What happened
On March 21, 2001, at Geneva Airport, a Swissair Airbus A321 was performing a routine commercial takeoff from runway 23. Simultaneously, a private Beechcraft 55, registration HB-GEC, was taxiing toward taxiway Zulu. Due to a prior aircraft blocking a nearby intersection, the pilot of the HB-GEC was directed to taxi via an external route.
During the maneuver, the pilot of the HB-GEC crossed the runway boundary and approached the active runway, eventually coming to a sudden stop approximately 20 meters from the runway edge. The aircraft had bypassed active stop bars and taxiway markings. The pilot of the Airbus A321 continued the takeoff roll, rotating at a distance of roughly 800 meters from the position of the HB-GEC.
The investigation
SUST examined the radio communications and ground movements leading up to the incident. The investigation established that the Tower controller had coordinated with the Apron controller to move the HB-GEC to a different holding point. During the transfer of communication between the Traffic and Apron frequencies, the controller used imprecise phraseology.
The investigation also found that the HB-GEC was traveling at a high speed and failed to stop at the illuminated stop bars. While the pilot of the HB-GEC believed they had received authorization to cross the runway, the investigation determined that the instruction was actually a transfer of frequency that was poorly phrased and potentially truncated. Furthermore, the Apron controller did not react to an incorrect readback from the pilot, and the Ground controller did not intervene until the aircraft had already approached the runway.
Findings
- The primary cause was a misunderstanding caused by inappropriate phraseology used by the Traffic controller.
- The pilot of the HB-GEC performed an incorrect readback of the instructions, which the controller failed to correct.
- The Apron controller failed to react to the pilot's incorrect readback.
- The HB-GEC proceeded past active stop bars while they were illuminated.
Safety action
- It is necessary to activate the stop bars for taxiways Zulu and Yankee whenever the runway and taxiway lighting systems are switched on, including during Category I instrument approaches.
- The AIP should be updated to state that frequency changes must be executed immediately as instructed.