Incident Overview
On August 2, 2010, at approximately 2110 UTC, a Boeing 777-236 (registration G-YMMI) was parked at Stand 330 of London Heathrow Airport, ready to depart on a commercial passenger flight to Singapore. As the airbridge operator moved the bridge away from the aircraft, the auto-leveller mechanism contacted the left engine nose cowling, puncturing the outer skin over a length of approximately 20 cm. The damage rendered the aircraft unserviceable.
There were 16 crew members and 236 passengers on board, none of whom reported any injuries.
Airbridge Operator Actions
The operator reported moving the airbridge slowly backward while adjusting its alignment relative to the fuselage. She relied on a CCTV monitor at the driving position to confirm that the airbridge wheels were aligned with guide lines on the apron. However, as she continued to withdraw the bridge, the collision occurred.
Contributing Factors from the Source
According to the airport operator, the axle position indicator in the airbridge driving position had been vandalized and was unusable. Airline managers at the scene noted that the CCTV image of the wheel axle orientation was poor, and lighting under the airbridge was inadequate. The airline's report indicated that training for airbridge operators emphasizes visual checking of axle orientation and maintaining a lookout, with CCTV and axle indicators as support tools. The report concluded that the axle was most likely not parallel to the aircraft when the operator, who was unfamiliar with Stand 330, began withdrawing the bridge.
Previous Incident at the Same Stand
In June 2002, the AAIB investigated a similar incident at Stand 330, during which an airbridge punctured the pressure hull of a parked aircraft (see AAIB Bulletin 5/2003). The investigation found that the airbridge controller had difficulty assessing the orientation of the driving axle, partly because the CCTV camera was mounted approximately 25 m from the wheels when the bridge was extended. The controller was also unfamiliar with the type of airbridge at that stand. Safety Recommendation 2003-23 was issued, urging Heathrow Airport Limited to improve the ease and accuracy of assessing drive axle orientation for that airbridge model. The recommendation was accepted, and an axle position indicator was subsequently installed.
Post-Incident Actions
Following this incident, the airport operator agreed to conduct a trial to limit the turning ability and speed of airbridges at Stands 330–336, and to undertake a comprehensive review of all airbridges at the airport.