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Recommendation issued to: Australian Operators of B737-800 series aircraft

Recommendation details
Output No: R20040093
Date issued: 23 December 2004
Safety action status:
Background:

Since October 2004, there has been a series of Boeing 737 main landing gear tyre failures as detailed in Table 1 below.

Of particular concern with the above failures are those associated with the 737-800 series aircraft.

Those failures involved:

* new generation high gross weight wheel tyres introduced into service approximately two and a half years ago
* tyres on either the fourth - R4 (one occurrence) or fifth - R5 (five occurrences) retread.

Retreading of aircraft tyres has been a proven practice for many years, and although failures have occurred from time to time, they are not a common event, with only four failures involving Boeing 737 aircraft reported to the ATSB during the period between January 2003 and October 2004. As such, the number of occurrences reported to the ATSB since 13 October 2004 represents a significant increase in occurrences of this type.

The investigation of these tyre failures is continuing and is yet to determine the nature and mode of the failures, including any aspects relating to tyre manufacture, retreading, maintenance and operational considerations.

Table 1: Summary of Boeing 737 tyre failures since October 2004
Date Aircraft Location Model Summary 13 Oct VH-VOJ Brisbane Qld 737-81Q The aircraft landed with a deflated right inboard main tyre. The tyre is thought to have deflated during the take-off run from Perth.
2 Dec VH-VOV Sydney NSW 737-82R During the take-off run from runway 01, damage occurred to one of the aircraft's main tyres and tyre tread debris was found on the runway. After landing in Sydney, the crew noticed that the right landing gear door had been damaged when the tyre tread separated.
3 Dec VH-VXF Perth WA 737-838 Severely damaged tread found on main landing gear tyre during post flight maintenance. 4 Dec VH-VOH Sydney NSW 737-86N While the aircraft was taxiing for departure the crew heard and felt an unusual bump through the airframe. Shortly afterwards the Surface Movement Controller advised that the aircraft appeared to have a deflated main landing gear tyre. After inspection by ground personnel it was decided to taxi back to the terminal building, but during this manoeuvre the tyre began to shred. The aircraft was stopped on the taxiway and the passengers were disembarked for transport back to the terminal. Engineering staff replaced the both left main landing gear wheel assemblies and the aircraft was towed back to the parking area.
15 Dec VH-TJP Perth WA 737-476 The crew reported airframe vibration after the aircraft took off from Perth and a subsequent runway inspection revealed rubber detritus in the vicinity of the rotation point. The crew notified ATC and continued the flight to Adelaide where the airport emergency services were placed on standby. The aircraft landed without further incident and the left main landing gear outer tyre was found damaged and deflated.
19 Dec VH-VOH Canberra ACT 737-86N During the landing, a main landing gear tyre blew, causing damage to the right landing gear doors, the right wing flaps and a hydraulic line in the landing gear bay.

The ATSB investigation is continuing.
20 Dec VH-VOR Sydney NSW 737-8FE After landing at Sydney, ground engineers noticed sidewall separation and shredding of the tyre shoulders on the left inboard main landing gear tyre.

Output text

Safety Recommendation

In light of the recent industry experience, the Australian Transport Safety Bureau recommends that Australian operators of Boeing 737-800 series aircraft review the practice of fitting retread tyres of R4 (fourth retread) or above, until their serviceability limitations can be identified.

Initial response
Date issued: 15 February 2005
Response from: Australian Operators of B737-800 series aircraft
Action status: Closed - Accepted
Response text:

On 23 December 2004 Qantas Airways Limited provided the following response to recommendation R20040093

  1. On 22 December 2004, a visual check of all QANTAS B737-800 aircraft main gear tyres was commenced. No tyres were reported as faulty as a result of that visual inspection for damage.
  2. The inspection will be amended on 23 December 2004 to inspect the tyres more carefully on maintenance lay-overs and the pilots advised to scrutinise the main gear tyres during their pre flight inspections (needed at stations where transits are carried out without engineering involvement).
  3. QANTAS maintenance practices on B737-800 aircraft require tyre pressure 'top ups' to be annotated in the aircraft Technical Log. Tyres requiring frequent 'top up' can be readily identified and action taken (progressive tyre deflation and repeated 'top up' is a good indicator of incipient tyre failure).
  4. QANTAS require B737-800 tyres to be inflated to 208 psi after wheel assembly and left for 12 hours. The allowable pressure drop after 12 hours is +/- 5 psi. This practice increases the chance of detecting a faulty tyre liner.

On 21 February 2005, Virgin Blue Airlines advised the ATSB that, 'In response to the subject Safety Recommendation, Virgin Blue Airlines Head of Engineering directed that the maximum retread level of all B737-800 main wheel tyres used in service would be the R3 level. This level conforms to the Safety Recommendation.'

 
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Last update 01 April 2011