HIGH TIRE PRESSURE TESTS - alacpa.orgalacpa.org/index_archivos/dia4_htpt mia 2010 december.pdf · Survey Observations •All 6 airports reporting rutting had both narrow body and

ALACPA Seminar �

Presented by

Cyril FABREyHead Of Airfield PavementAirport Operations

HIGH TIRE PRESSURE TESTS & W ld id Ai t S& Worldwide Airport Survey

HTPT ALACPA SEMINAR - Dec.2010

Summary

•Background

•ACI Airport Survey•ACI Airport Survey

•Full-Scale Tests

prie

tary

doc

umen

t.

C l i d d ti

rese

rved

. Con

fiden

tial a

nd p

ro •Conclusions and recommendations

© A

IRB

US

S.A

.S.

All

right

s


Current regulations on tire pressure limitations

• The current ACN / PCN procedure specified in the ICAO Annex 14,“Aerodromes”, contains four maximum allowable tire pressure categories

hi h d i th ti f t t th f i twhich are used in the reporting of pavement strength for an airport:

W = No pressure limitation - HighX = 1.5 MPa (218 psi) limitation - MediumX 1.5 MPa (218 psi) limitation MediumY = 1.0 MPa (145 psi) limitation - LowZ = 0.5 MPa (73 psi) limitation. – Very low

• Tire pressure categories were established in early 1980’s.

Scientific rationale was not fully robust

Origin of tire pressure limitations were not clearly established

prie

tary

doc

umen

t.

Origin of tire pressure limitations were not clearly established

• Airport PCN ratings should reflect current pavement capability and aircrafttraffic

rese

rved

. Con

fiden

tial a

nd p

ro

• A340-500/-600, B747-400ER, B777-300ER and new B787, A350 XWBand B747-8 all exceed category X upper limit

© A

IRB

US

S.A

.S.

All

right

s


Aircraft Tire Pressure summary

Aircraft design optimization is the best compromise between actual technology capabilities and airline demand in terms of aircraft payload & range capabilities.

prie

tary

doc

umen

t.re

serv

ed. C

onfid

entia

l and

pro

© A

IRB

US

S.A

.S.

All

right

s


Airport Compatibility – Tire Pressure Rating

Tire pressure Cat. repartition for LR aircraft operations

131

274 41 % 59%

193

prie

tary

doc

umen

t.re

serv

ed. C

onfid

entia

l and

pro

Current LR Airport Runways -598 Total

Current LR aircraft traffic on RWY PCN-Type - 467 Total

© A

IRB

US

S.A

.S.

All

right

s

�HTPT ALACPA SEMINAR - Dec.2010

Proposed change to ICAO tire pressure categories

Proposed New ICAOTire Pressure

CategoryCurrent ICAO Limits

MPa (psi), loaded*

Proposed New ICAO Limits

MP ( i) l d dg y

MPa (psi), loaded

W High Unlimited

XMedium: 1.50

(218)High: 1.75 (254)

prie

tary

doc

umen

t.

(218)

Y Low: 1.0 (145)Medium: 1.25

(181)

rese

rved

. Con

fiden

tial a

nd p

ro

( )(181)

Z Very Low: .50 (73) Low: .50 (73)

© A

IRB

US

S.A

.S.

All

right

s


* Loaded pressure = unloaded pressure x 1.04

Why do aircraft tire pressures tend to increase ?

Payload Fuel Burn reduction

Drag reduction

Range

Drag reduction

Noise reduction in approach

Less emissions

MTOW IncreaseMTOW Increase

Fuselage length increase

Wing-span increase (& shape) for drag reductionHigher wheel load

prie

tary

doc

umen

t.

Fewer wheels for:

Weight saving, noise & drag reduction (approach)

Higher wheel load

&

Tire pressure

rese

rved

. Con

fiden

tial a

nd p

ro (approach)

Better maneuverability

but, larger wheels and tires (higher load biliti

Tire pressure

© A

IRB

US

S.A

.S.

All

right

s


capabilities

higher braking capabilities)

How to address the tire pressure concern?

We used a Two-pronged approach:

•Airport survey

Airport Council International: Questionnaire sent to airportsAirport Council International: Questionnaire sent to airportsworldwide

•Perform full-scale tests by considering mainparameters which are expected to influence tire

prie

tary

doc

umen

t.

pressure effect on asphalt concrete base &surface course

rese

rved

. Con

fiden

tial a

nd p

ro

AIRBUS / French DGAC HTPT, Blagnac – France

BOEING / FAA HTPT, NAPTF, Atlantic-City, NJ, USA

© A

IRB

US

S.A

.S.

