All Up Weight by Gear type-no rating for tridem gearsFAA now requiring PCN ratings for US airportsFAA now requiring PCN ratings for US airports
ACN/PCN: ICAO Standard since 1981
Airport Source Data- Jeppesen Example
How does an airline determine route feasibility for a 777?How does an airline determine route feasibility for a 777?
FAA Gear Rating System
2D landing gears
g y
40Constant Weight (200,000 lbs) - Increasing Departures
2D landing gears
Constant gross load of 200,000 lbs
36
38
avem
ent
.
Changing Wheel Spacing
Which 200k, 2D gear was used to generate an
Same gear typebut with different n
ess
30
32
34
of F
lexi
ble
Pa
2D-20-45
gallowable gear load?
but with differentwheel spacing
ng
Th
ickn
26
28
30
d T
hic
kn
ess
o
2D-20-45
2D-21-46
2D-26-51
Incr
easi
n
22
24
Req
uir
ed
2D-30-55
B-767gear 45-56
A330-300gear 55-78With CBR=5, New Alpha Factors
20
1 10 100 1000 10000 100000
Annual Departures (Log Scale)
p
Increasing Frequency
LCN Rating SystemLCN Rating System
LCN ti t i ll d t t t thi kLCN rating typically does not note pavement thickness, no way to assess pavement loading
PCN Rating System Preferred MethodPCN Rating System- Preferred Method
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 relative load-carrying capacity of an airport runway, taxiway or ramptaxiway or ramp.
PCN ACN72RBWT
Rating Number2 types of Pavement
4 strengths of soil support 4 tire pressure ranges2 types of basis for evaluation
4 strengths of soil support 4 tire pressure ranges
ACN ≤ PCN means Unrestricted MTOW
Industry Need for Standardization
Overlay Effects on Pavement PCN-
777 Flexible Pavement Life
AIP Updates are an Ongoing Process
80 80Example Pavement
PCN
777 Flexible Pavement Life
60
70
60
70777-300ERCode B SubgradeACN Program
PCN 59 FB
CBR 10 Subgrade20-year Pavement LifeS-77-1 Design
t=30”
PCN 66FB
40
50
AC
N
40
50
PCN 59 FBt-=32”
20
30
300 400 500 600 700 80020
30
100 1 000 10 000 100 000 1 000 000
5,000
300 400 500 600 700 800
Gross Weight, 1,000 lb
100 1,000 10,000 100,000 1,000,000
Annual Departures
Sh th ff t f 2 i hShows the effect of a 2-inch overlay on pavement life
Pavement Maintenance Issues
Boeing Bump Criteria-Runway Roughness
20USAF airplane designcriteria MIL-A-008862Apaved airfields
ght,
cm 15 ExcessiveUnacceptable
paved airfields
ump
heig
Acceptable10
Bu
5
Runway vertical curve(ICAO annex 14)
ICAO tolerablelimits (annex 14)
FAA smoothness criteria
0 10 20 30 40 500
60
FAA smoothness criteria
Bump length, mICAO standardof construction
Long Wave DepressionBump Definitionp
Rod Length
5.10Centerline
3C
Rod LengthBump Length
Bump
5.003N
height
Elevation, mNorth
4.90
South3S
6+3046+220 6+250 6+280
4.82
Runway Station, m
Airplane Load Factor Exceedances-Fatigue Life ConcernFatigue Life Concern
100 Takeoff Roll
r fli
ght
10
Landing Rollout
ance
s pe
r 10
Exc
eeda
1.0 Typical Rough RRunway-
Takeoff Roll
Incremental vertical acceleration at CG (g units)
.10
0.2 0.4 0.6 0.8 1.0
Airports Surveyed by Boeingp y y g
Example of Results From W ld id R h T tiWorldwide Roughness Testing
20
16
20
Unacceptable Excessive
Bump
16
12Alaska
Greece
Chile
Canada
u pHeight,
cm8
Canada
Tanzania
South Pacific
Columbia
4Acceptable
Bump Length m
0 10 20 30 40 500
60
CIS
Bump Length, m
757-200 MLG Truck Beam Fracture- Short Wave Roughness Issue
Airline: TransAero (TRX)
Date: June 20th, 1996
Place: Yekaterinburg, Russia
Runway Profile Analysis-Short Wave Roughness3D R l ti P S t l D it3D Relative Power Spectral Density
able
B)
Acc
epta
m)
t P
SD
(d
1500m
Ast
ance
(m
ay H
eig
ht
nw
ay D
is
e R
un
wa
Ro
ug
hR
un
Rel
ativ
e
Bump Wavelength (m)
2 7
Runway Profile Issue- Contaminated Condition
Runway Transverse Cross Sections
Station 0+606Station 0+606
25
30
35
40
cm
0
5
10
15
20
Ele
vation c
-5 0 5 10 15 20 25 30 35 40 45
Runway Width m
Station 0+630
25
30
35
40
n c
m
0
5
10
15
20
Ele
vation
-5 0 5 10 15 20 25 30 35 40 45
Runway Width m
Runway Cross Sections
Station 2+250
15
20
25
30
35on c
m
-5
0
5
10
15
0 5 10 15 20 25 30 35 40 45
Ele
vatio
Runway Width m
Station 2+580
35
10
15
20
25
30
lev
ati
on
cm
0
5
10
0 5 10 15 20 25 30 35 40 45
Runway Width m
E
Boeing Runway Roughness Criteria
Effect on the Customer Airline
Rough runways can affect aircraft landing gear- high vertical acceleration loads caused by long wave roughness cannot exceed limit loads used for design. Often the source of pilot complaints (i.e. shaking g p p ( ginstruments, sudden jolt in pilot seat)
Short wave roughness can lead to excessive heating of truck beam pivot joint leading to potential for failure and requiring increased inspection and lubrication intervals for airlines (i e more cost to airline)and lubrication intervals for airlines (i.e. more cost to airline).
