What happened
On 13 April 2019, a Rolladen Schneider LS8-18 glider, registered F-CIBD, was performing a local flight near Avize, France. The flight, operated by the Association Aéronautique du Val d’Essonne (AAVE), began with a towed takeoff from Buno-Bonnevaux aerodrome. The pilot followed a planned route passing over Villeneuve-l’Archevêque and Épernay-Plivot.
At approximately 16:40, after passing Épernay-Plivot, the pilot began the return leg of the flight. About three minutes later, while flying at an altitude of roughly 630 meters over an agricultural area, the aircraft experienced a sudden loss of control. The glider struck the ground in a vineyard, resulting in one fatality and the destruction of the aircraft.
The investigation
The BEA investigation utilized data from the aircraft's FLARM system and a GNSS-tracking application from the pilot's mobile phone to reconstruct the flight path. Analysis of the flight data revealed that in the final minute of flight, the glider's ground speed was approximately 110 km/h, with an estimated airspeed between 85 and 90 km/h. This was followed by a rapid descent of about 650 meters over a horizontal distance of less than 300 meters.
The investigation also examined the cockpit and the pilot's position. While the 4-point harness was found buckled on the seat, the pilot's parachute was found several meters away from the cockpit, suggesting the pilot was not secured in the harness at the time of impact. Ground tests demonstrated that when wearing a back parachute, a pilot may mistakenly believe they are restrained, and it is physically impossible to fasten or unfasten the harness buckle once seated.
Findings
The investigation established that the accident was likely caused by an aerological condition leading to an asymmetric stall or autorotation. The pilot was flying in turbulent conditions with convective air masses, and the decrease in airspeed during a turn likely triggered a stall. The LS8-18 is known for having a sudden stall characteristic that can lead to an abrupt nose-down attitude.
Contributing factors to the inability to recover from the loss of control included:
- The pilot was not wearing the safety harness.
- The sudden and abrupt nature of the stall in the LS8-18 model.