What happened
On the night of 8 February 2007, a serious airprox incident occurred in the airspace controlled by the Geneva Upper Area Control Centre (UAC West), near Lake Annecy. The incident involved a Tupolev Tu-154M, registration UN85713, operated by Berkut State Air Company, and a Lockheed C-130 Hercules, registration 7T-W HB, operated by the Algerian Air Force.
The Tupolev, flying flight number BEC 016, was climbing from Lyon Saint-Exupéry toward Almaty. Simultaneously, the C-130 was cruising at flight level FL 250 on a cargo flight from the Czech Republic to Algeria. During the climb, the trainee radar controller cleared the Tupolev to flight level FL 260. However, this instruction placed the aircraft on a path that would intersect the flight level of the C-130, which was traveling in the opposite direction.
As the aircraft approached each other, the Short Term Conflict Alert (STCA) was triggered in both the Geneva and Marseille control centers. The trainee controller initially cleared the Tupolev to FL 250—the same level as the Hercules—before a supervisor intervened to order a maximum rate climb to FL 300. Despite the intervention, the aircraft passed within 0.4 NM laterally and only 100 feet vertically. The encounter was only resolved after the aircraft's TCAS systems issued conflicting resolution advisories.
The investigation
The investigation examined the operations of the Geneva UAC West, which had recently transitioned to a "stripless" electronic control system. Investigators reviewed the performance of the dynamic scanning tool (DST) and the conflict detection alerts. The investigation also looked into the coordination between the Geneva and Marseille control centers, specifically regarding the transfer of communication and the monitoring of aircraft climbing through different flight levels.
Findings
- The trainee controller cleared the Tupolev Tu-154M to a flight level that conflicted with the Lockheed C-130 Hercules.
- The trainee controller acknowledged a DST conflict alert but validated the alert without fully understanding the content, effectively dismissing the warning.
- The trainee controller's attention was diverted by a separate separation alert in a different region of the airspace.
- The radar coordinator was preoccupied with consulting flight plan data and was not aware of the specific clearance being issued to the Tupolev.
- The supervisor (coach) was also distracted by a separate STCA alert in the Aosta region at the time the conflict was developing.
- The aircraft passed extremely close to one another, with a vertical separation of only 100 feet.