CUSTOMER SERVICES DIRECTORATE AIRBUS 1 ROND POINT...

CUSTOMER SERVICES DIRECTORATE AIRBUS 1 ROND POINT MAURICE BELLONTE 31707 BLAGNAC CEDEX FRANCE TELEPHONE + 33 (0)5 61 93 33 33

TELEX AIRBU 530526F SERVICE INFORMATION LETTER

SIL NUMBER: 32-121 PAGE: 1 of 19

SUBJECT: TIRES INSPECTION – IN-SERVICE REMOVAL CRITERIA ATA CHAPTER: 32-41-00 AIRCRAFT TYPE: A300, A310, A300-600,

A318, A319, A320, A321 A330-200, A330-300, A340-200, A340-300, A340-500, A340-600 A380-800

APPLICABILITY: ALL REFERENCES: Bridgestone: Tire Specification & Maintenance Manual

Goodyear: The Comprehensive Guide to Aircraft Tire Care and Maintenance Michelin: Aircraft Tire Care & Service Manual

1. PURPOSE

The purpose of the revision is to clarify the wording of the notes dealing with the return to the base when tire has reached a criteria for removal. On a same aircraft it is possible to find tires from different manufacturers. In order to make easier the reading of removal criteria, it has been decided to try to harmonize these data to the best extent and to have criteria related to the tire size/type instead of the manufacturer. This document is a compilation of data issued from manufacturers documentation and also from in-service experience.

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Note: It is to be highlighted that in some countries, the limits given in this document may have to

be agreed by local airworthiness authorities as they can have some specific requirements.

DATE: Oct.23/2007 REVISION: 01, Sep 08/2009

AIRBUS

SERVICE INFORMATION LETTER


2. BACKGROUND

The information concerning the criteria for inspection of tires that are contained in the current issue of the Aircraft Maintenance Manual for each Airbus aircraft type is directly taken from the various manuals issued by the tires manufacturers. This has been the Airbus policy for many years, in fact since the first A300 aircraft entry into service. However, on a same aircraft it is possible to find mixed configurations, i.e tires of same size but from different manufacturers also. Therefore, it has been decided to try to harmonize these data and to have criteria related to the tire size/type instead of the manufacturer.

3. DESCRIPTION

This Service Information Letter is a compilation of data issued from manufacturers documentation and also from in-service experience.

4. AIRBUS ACTION

The criteria for tire removal are given in the following chapters: • Tread pattern:

o Normal wear o Uneven wear (shoulder, center)

• Tread damage: o Flat spots o Tread rubber reversion o Peeled rib o Thrown tread o Tread cuts o Chevron cutting o Groove cracking o Rib undercutting o Open tread-splice o Tread chipping and chunking

• Sidewalls o Cuts

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o Weathering and cracking • Blisters, bulges • Miscellaneous

o Tire contamination o Maximum speed of utilization


AIRBUS



4.1 Tread wear pattern : (see Figure 1) 4.1.1 Normal wear: An even tread wear indicates that the tire has been properly maintained during its service life.

At the main base (or maintenance base), the tire shall be removed from aircraft if:

• the tread wear level reaches the bottom of any groove at any point of the tread surface, or

• the reinforced ply (bias tire) or the protector ply (radial tire) is exposed at any point of the tread surface.

NOTE

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TIRES HAVING REACHED THE ABOVE LIMITS SHOULD BE REPLACED IMMEDIATELY. A SINGLE RETURN TO BASE (*) FLIGHT IS PERMITTED IF THE AIRCRAFT IS IN OUTSIDE STATION. (*) Any station where a spare wheel is available.


AIRBUS



4.1.2 Uneven wear: In general, under inflation will lead to excessive tread shoulder wear and subsequent heat build-up which may result in severe internal tire damage.

Over inflation accelerates the center tread wear, reduces tire traction, reduces the number of cycles and make the tire more susceptible to cutting and foreign object damage (FOD)

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At the main base (or maintenance base), the tire shall be removed from the aircraft if the wear limits are reached.

