What happened
On March 19, 2017, a Glaser Dirks DG1001M motor glider, registration D-KVDG, departed from the Sisteron Vaumeilh airfield for a private flight. The aircraft was carrying a pilot and one passenger. After approximately 30 minutes of flight, the glider struck trees and collided with the ground in a stream near Le Vernet. The impact resulted in one fatality and left the pilot with serious injuries. The aircraft was destroyed in the accident.
The investigation
The BEA examined the wreckage and flight data from several onboard computers. Physical evidence showed the engine pylon was extended in a nearly vertical position and had suffered structural deformation. The engine's power control was set to full throttle, and the fuel valve was open. Flight data analysis revealed that after the engine deployment process was initiated, the aircraft followed a primarily descending trajectory.
Investigators also reviewed the manufacturer's flight manual, which specifies that engine deployment should be performed at altitudes above 1,000 meters when flying over hostile terrain and at recommended speeds between 85-95 km/h. The investigation also noted that the landing gear was retracted at the time of impact, suggesting the pilot may not have intended to perform an emergency landing in the nearby fields.
Findings
- The pilot initiated the engine deployment sequence at an altitude and speed that did not comply with the manufacturer's recommended parameters.
- The engine deployment sequence was likely interrupted prematurely due to high aerodynamic resistance, as the aircraft's ground speed remained above the recommended deployment range.
- A recorded "spindle drive fuse failure" suggests that the electrical effort required to extend the pylon against the wind exceeded the system's limits, preventing the engine from starting.
- The pilot's flight path did not show any maneuvers indicating an intention to land in the available fields prior to the crash.