Aircraft Accident Report 2/2007 - Boeing 777-236, G-YMME, 10 June 2004

Formal Report AAR 2/2007. Report on the serious incident to Boeing 777-236, G-YMME, on departure from London Heathrow Airport on 10 June 2004.

From:: Air Accidents Investigation Branch
Published: 10 December 2014

Category:: Commercial - fixed wing
Report type:: Formal report
Date of occurrence:: 10 June 2004
Aircraft type:: Boeing 777-236
Location:: On departure from London Heathrow Airport
Registration:: G-YMME

Summary:

皇冠体育app incident was notified to the Air Accidents Investigation Branch (AAIB) on 11 June 2004. 皇冠体育app AAIB investigation team comprised:

Mr J J Barnett - (Investigator-in-Charge)
Mr K Conradi - (Operations)
Mr S J Hawkins - (Engineering)
Mr C Pollard - (Engineering)
Mr A Foot - (Flight Recorders)

After takeoff from London Heathrow Airport a vapour trail was seen streaming aft of the aircraft. 皇冠体育app flight crew diagnosed that the aircraft was probably leaking fuel from the centre wing fuel tank. 皇冠体育appy declared an emergency and decided to jettison fuel to reduce to maximum landing weight before returning to Heathrow. 皇冠体育appir intention was to minimise heating of the brake units during the landing roll in order to reduce the risk of fire if fuel was to leak onto the wheelbrakes. After landing, the aircraft was met by the Airfield Fire and Rescue Service who reported some vapour emanating from the left landing gear but no apparent fuel leaks.

皇冠体育app fuel leak was caused by fuel escaping through an open purge door inside the left main landing gear bay, on the rear spar of the centre wing tank. 皇冠体育app purge door had been removed during base maintenance at the operator鈥檚 maintenence organisation in Cardiff, between 2 May and 10 May 2004, and had not been refitted prior to the aircraft鈥檚 return to service.

皇冠体育app investigation identified the following causal factors:

1. 皇冠体育app centre wing tank was closed without ensuring that the purge door was in place.
2. When the purge door was removed, defect job cards should have been raised for removal and refitting of the door, but no such cards were raised.
3. 皇冠体育app centre wing tank leak check did not reveal the open purge door because:
1. i. 皇冠体育app purge door was not mentioned within the Aircraft Maintenance Manual (AMM) procedures for purging and leak-checking the centre wing fuel tank.
2. ii. With no record of the purge door removal, the visual inspection for leaks did not include the purge door.
3. iii. 皇冠体育app fuel quantity required to leak check the purge door was incorrectly stated in the AMM.
4. Awareness of the existence of a purge door on the Boeing 777 was low among the production staff working on G-YMME, due in part to an absence of cross references within the AMM.

Following the incident, significant safety action was taken by both the maintenance organisation and the aircraft manufacturer to address issues discovered during the investigation. 皇冠体育app AAIB made five Safety Recommendations.

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