Water impingement due to contaminated runways not meeting properWater impingement due to contaminated runways not meeting proper profile gradient has led to issues for some airlines- replacement spares.
Runway Friction- Slippery Runway Effects on Aircraft Landings
Reference landing distances in flight operations manual based on reported braking action, i.e. good, medium or poor
Correlation of Aircraft Braking With R F i ti M tRunway Friction Measurement
0 5
0 4
0.5
15%15%20%
20%
0.4
0.3
Falcom 20 – Uniform surfaces
Falcom 20 – Other surfaces
Braking Coefficient
0.2Falcom 20 Other surfaces
Boeing aircraft
Turboprop aircraft
Linear fit0.1
Canadian Runway Friction Index
0.2 0.4 0.6 0.8 0.1000
Braking coefficients for all aircraft for all aircraft versus Canadian Runway Friction Index
Canadian Runway Friction Index
Manufacturer Involvement with Industry and R l dd P IRegulators to address Pavement Issues
Airport Authority of India
Airport Authority of IndiaAirport Authority of India
Revised Alpha Factor Curves From the FAA NAPTPFAA NAPTP
1.4
1.2
12-Wheel Failure
12-Wheel Nonfailure
50-kip Single Wheel Failure Alpha = 0.23 log C + 0.15
1.030-kip Single Wheel Failure
30-kip Single Wheel Nonfailure
Dual-Tandem Failure
NAPTF 4 Wheel
Single Wheel
Twin TandemLoading
Repetition Factor, Alpha
0.8
0.6
NAPTF 4-Wheel
NAPTF 6-Wheel 6 Wheels
Alpha
0.4
0 2
1.0E+00 1.0E+01 1.0E+02 1.0E+03 1.0E+040
1.0E+05
0.2
Aircraft Traffic Volume Factor, Coverages
High Tire Pressure Effects on Flexible Pavements-Testing at the NAPTF
ICAO Roughness CurveA d f A 14 V l 1 5th EditiApproved for Annex 14, Vol. 1, 5th Edition
Bump height, cmp g20
Unacceptable
15 ExcessiveUnacceptable
10 Temporarily acceptable
Acceptable5
0 10 20 30 40 500
60Bump length, m
ICAO Activity-ICAO AOSWG Pavement Sub-Group Future Topics
Tire Pressure Classification-categories in ICAO PCN rating system need to be more representative of current aircraft. New tire pressure categories, validated by test, have been accepted pending formal g , y , p p gapproval by ICAO member states.
PCN rating system- lack of guidance in ICAO ADM Part 3. More l l di d t ti t i l i l 80’complex landing gears and newer construction materials since early 80’s
Pavement Overload- current ADM Part 3 has general guidance on permitted overload more precise method may be possible usingpermitted overload, more precise method may be possible using cumulative damage factor (CDF) approach.
Pavement management and inspection procedures should be improved
Improved ACN/PCN methodology-layered elastic method
Conclusions
M f t ’ R l d R ibilitiManufacturer’s Roles and Responsibilities:
Provide ACN’s to airlines for all their commercial products.commercial products.
Airport planning manuals for airports- aid in master planning
Support airlines on pavement loading issues.Support airlines on pavement loading issues.
Provide site-specific support to airlines and airports, as requested. PCN analyses and testing as needed
Responsibility that new aircraft do not exceed limits of current pavement technology- verification by full scale testing
Keep worldwide pavement community abreast of future aircraft technology- airports need to plan for future infrastructure upgrades
Thank You!Thank You!
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