What happened
On July 22, 2023, a Schempp_Hirth Arcus glider, registration F-CVMP, was conducting a local flight for instruction near Puigmal, France. The flight began with a towed takeoff from the La Llagonne - La Quillane aerodrome. After releasing the tow cable at approximately 2,300 meters, the crew proceeded south along the Llo valley.
As the instructor took control to demonstrate techniques for utilizing weak uplifts, the aircraft approached a rocky spur. While attempting to fly over the obstacle to reach a larger cirque further down the valley, the glider encountered a sudden downdraft. This downward air movement caused the aircraft to lose altitude rapidly, leading to a collision with the terrain. The fuselage struck the ground, causing the left wing to detach, and the wreckage slid down a steep slope before coming to rest against a tree.
The investigation
The BEA examined the wreckage and analyzed data from the aircraft's on-board computers, including the PowerMouse and LX9000 systems. The investigation established that the aircraft's mechanical systems were functioning normally prior to the impact, and no malfunctions were identified during the examination of the wreckage. Meteorological data confirmed a south-westerly wind of approximately 11 knots and the presence of weak vertical air movements.
Findings
- The primary cause of the accident was the loss of altitude due to a strong downburst while the aircraft was positioned on the downwind side of a ridge.
- The instructor's attempt to clear the rocky spur left insufficient margin to divert the aircraft when the descending air current was encountered.
- Contributing factors included the difficulty of anticipating localized downdrafts on the lee side of the terrain.
- The investigation also noted potential overconfidence, possibly related to the instructor's frequent experience flying in this specific sector.