What happened
On June 22, 2016, an instructor and a student pilot were conducting a mountain flight training session near Authon, France. After departing from the Château-Arnally Saint-Auban airfield, the crew flew a circuit toward the Vercors mountains, utilizing various thermals. During the return leg, the student pilot was flying the Schempp Hirth Arcus, registration F-CVDF, while following the ridges of the southern slope of Mont Jouère in a ridge-soaring maneuver.
As the aircraft approached the Cirque des Monges, the instructor requested a right-hand turn. During this maneuver, the glider encountered severe downdrafts. The instructor took control of the aircraft, attempting to level the wings and maintain airspeed, but the right wing struck a nearby ridge. The impact caused the glider to spin to the right before sliding down the slope and coming to rest in a ravine.
The investigation
Investigators examined the wreckage and found no evidence of mechanical failure prior to the impact, confirming that the right wing struck the terrain first. Meteorological conditions at the site included visibility of over 10 km and scattered clouds with bases between 2,300 and 2,500 meters. While surface winds were light, there were active valley and slope breezes.
The instructor, an experienced pilot with over 6,000 flight hours, noted that the morning briefing indicated a south to southeast wind at altitude. However, other pilots flying in the area that day reported encountering winds from the east to southeast. The investigation focused on why the crew encountered such significant sink during the turn.
Findings
- The pilot was a student undergoing an initial mountain flight training course.
- The instructor did not anticipate the presence of strong downdrafts in the Cirque des Monges due to the wind direction encountered earlier in the flight.
- The instructor failed to recognize the specific wind conditions within the Cirque des Monges, which placed the aircraft on the leeward side of the terrain.
- The proximity to the ridge during the ridge-soaring maneuver left insufficient margin to recover from the sudden loss of lift before the collision occurred.
One fatality and one injury were recorded.