What happened
On 2 August 2010, a Boeing 777-236, registration G-YMMI, was parked at Stand 330 at London Heathrow Airport. The aircraft was prepared for a scheduled passenger flight involving 236 passengers and 16 crew members. During the departure preparations, the airbridge was being retracted from the aircraft. As the airbridge auto-leveller moved, it made contact with the nose cowling of the left engine. This impact resulted in a puncture to the outer skin of the cowling, measuring approximately 20 cm in length. Due to the nature of the damage, the aircraft was removed from service.
The investigation
The investigation examined the movements of the airbridge and the visibility available to the operator. It was established that the airbridge controller was not accustomed to the specific type of airbridge used at Stand 330. While the controller used a CCTV monitor to guide the maneuver, the investigation found that the image of the drive axle was small and difficult to discern when the bridge was significantly extended. Furthermore, poor lighting conditions beneath the airbridge hindered the assessment of the equipment's position.
Evidence also indicated that the axle position indicator, which is intended to assist operators in aligning the wheels with parking markings, had been vandalised and was non-functional. This lack of reliable instrumentation meant the controller could not accurately verify the orientation of the axle relative to the aircraft fuselage.