What happened
On 31 May 2006, a Boeing 737-600, registration 7T-VJT, arrived at London Gatwick Airport following a flight from Algiers. After vacating the runway, the crew was instructed to taxi to a newly assigned stand. During the taxiing process, the commander misidentified the visual docking guidance signals. While attempting to find a clear indication to stop, the aircraft continued past its intended position, overrunning the correct stopping point by 10.3 metres.
As the aircraft entered the stand area, the left engine cowling made contact with the mechanism of the airbridge. The impact caused a three-inch diameter hole in the engine intake lip and slight deformation to the stand mechanism. There were no injuries to the 18 passengers or 6 crew members on board, and no ground personnel were hurt.
The investigation
The AAIB investigation examined the functionality of the AGNIS and PAPA visual docking systems, as well as the actions of the ground crew. It was established that the commander had misinterpreted the guidance provided by the parking aids. Specifically, the pilot mistook an extinguished emergency stop sign for a potential stopping signal and believed a ground crew member on the right side of the stand was a marshaller.
Investigators also reviewed the response of the ground staff. A Traffic Officer observed the overrunning aircraft but was unable to activate the emergency stop signal because she could not locate the activation button. Simultaneously, the GPU crewmember, who was responsible for placing chocks, did not intervene because he believed the pilot was in control and did not consider signaling the aircraft to stop to be part of his specific duties. The investigation found that the parking system used was not compliant with ICAO standards, as it was designed primarily for the pilot in the left seat and required the pilot to turn their head to view the stopping guidance.
Findings
- The commander misunderstood the instructions provided by the visual parking aids while searching for a positive stop indication.
- The pilot's misinterpretation of the docking system and the lack of clear stopping guidance contributed to the overrun.
- The emergency stop signal was not activated due to confusion among ground staff regarding the location of the button and their specific responsibilities during the arrival process.
- The existing visual docking guidance system was not optimized for the pilot's view from the cockpit, necessitating head movement that could lead to errors.