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!