NOTE

TIRES HAVING REACHED THE ABOVE LIMITS SHOULD BE REPLACED IMMEDIATELY. A SINGLE RETURN TO BASE (*) FLIGHT IS PERMITTED IF THE AIRCRAFT IS IN OUTSIDE STATION. (*) Any station where a spare wheel is available.

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AIRBUS



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Figure 1: Tire wear and deterioration characteristics


AIRBUS



4.2 Tread damage: 4.2.1 Flat spots: Flat spot may result from locking of the wheel during braking, hard touchdown or severe steering manoeuvre (for the nose tires).

The tire shall be removed from aircraft if the flat spot reaches the reinforcing ply (bias tire) or the protector ply (radial tire).

NOTE

IF THE FLAT SPOT DOES NOT REACH THE ABOVE-MENTIONED LIMIT, IF THERE IS SUFFICIENT GROOVE DEPTH IN THE WHOLE FLAT SPOT AREA, IF THERE IS NO INCIPIENT SEPARATION AND IF VIBRATION IS NOT DETECTED DURING ROLLING, THE TIRE CAN REMAIN IN SERVICE. 4.2.2 Tread rubber reversion:

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Tread rubber reversion is generally caused by wheel locking on wet or ice covered runways. The affected area is similar in shape to a flat spot (oval), but the rubber appears to be melted.


Administrator高亮

AIRBUS



The tire shall be removed from aircraft if:

o the reinforcing ply (bias tire) or the protector ply (radial tire) is reached, o or shimmy or unbalance problem are experienced

4.2.3 Peeled rib: Usually starts with a cut in the tread and results in a circumferential delamination of the tread rib away from the tire carcass.

Remove the tire from aircraft

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4.2.4 Thrown tread:


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AIRBUS



Partial or complete loss of tread down to the carcass.

Tire must be removed immediately from service. Note: Pieces from the tread must be requested from airport authorities and returned to the home

base for potential analysis by the vendor. If the tire is still inflated after aircraft is at parking position, record the pressure after it has cooled down (allow 3 hours). Then deflate the tire before removing the wheel assembly. Caution: Avoid approaching wheel from either side of the tire. Always go near the wheels from

an oblique angle - direction of the tire’s shoulders. Warning: Remove the valve core when the tire is fully deflated.

Removal of the wheel valve core on an inflated tire could project the core with high velocity and force. This can cause injury to persons.

Early signs of tread separation can manifest themselves in the form of tread bulges, local uneven wear (depression) or local tread/sidewall rubber split.

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4.2.5 Tread cuts: Foreign objects that are present on the runway, taxiway and parking areas cause cuts to the tires.

The definition of cut limits is complex. It is based on the service experience of each vendor and is not easy to harmonize. Due to different technologies and tire constructions, tolerance to damages can be different for each manufacturer and even each tire reference for a same manufacturer. Refer to the relevant vendor’s manual for details. In the absence of specific cut limits in documentation, the tire shall be removed from the aircraft if:

• cut or embedded object exposes or penetrates the reinforcing ply (bias tire) or the protector ply (radial tire): o Cut penetrates the outer casing ply (bias tire) or the outer layer (radial tire).

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o Cut length is greater than 50 mm (2 in) or o Cut width is greater than 3 mm (0.118 in) or o Cut is not contained within one rib. o Cut is contained within one rib but the ends of the cut are more than 13 mm

(0.5 in) apart when measured in the radial direction.

• cut or embedded object does not expose or does not penetrate the reinforcing ply (bias tire) or the protector ply (radial tire):


AIRBUS



o cut length is greater than 300 mm (12 in) or o cut width is greater than 3 mm (0.118 in) or o Cut is not contained within one rib. o Cut is contained within one rib but the ends of the cut are more than 13 mm

(0.5 in) apart when measured in radial direction.

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4.2.6 Chevron cutting Tread damage (small z-, s- or v-shaped cracks) caused by running and / or braking on cross-grooved runways.

