What happened
On August 1, 2010, a Centrair C201 Marianne glider, registration F-CBLB, was conducting a local flight near the Puy aerodrome. Following a command from the chief pilot to return to the airfield due to deteriorating weather conditions, the pilot began the return flight. During this phase, the pilot performed a series of large-amplitude maneuvers involving significant changes in pitch, ranging from +45° to -40°.
During a high-speed left turn, the aircraft entered a stall and subsequently inverted. The pilot attempted to recover by pulling back on the elevator, which resulted in a vertical dive. During this dive, the airspeed increased to approximately 270 km/h, exceeding the aircraft's maximum speed (VNE) of 230 km/h. This led to a phenomenon of aeroelastic flutter, causing the wings to disintegrate in flight. The aircraft crashed into a wooded hillside, resulting in two fatalities.
The investigation
The investigation utilized data from a GPS installed on the pilot's mobile phone and video footage recovered from a camcorder belonging to the passenger. The video recording provided critical insights into the aircraft's instruments and the flight's final moments, showing the slip indicator and the movement of the cockpit canopy's yarn thread, which confirmed asymmetric flight. The analysis of the wreckage revealed that the airframe had been subjected to extreme mechanical stresses, leading to the structural failure of the wings.