All

right

s

, , y, ,


ACI AIRPORT SURVEYACI AIRPORT SURVEY

prie

tary

doc

umen

t.re

serv

ed. C

onfid

entia

l and

pro

© A

IRB

US

S.A

.S.

All

right

s


ACI Worldwide Survey

• Objective: To determine if high tire pressures arecausing increased levels of pavement distress atg pairports worldwide.

The Worldwide survey was launched in 2009.

• Primary failures directly attributable to high tire pressurewould be rutting (directly in wheel path) and / or possiblytop down cracking.

• Of 32 airports responding, only 6 reported ruttingi Oth di t t d li li

prie

tary

doc

umen

t.

issues. Other distresses reported were raveling, slippage,poor drainage or other non-load and non-pressure relatedproblems

rese

rved

. Con

fiden

tial a

nd p

ro problems.

• The survey was re-released in early 2010 to attempt to getmore responses. (Only one additional survey was

© A

IRB

US

S.A

.S.

All

right

s more responses. (Only one additional survey wasreceived.)


Survey Observations

• All 6 airports reporting rutting had both narrow body andwide body traffic which were the source of the problem.

The tire pressures of the narrow body aircraft are less thanthe current X limit of 1.5 MPa (218 psi).

• The areas of distress are primarily in the taxiway hold andapron areas, and areas where heavy braking or turningoccursoccurs.

These are known problem areas for all airports, and cannotbe directly attributed to high tire pressures

prie

tary

doc

umen

t.

be directly attributed to high tire pressures.

• There is concern over high pavement temperatures, andrightly so, which may relate to higher rutting levels. Slow

rese

rved

. Con

fiden

tial a

nd p

ro

rightly so, which may relate to higher rutting levels. Slowmoving loads also produce more strain and deformation thanfast moving traffic (Ref: FAA report “Asphalt Concrete Strain

© A

IRB

US

S.A

.S.

All

right

s

Responses at High Loads and Low Speeds at the NAPTF”).


Summary of the ACI airport survey

• Survey results indicated that most pavement distresses arelocalized to areas of slow moving traffic such as runway

d d t i h ld d d bends, aprons and taxiway hold areas - and are caused byboth dual wheel and wide body aircraft.

• The solution in many cases has been the use of a stifferbinder indicating a materials issue, not a pavement designiissue.

• Materials testing should confirm that current asphalt

prie

tary

doc

umen

t.

• Materials testing should confirm that current asphalttechnology is capable of handling higher tire pressures.

rese

rved

. Con

fiden

tial a

nd p

ro

• Full scale tests should determine if damage induced byproposed new tire pressure limit of 1.75 MPa (254 psi) is anyworse than the current 1 5 MPa (218 psi) limit

© A

IRB

US

S.A

.S.

All

right

s worse than the current 1.5 MPa (218 psi) limit.


FULL SCALE TESTSFULL-SCALE TESTS

prie

tary

doc

umen

t.re

serv

ed. C

onfid

entia

l and

pro

© A

IRB

US

S.A

.S.

All

right

s


Tests and Objectives

• Two full-scale tests, representative of actual in-service airfield pavement andconditions

DGAC / Ai b HTPT Bl FDGAC / Airbus HTPT , Blagnac – France

FAA / Boeing HTPT, NAPTF, Atlantic-City, NJ, USA

• Common objectives:

Compare and understand the rutting behavior of a representative selectionof pavements subject to the circulation of wheels with a range of loads andtire pressures, while isolating as much as possible tire pressure effect fromp , g p pwheel-load effect and other external factors.

Determine whether the new proposed tire pressure limit for code letter X(1.75 MPa – 254 psi) was a reasonable upper limit for typical pavements

prie

tary

doc

umen

t.

( p ) pp yp p

• Tested tire pressures : 1.5 MPa (218 psi) vs. 1.75 MPa (254 psi)

• Range of wheel-loads: 23.8t (52,500 lb) to 33.2t (66,400 lb)

rese

rved

. Con

fiden

tial a

nd p

ro • Representative range of pavement characteristics regarding:

Rutting performance

Thickness

© A

IRB

US

S.A

.S.

All

right

s

Surface treatment (grooving)


DGAC / Airbus HTPT - Experimental RWY -Longitudinal Cross section

Structure A0.06m SAC 10.20m BAC

Structure B0.08m SAC 10.18m BAC

Structure C0.12m SAC 1

0.14m BAC

Structure D0.08m SAC 20.18m BAC

Structure E0.08m SAC 10.18m BAC

Structure F0.08m SAC 1 gr.

