What happened
On February 15, 2003, a private Ambassador DR100, registration F-PDDL, was flying a VFR route from Courchevel to Merville-Calonne. While traversing the Geneva TMA, the aircraft encountered unfavorable weather conditions. The pilot entered the controlled Class C airspace without prior authorization and, crucially, had not activated the aircraft's transponder. Because the transponder was inactive, air traffic controllers could only detect the aircraft via primary radar, appearing as a small synthetic square on their screens.
Simultually, a commercial Eurocopter SA365, registration HB-ZBY, was performing an IFR approach to Geneva on the ILS runway 05. As the pilot of F-PDDL eventually contacted Geneva Information and was assigned a transponder code, the aircraft became clearly visible on the radar. This sudden identification revealed a high-risk conflict. The arrival controller immediately identified the danger and ordered the helicopter to descend rapidly to avoid the oncoming aircraft.
The two aircraft crossed paths at a distance of approximately 2.2 NM horizontally and only 200ft vertically.
The investigation
The investigation examined the operational environment and the technical detection capabilities during the incident. It was established that the TMA control position was unstaffed at the time, with the TMA frequency being monitored by the Approach controller. Due to high traffic volume, the Approach controller was heavily engaged in coordination and was unable to directly manage the TMA frequency.
Investigators found that the pilot of F-PDDL was flying VFR on top of a cloud layer. While the aircraft was detectable via primary radar, this required the controllers to have the "QuickLook" function active. Furthermore, the investigation noted that the Flight Information Center (FIC) operator used an incorrect registration when communicating with the pilot, referring to the aircraft as F-PDLL.
Findings
- The primary cause of the near collision was the unauthorized entry of F-PDDL into the controlled Geneva TMA.
- The lack of an active transponder on F-PDDL significantly limited the controllers' ability to identify and manage the conflict early.
- High traffic density and the unstaffed nature of the TMA control position prevented proactive management of the unauthorized entry.
- There was a lack of coordination between the Flight Information Center and the Arrival radar controller regarding the movement of the aircraft.