What happened
On December 7, 2009, at Geneva International Airport, a Pilatus PC-12/45, registration LX-LAB, was being moved from a RUAG maintenance hangar to a compensation area for compass adjustments. The aircraft was being operated by a mechanic in the left seat and a technician in the right seat, who was responsible for radio communications.
During the taxi, ground control instructed the aircraft to proceed to the CAT I holding point. However, the mechanic driving the aircraft failed to stop at the designated holding point and proceeded to cross the active runway. At the time of the crossing, a Galaxy aircraft, registration HB-IUT, was on its final approach and was in the flare phase of landing. The two aircraft passed within approximately 1,000 meters of each other at a closing speed of roughly 100 knots. The ground controller immediately identified the runway incursion and ordered the LX-LAB to accelerate to clear the runway quickly.
The investigation
The investigation by the BEAA examined radio communications, radar tracks, and statements from the crew of both aircraft as well as air traffic controllers. The inquiry established that the technician in the LX-LAB had correctly read back the instructions to proceed to the CAT I holding point, but his attention was diverted to observing the arriving HB-IUT. Meanwhile, the mechanic driving the LX-12 misunderstood the instruction, interpreting only the first part of the clearance as an authorization to proceed through the runway.
Findings
- The primary cause was a dangerous proximity between an aircraft in the flare phase and an aircraft crossing the runway without authorization.
- There was a significant lack of communication between the mechanic at the controls and the technician handling the radio.
- The maintenance crew lacked adequate training regarding movement area procedures.
- Existing airport regulations regarding aircraft movements conducted by maintenance personnel were insufficient.