Aircraft Accident Report 3/2005 - Boeing 757-236, G-CPER, 7 September 2003

Formal Report AAR 3/2005. Report on the serious incident to Boeing 757-236, G-CPER on 7 September 2003.


The incident was notified to the Air Accidents Investigation Branch (AAIB) at 2045 hrs on 7 September 2003. The investigation, which began early the following morning, was conducted by:

Mr D S Miller (Investigator in Charge
Mr R G Ross (Engineering)
Mr P Hannant (Operations)
Mr A Foot (Flight Recorders)

The incident to the Boeing 757 aircraft occurred on the first flight following a 26-day major maintenance check. Shortly after takeoff on a scheduled passenger flight from London Heathrow to Paris, a hot oil smell, that had been present in the cockpit on engine startup, returned. The flight crew donned oxygen masks and immediately diverted to London Gatwick Airport. During the autopilot-coupled ILS approach to Gatwick, the aircraft drifted to the right of the localiser after selection of Flap 30. When the autopilot was disconnected, a large amount of manual left roll control was needed to prevent the aircraft from turning to the right. It was necessary to maintain this control input until touch down. The aircraft landed safely despite these difficulties, with no injuries to any of the passengers or crew.

The investigation determined that the incident had been caused by maintenance errors that had culminated in the failure to reinstall two access panels, 666AR and 666BR, on the right-hand outboard flap and incorrect procedures being used to service the engine oils. The events were the result of a combination of errors on the part of the individuals involved and systemic issues, that had greatly increased the probability of such errors being committed.

The following immediate causal factors were identified:

  1. The tasks of refitting the panels to the right wing and correctly certifying for the work carried out were not performed to the required airworthiness standard

  2. Ineffective supervision of maintenance staff had allowed working practices to develop that had compromised the level of airworthiness control and had become accepted as the ‘norm’.

  3. There was a culture, both on the ramp and in the maintenance hangar, which was not effective in ensuring that maintenance staff operated within the scope of their company authorisation and in accordance with approved instructions.

  4. The maintenance planning and task instructions, relating to oil servicing on the Boeing 757 fleet, were inappropriate and did not ensure compliance with the approved instructions.

  5. The Airline’s Quality Assurance Programme was not effective in highlighting these unsatisfactory maintenance practices.

Eight safety recommendations are made in this report, with the intention of preventing similar incidents in the future.

Download full report:

Pub Version G-CPER.pdf (4,482.95 kb)

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Summary: AAR 2/2005 - Boeing 757-236, G-CPER

Published 10 December 2014