0.18m BAC

Structure G0.08m SAC 30.18m BAC

HTPT Phase – 1/0.40m UGA/0.70m foundation

prie

tary

doc

umen

t.

• 4 dual-wheel modules, each with a combination of loads and tire pressures

(similar to current and future aircraft)Tire Pressure: 1.5 MPa (218 psi) to 1.75 MPa (254 psi)

rese

rved

. Con

fiden

tial a

nd p

ro

( p ) ( p )Wheel-load: 28.7t (57,400 lb) to 33.2t (66,400 lb)

• Traffic speed ≈ 4 km/h (3.6 ft/s)• Surface asphalt temperature up to 60°C

© A

IRB

US

S.A

.S.

All

right

s


p p p• 11,000 load applications from October 2009 to August 2010

DGAC / Airbus test results after 11,000 loadings

Module Module Module Module Pressure effect Wheel-load effect

Section M1 M2 M3 M4M1 vs

M4@28 7t

Load increase

effect

M3 vs M2

@33 2t

M2 vs [email protected]

M3 vs [email protected]

@28.7t effect @33.2t

(mm) (mm) (mm) (mm)(∆ in mm)

(∆ in mm)

(∆ in mm)

(∆ in mm)

(∆ in mm)) ) ) ) )

A 24.9 22.9 27.9 21.8 3.1 +1.9 5.0 1.1 3.0B - E 22.9 22.4 27.5 20.7 2.2 +2.9 5.1 1.7 4.6

C 24 2 22 6 25 4 21 8 2 4 +0 4 2 8 0 8 1 2

prie

tary

doc

umen

t.

C 24.2 22.6 25.4 21.8 2.4 +0.4 2.8 0.8 1.2D 20.9 20.2 21.9 17.5 3.5 -1.8 1.7 2.7 1.0F 19.7 21.1 22.6 17.8 1.9 -0.4 1.5 3.3 2.9

G at

rese

rved

. Con

fiden

tial a

nd p

ro G at 11,000 passes

23.2 22.0 26.9 20.9 2.3 +2.6 4.9 1.1 3.7

Section A had the thinnest asphalt layer (6cm) C the thickest surface asphalt layer (12cm) and Sections B D

© A

IRB

US

S.A

.S.

All

right

s


Section A had the thinnest asphalt layer (6cm), C the thickest surface asphalt layer (12cm) and Sections B, D, E, F and G had the reference AC surface thickness (8cm)

DGAC / Airbus test results after 11,000 loadings

• Total rut depth greater than 20-25 mm (0.79-0.98 in)

• No pavement structural failures

• Rut depth differences between 1.5 MPa (218 psi) and 1.75 MPa (254 psi), at constant wheel-load, range:

from 1 9 mm (0 07 in) to 3 5 mm (0 14 in) for 28 7t wheel loadfrom 1.9 mm (0.07 in) to 3.5 mm (0.14 in) for 28.7t wheel-load

from 1.5 mm (0.06 in) to 5.1 mm (0.20 in) for 33.2t wheel-load

• Rut depth differences for two different wheel-loads, allowed to isolate p ,the wheel-load effect within the previous results. The wheel-load effect represented from 0.4 mm (0.02 in) to 2.9 mm (0.11 in).

The contribution of tire pressure to rutting is very low

prie

tary

doc

umen

t.

The contribution of tire pressure to rutting is very low

• Pavement temperature is the most important parameter regarding rutting initiation

rese

rved

. Con

fiden

tial a

nd p

ro

• Thickness was revealed to be an insignificant factor.

• Modified AC (high performance toward rutting) and grooved sections perform better than other sections

© A

IRB

US

S.A

.S.

All

right

s perform better than other sections.


FAA / Boeing HTPT Trafficking

• Dual-wheel module with 1.50 MPa (218 psi) in one tire and 1 75 MPa (254 psi) in the other tire1.75 MPa (254 psi) in the other tire.

• Traffic speed = 1.1 km/h (1 ft/s)

• Wheel loads 23.8t (52,500 lb) and 27.8t (61,300 lb)( ) ( )

• Asphalt temperatures were between 36 and 46 °C

prie

tary

doc

umen

t.re

serv

ed. C

onfid

entia

l and

pro

© A

IRB

US

S.A

.S.

