What happened
On August 25, 2014, a Cessna 1 72, registered F-HPGX, was conducting a flight demonstration for a group of school children near Périgueux, France. The pilot was flying a circular route at approximately 1,800 ft with a cruising speed of about 80 kt. While maneuvering west of the city, the pilot spotted a fast-moving aircraft on the left flank. Upon looking forward, the pilot encountered a second aircraft directly ahead at the same altitude.
Simultaneously, a pair of Dassault Aviation-Dornier Alphajet NG aircraft, registered F-UHRP and another unnamed unit, were performing low-altitude attack training. The flight was traveling at a high speed of approximately 420 kt. The wingman of the military formation detected the Cessna 172 and initiated a left-hand avoidance maneuver. However, the closing speed was so great that the aircraft passed extremely close to the light plane, with the pilot of the Cessna 172 reporting a loud noise and a violent jolt, fearing a physical impact.
The investigation
The BEA examined the flight sequences, cockpit video from the military aircraft, and the visual scanning techniques used by both crews. The investigation noted that the Cessna 172 pilot was focused on specific navigation points for the educational flight, which likely limited his external surveillance. The military crew was operating in a high-workload environment, performing low-altitude maneuvers that made it difficult to notify local air traffic controllers of their presence.
Findings
- The near collision was caused by the failure of the "see and avoid" concept due to the inability of both crews to detect each other early enough during a very high-speed closing encounter.
- The lack of onboard detection equipment, such as ACAS or radar, on the military aircraft, acted as a contributing factor.
- The high speed of the Alphajet NG aircraft created a very narrow visual window for the slower aircraft to detect them.
- The pilot of the Cessna 172 was partially preoccupied with navigation tasks required for the flight demonstration.