What happened
On October 2, 2010, a Cessna 172 and an Aveko VL-3-B were flying in close proximity near Les Moëres, France, for the purpose of capturing aerial photographs of the newly acquired VL-3. The flight involved two pilots and two passengers, with one photographer positioned in the Cessna. After flying along the coastline and crossing into French airspace, the aircraft were maneuvering to capture various angles of the VL-3.
As the mission concluded, the pilot of the Cessna 172 initiated a left turn to return to the airfield. This maneuver was performed without prior radio announcement and without the pilot having the other aircraft in sight. During this turn, the leading edge of the Cessna's left wing struck the trailing edge of the VL-3's right wing. The impact severed the VL-3's right wing, causing the aircraft to enter a vertical spiral dive. The two occupants of the Aveko VL-3-B were killed upon impact with the ground. The pilot of the Cessna 172 managed to perform an emergency landing in a field, though the aircraft sustained heavy damage and eventually overturned.
The investigation
Investigators examined the flight paths, radio communications, and wreckage of both aircraft. The investigation established that the two aircraft possessed significantly different performance characteristics; the VL-3 is a much lighter, faster, and more agile ultralight compared to the Cessna. Furthermore, the different wing configurations (high-wing vs. low-wing) created visibility challenges between the two cockpits.
Radio logs revealed that while the pilots were communicating, they were instructed by Koksijde radio to switch frequencies. The investigation found that the pilot of the Cessna 172 did not verify that communication had been successfully established on the new frequency. Crucially, there was no radio call to announce the intention to change heading during the final turn.
Findings
- The collision was directly caused by the unannounced left turn performed by the Cessuna 172 while the pilot lacked visual contact with the other aircraft.
- A major contributing factor was the lack of adequate pre-flight planning and specific procedures for the formation flight.
- The pilots lacked specific training for flying in close formation.
- The significant differences in speed, climb rates, and visibility between the two aircraft types made maintaining a safe formation difficult without rigorous preparation.