All

right

s


FAA / Boeing test results

• Tire pressure had an insignificant effect on rut depth, with the observed differencebetween 1.75 and 1.5 MPa loading being in the range 0 to 9 %.

• The rutting in the unheated sections was significantly less than in the heated sections (~1.25

Heated Area Rut Depth Changes

g g y (cm), and the rutting performance with respect to tire pressure was consistent with the resultsfrom the heated sections.

1.8

2

PG64-22_61.3K_254psi PG64-22_61.3K_218 psi PG64-22_52.5K_254 psi PG64-22_52.5K_218 psi

PG76-22_61.3K_254 psi PG76-22_61.3K_218psi PG76-22_52.5K_254 psi PG76-22_52.5K_218 psi

1.2

1.4

1.6

hea

val), in

ch

prie

tary

doc

umen

t.

0.6

0.8

1

ax R

ut D

epth

(w

Uph

rese

rved

. Con

fiden

tial a

nd p

ro

0

0.2

0.4

Ma

© A

IRB

US

S.A

.S.

All

right

s


0 200 400 600 800 1000 1200

Pass Number

Conclusions of DGAC-Airbus & FAA-Boeing tests

• Test results indicate that rutting can be significantly reduced byusing improved asphalt binders.

• Rut depth variation increases simultaneously with temperatureindependent of tire pressureindependent of tire pressure.

• Wheel-load effect is insignificant on surface and base asphaltconcrete, but more confined to the unbound material, therefore, morerelated to the structural behavior of airfield pavement, which is alreadyconsidered in the ACN and the pavement thickness design method.

prie

tary

doc

umen

t.

p g

• Both tests results clearly indicate that the tire pressure effectlti f i f 1 5 MP (218 i) t 1 75 MP (254

rese

rved

. Con

fiden

tial a

nd p

ro resulting from an increase from 1.5 MPa (218 psi) to 1.75 MPa (254psi) will not affect adversely surface or base asphalt concretelayers, nor the structural capacity and life duration of typical

© A

IRB

US

S.A

.S.

All

right

s

airfield pavement structures.


CONCLUSIONSCONCLUSIONS

andand

RECOMMENDATIONS

prie

tary

doc

umen

t. RECOMMENDATIONS

rese

rved

. Con

fiden

tial a

nd p

ro©

AIR

BU

S S

.A.S

. A

ll rig

hts


Conclusions and Recommandations

• Both the ACI airport survey and the full-scale tests demonstrate that theproposed change of tire pressure limitations can be ratified withoutputting aircraft or airfield pavement at riskputting aircraft or airfield pavement at risk.

• They allow the ICAO tire pressure limit codes to be formally andpermanently changed to be more consistent with both the performanceof real world pavement and new generation aircraft.

Tire Pressure Current ICAO Limits Proposed New ICAOTire Pressure Category

Current ICAO Limits

MPa (PSI), loadedProposed New ICAO

Limits MPa (PSI), loaded

W High Unlimited

prie

tary

doc

umen

t.

W High Unlimited

X Medium: 1.50 (218) High: 1.75 (254)

rese

rved

. Con

fiden

tial a

nd p

ro

Y Low: 1.0 (145) Medium: 1.25 (181)

Z V L 50 (73) L 50 (73)

© A

IRB

US

S.A

.S.

All

right

s


Z Very Low: .50 (73) Low: .50 (73)

© AIRBUS S.A.S. All rights reserved. Confidential andproprietary document.

This document and all information contained herein is the soleproperty of AIRBUS S.A.S.. No intellectual property rights aregranted by the delivery of this document or the disclosure ofits content. This document shall not be reproduced ordisclosed to a third party without the express written consentof AIRBUS S.A.S. This document and its content shall not beused for any purpose other than that for which it is supplied.

The statements made herein do not constitute an offer. Theyare based on the mentioned assumptions and are expressedin good faith. Where the supporting grounds for thesestatements are not shown, AIRBUS S.A.S. will be pleased toexplain the basis thereofexplain the basis thereof.

AIRBUS, its logo, A300, A310, A318, A319, A320, A321,A330, A340, A350, A380, A400M are registered trademarks.

prie

tary

doc

umen

t.re

serv

ed. C

onfid

entia

l and

pro

© A

IRB

US

S.A

.S.

All

right

s


Documents

HIGH TIRE PRESSURE TESTS - alacpa.orgalacpa.org/index_archivos/dia4_htpt mia 2010 december.pdf · Survey Observations •All 6 airports reporting rutting had both narrow body and