Due to different technologies and tire constructions, tolerance to damages can be different for each manufacturer and even each tire reference for a same manufacturer. Refer to the relevant vendor’s manual for details. In the absence of specific cut limits in documentation, the tire shall be removed from the aircraft if:

• tread cut criteria are reached, or • the tread reinforcing ply (bias tire) or the protector ply (radial tire) is exposed.

4.2.7 Groove cracking Groove cracking may result from environmental aggression of the rubber (ozone attack for example) or from an excessive mechanical solicitation of the tire. These cracks occur at the bottom of the tread groove.

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The tire shall be removed from the aircraft if:

• the groove cracking exposes the reinforcing ply (bias tire) or the protector ply (radial tire).

• the groove cracking is undercutting the adjacent rib. 4.2.8 Rib undercutting This is an extension of groove cracking resulting from mechanical solicitation and progressing under a tread rib. It can lead to tread chunking, peeled rib or thrown tread.

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The tire shall be removed from aircraft as soon as the crack extends under the rib. 4.2.9 Open tread splice This is a crack in the rubber where tread joint or splice separates.

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A tire having this defect must be removed from the aircraft. 4.2.10 Tread chipping and chunking:


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AIRBUS



This is a condition visible at the edge of the tread rib in which small amounts of rubber begins to separate from the tread surface. Tread chunking can be caused by high lateral loading of the tire, sometimes caused by tight turning.

The tire shall be removed from the aircraft if fabric is exposed.

4.3 Sidewalls:

4.3.1 Cuts or cracks on the sidewall: Sidewall cuts are often caused by foreign objects present on the operating surfaces.

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The tire shall be removed from the aircraft if sidewall cords are exposed or damaged. Cuts or cracks in the rubber that do not reach the cord plies are not detrimental to tire performance. The tire can remain in service. 4.3.2 Weathering and radial cracking: Weathering and cracking occur when tires are exposed to aggressive environmental conditions.

The tire shall be removed from the aircraft if sidewall cords are exposed.

4.4 Blisters and bulges They normally indicate a separation of components.

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The tire shall be removed from the aircraft immediately. Mark the affected area before deflating the tire for easy identification and analysis by the vendor.

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5. Miscellaneous: 5.1 Tires contamination (hydraulic fluid, fuel, …)

In case of contamination, check for rubber condition. The tire has to be cleaned quickly with denatured alcohol to remove the contaminant then washed with a soap and water solution. Caution: If the rubber feels soft or spongy when probed or bulges are present, then tire is no

more suitable for service. The wheel assembly shall be removed from aircraft.

4.5 Maximum speed of utilization On A300 B2, the speed is limited to 210 mph (338 km/h). On other A300 aircraft (B4, -600), A310, A318, A319, A320 and A321 it is limited to 225 mph (362 km/h / 195.5 kt). Note: This limitation is valid even for tires marked 235 mph (378km/h / 204 kt) or 245 mph (394

km/h / 213 kt). On A330, A340 (including A340-500 and A340-600) and A380 aircraft, the maximum take-off speed is 235 mph (378 km/h / 204 kt). In case of over speed take-off or landing, all the wheels have to be removed from the aircraft. The event must be made known when the casing is returned to the tire manufacturer.

CAUTION: THERE IS NO TOLERANCE.

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6. INFORMATION:


AIRBUS


SIL NUMBER: 32-121 PAGE: 19 of 19 DATE: Oct.23/2007 REVISION: 01, Sep 08/2009

After the information contained in this document is incorporated in the relevant AMM, the SIL will be cancelled.

© AIRBUS S.A.S. 2008. All rights reserved. Confidential and proprietary document. This document and all information contained herein is the sole property of AIRBUS S.A.S.. No intellectual property rights are granted by the delivery of this document or the disclosure of itscontent. This document shall not be reproduced or disclosed to a third party without the expresswritten consent of AIRBUS S.A.S.. This document and its content shall not be used for any purpose other than that for which it is supplied.

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