What happened
On July 25, 1999, at approximately 18:50 local time, an Airbus A310 was taxiing on taxiway "ALFA" toward taxiway "KILO" for departure from runway 07L at Frankfurt Airport. During the maneuver, the aircraft's left wing struck the right vertical stabilizer of a stationary Boeing 7 and37-500 located on taxiway "JULIETT". The collision caused significant damage to both aircraft, including the tearing of components from the A310's winglet and leading edge, and damage to the Boeing's stabilizer and rudder. There were no injuries to the crews, though both aircraft sustained heavy damage.
The investigation
The BFU investigation involved analyzing flight data recorders (FDR) from both aircraft and interviewing the pilots. The investigation reconstructed the position of the Boeing 737 using impact marks and a photograph taken by a ground vehicle. The investigation also included an interview with the air traffic controller (ATC) in charge of the area. The investigation established that the Boeing 737 was positioned at the CAT II/III marking, significantly behind the expected holding point. The A310 crew was engaged in radio communications with ATC regarding a departure offer from taxiway "KILO" at the time of the impact.
Findings
- The crew of the Boeing 737-500 had decided to wait for a Boeing 747 to depart before taxiing forward to the actual holding point, which placed the aircraft's tail in a position that obstructed the path of taxiway "ALFA".
- The Airbus A310 crew noticed the Boeing 737 but assumed that clearance was maintained because the aircraft was in a designated taxiway.
- The A310 crew was distracted by radio communications with ATC during the critical period when the collision could have been avoided.
- The air traffic controller was managing high workload, overseeing multiple aircraft, and did not realize the Boeing 737 was not at the expected holding position.
- The use of the phrase "hold short of" is imprecise, as it allows an aircraft to stop an indeterminate distance before the marking.