What happened
On the evening of August 17, 2002, a Cosmos Phase 2 ultralight, identified as 21-NN, was conducting a local flight near Oucherotte. The pilot intended to fly over two residences located in a valley. After flying along an east-west axis at approximately 150 feet above the houses, the pilot attempted a very tight left-hand turn to avoid a mountain slope. During this maneuver, the aircraft entered a stall and struck the treetops.
The investigation
The investigation examined the flight circumstances, the pilot's experience, and the environmental conditions at the time of the accident. Meteorological data from the nearby Dijon aerodrome indicated light winds, visibility greater than 10 km, and a temperature of 28 °C. Post-accident engine testing confirmed that the powerplant was functioning correctly.
Findings
Investigators determined that the accident resulted from a stall during a steep turn at low altitude. The pilot failed to apply sufficient power to compensate for the loss of lift and the reduction in engine performance caused by the high ambient temperature. The low altitude of the maneuver left the pilot with insufficient margin to recover control of the aircraft before impact.
As a result of the collision, the aircraft was destroyed, and the two occupants—the pilot and one passenger—sustained slight injuries.