Manufacturer’s Perspective- Airport Pavement N d dMit I Needs and Maintenance Issues Michael Roginski, PE Principal Engineer Boeing Airport Technology VII ALACPA Airport Pavement Seminar Miami, FL December 6-9, 2010 Outline Outline 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 standards pavement issues and establish standards
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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
*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
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?
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
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