What happened
On 10 October 1999, a McDonnell Douglas MD1le, registration N1756, arrived at London Heathrow Airport following a scheduled flight from Miami. As the aircraft taxied into stand K23, the pilot attempted to self-park using the AGNIS and PAPA guidance systems. The pilot, accustomed to receiving marshalling assistance, was monitoring the AGNIS light bars to maintain the centreline but was waiting for a specific light change to signal the stopping point.
As the aircraft continued forward, it overran the designated parking position by approximately 15.75 metres. During this movement, the right engine nacelle struck a transit van that had been parked near the head of the stand. The impact caused scuff and scratch marks to the engine nacelle and pushed the van roughly 6 feet sideways. The aircraft came to a halt after the crew chief-ramp ran into the path of the aircraft to signal the pilot to stop. There were no fatalities and no injuries to the 212 passengers or 15 crew members on board.
The investigation
Investigators examined the use of the AGNIS (Azimuth Guidance for Nose-In Stands) and PAPA (Parallax Aircraft Parking Aid) systems. The AGNIS system provides centreline guidance via vertical light bars, while the PAPA system uses a black marker board to provide stopping guidance. The investigation established that the pilot had to alternate his focus between these two separate aids to park correctly.
At the time of the accident, the airline was transitioning to a new policy where aircraft would self-park on Kilo stands rather than using marshallers. While the stand's entry guidance controls had been moved to ramp level, the emergency stop functionality—which would have illuminated a 'STOP' sign at eye level—had not yet been installed on stand K23.
Findings
- The pilot was not aware that he would be required to self-park upon arrival at the stand, as he had previously relied on marshalling assistance.
- The pilot's reliance on the AGNIS lights led him to wait for a red light to signal stopping, whereas the AGNIS system does not provide stopping guidance.
- The presence of the ground vehicle on the apron was a significant factor, as the van was parked in an area that was technically an infringement of airport regulations.
- The crew chief-ramp's decision to park the van in a position that could obstruct the stand was identified as unwise due to congestion in the area.