What happened
On 25 May 2004, a mid-air conflict occurred in the airspace southwest of the Geneva TMA. The incident involved a CL604, registration D-ASTS, operating a commercial flight from Stuttgart to Geneva, and a private PA-32, registration F-GSIX, flying under visual flight rules (VFR) from Cannes-Mandelieu to Geneva.
At approximately 08:55 UTC, the F-GSIX entered the Geneva TMA class C airspace at flight level FL 83 without having received the necessary clearance. At the same time, the D-ASTS was on an arrival route, descending through flight level FL 81. The two aircraft were on converging trajectories in opposite directions. The minimum separation reached during the encounter was a lateral distance of 1.9 NM and an altitude difference of only 400 ft.
The investigation
The investigation examined the coordination between Chambéry and Geneva air traffic control units. It was established that the Chambéry controller instructed the F-GSIX to contact Geneva Information but failed to instruct the pilot to descend below 5500 ft to avoid the class C airspace. Furthermore, the investigation found that the Chambéry controller did not perform the required telephone coordination with Geneva authorities before handing over the VFR traffic.
Radar analysis confirmed that the Short Term Conflict Alert (STCA) was triggered at 08:55:31. The investigation also reviewed the crew's response to the Traffic Collision Avoidance System (TCAS) alerts. While the D-ASTS crew received a resolution advisory (RA) to climb, the pilot chose not to comply with the instruction, believing the conflicting traffic was under control.
Findings
- The F-GSIX entered controlled class C airspace without authorization.
- The Chambéry controller failed to provide the necessary altitude restriction to the VFR pilot to prevent airspace infringement.
- Lack of timely coordination between the Chambérý and Geneva control sectors contributed to the loss of separation.
- The crew of the D-ASTS did not follow the TCAS resolution advisory, which is a critical safety violation.