What happened
On July 31, 1999, at 12:20 UTC, a Piper PA46, registration D-ETJG, was operating a visual flight rules (VFR) flight from Annecy to Saarbrücken. While climbing through 6,500ft near Mont-Salève, the aircraft entered the Geneva Terminal Control Area (TMA) Class C airspace without prior authorization or radio contact with the controller.
Upon establishing contact on the TMA frequency, the controller immediately identified a conflict with an opposing instrument flight rules (IFR) aircraft, Lufthansa 32702, an Airbus A319. The Lufthansa flight was descending through 7,000ft on a visual approach to Geneva. The controller issued an immediate avoidance instruction to the Lufthansa crew, directing a 10-degree right turn. Simultaneously, the pilot of the D-ETJG was instructed to descend to 3,000ft and turn south. During the encounter, the Lufthansa crew reported a TCAS alert. The two aircraft passed within 1.9 NM of each other with an altitude separation of only 100ft.
The investigation
The investigation, conducted by the Swiss Transportation Safety Investigation Board, relied on radar tracks and radio communication transcripts. The inquiry examined the movement of both aircraft and the responsiveness of the air traffic controllers. The investigation confirmed that the D-ETJG entered the controlled airspace without a transponder code or radio contact. The investigation also noted that the weather conditions were favorable, with 10 kilometers of visibility and scattered clouds.
Findings
- The primary cause of the incident was the unauthorized entry of a VFR aircraft into Class C airspace.
- The D-ETJG entered the Geneva TMA at 6,500ft while climbing toward flight level 75 without requesting clearance.
- The pilot of the D-ETJG may not have accurately identified the boundaries of the Geneva TMA or may have failed to monitor the correct radio frequency upon entry.
- Air traffic controllers reacted promptly to the conflict, providing both aircraft with necessary avoidance instructions to prevent a collision.