The event was reported to the Air Accidents Investigation Branch (AAIB) at approximately 0736 hrs on 24 May 2013 by Heathrow Airport Operations and an AAIB investigation was commenced immediately. In accordance with the provisions of ICAO Annex 13, France (the state of aircraft design and manufacture) and the United States of America (the state of engine design and manufacture) appointed Accredited Representatives from the BEA and the NTSB , respectively. Technical assistance was also provided by the operator, the aircraft manufacturer (Airbus), the European Aviation Safety Agency (EASA), International Aero Engines (IAE) and UTC Aerospace Systems (UTAS).
During takeoff from Runway 27L at London Heathrow Airport, the fan cowl doors from both engines detached from the aircraft, damaging the airframe and a number of aircraft systems. The flight crew elected to return to Heathrow and on the approach to land on Runway 27R, leaking fuel from a damaged fuel pipe on the right engine ignited and an external fire developed. The left engine continued to operate satisfactorily throughout the flight. The right engine was shut down promptly, reducing the intensity of the fire, and the aircraft landed safely. It was brought to a stop on the runway and the emergency services were quickly in attendance. The fire in the right engine was extinguished and the passengers and crew evacuated via the emergency escape slides on the left side of the aircraft.
The investigation determined that a maintenance error had led to the fan cowl doors on both engines being left unlatched following scheduled overnight maintenance on the aircraft. The unlatched condition of the fan cowl doors was not identified prior to the aircraft’s departure the next morning. A number of organisational factors were contributory to the maintenance error. The operator has since taken action to address these issues.
This, and numerous other similar events, shows that Airbus A320-family aircraft have a history of departing with the fan cowl doors unlatched. It is also evident that, in practice, the flight crew walk-around inspection is not entirely effective in detecting unlatched fan cowl doors and therefore a design solution is necessary. Enhanced methods of detection through design solutions are being considered by the aircraft manufacturer.
As a result of this investigation, five Safety Recommendations were made concerning: fatigue risk management; fan cowl door position warnings; fan cowl door certification requirements; in-flight damage assessments by cabin crew and aircraft evacuation procedures.