What happened
On July 16, 2019, a DG-1000T motor glider, registration D-KIST, departed from the Sisteron Vaumeilh aerodrome for a local flight. The aircraft was operated by a private pilot accompanied by one passenger. After being towed, the pilot released the cable near the Rochers de Hongrie at an altitude of approximately 1,200 meters. Following the release, the pilot began performing ridge soaring maneuvers, including spirals and alternating figure-eight turns along the terrain. During these maneuvers, the aircraft lost control and collided with the landscape, resulting in two fatalities and the destruction of the glider.
The investigation
The investigation utilized data from the Open Glider Network (OGN) to reconstruct the flight path, as the onboard flight computers were too damaged to extract data. Analysis of the wreckage revealed that the aircraft struck a wooded slope with a gradient of 30 to 40 degrees. The impact trajectory was nearly vertical, and the aircraft's structural failures were entirely consistent with the collision with trees and the ground.
Examination of the flight controls showed no mechanical anomalies. At the time of the accident, the engine, landing gear, and airbrakes were all retracted, and the canopies were properly locked. Meteorological data indicated moderate turbulence and wind gusts of up to 12 knots at the site. The pilot, a highly experienced individual with over 1,340 flight hours, had been flying in the area regularly for several years.
Findings
- The pilot was performing ridge soaring maneuvers with a bank angle exceeding 30 degrees.
- Flight path analysis showed that the aircraft's airspeed was decreasing during the final seconds of flight, approaching the stall speed.
- The pilot lost control of the aircraft during a right-hand turn.
- The altitude maintained during the ridge soaring maneuvers was insufficient to allow the pilot to recover control before the impact.