What happened
On June 18, 2012, a Glaser Dirks DG 400 motor glider, registration D-KBEM, departed from the Serres la Bâtie-Montsaléon aerodrome for a self-launch flight. After an initial period of powered flight, the pilot shut down the engine at an altitude of 1,250 meters. Following a brief period of gliding, the engine was restarted for approximately two minutes before the pilot resumed powered flight.
While performing several passes along a ridge oriented southeast to northwest, the pilot attempted a right-hand turn. During this maneuver, the aircraft lost control and struck the ground at an altitude of 710 meters near La Piarre. GNSS data indicated that the groundspeed decreased significantly during the turn, dropping to values near 80 km/h prior to the impact. The accident resulted in one fatality and the total destruction of the aircraft.
The investigation
The investigation focused on the flight path and the mechanical state of the aircraft. Analysis of the wreckage revealed no mechanical failures or external factors that contributed to the accident. The pilot's flight history showed 1,695 total flight hours, with 6 hours on this specific type and 8 hours of flight within the preceding three months. Notably, the pilot lacked recent experience flying in the Alpine region.
Meteorological conditions at the time of the accident included a 10-knot wind from 180°, visibility exceeding 10 km, and temperatures of 20 °C. While altocumulus and cumulus clouds were present with bases around 3,000 meters, some showers were noted to the west of the aerodrome.
Findings
- The primary cause of the accident was insufficient monitoring of airspeed by the pilot during the right-hand turn, which led to an aerodynamic stall.
- The pilot's lack of recent experience operating in mountainous terrain may have contributed to the loss of control.