What happened
On 14 July 2017, a Schempp Hirth Ventus-2CxT glider, registration G-TABB, was engaged in a private soaring flight in the Hautes-Alpes region of France. After taking off from the Serres La Bâtie-Montsaléon aerodrome in the morning, the pilot was performing slope soaring maneuvers near the Crête de Peyrolle. Around 16:27, the pilot communicated via radio that he was returning to the aerodrome due to cloud cover near Mont-Cenis lake.
Flight data from the onboard LX9000 computer indicates that during the final minutes of flight, the glider crossed the ridge to the east slope of the Grande Peyrolle peak. The aircraft entered a right-hand turn with a decreasing altitude and a reduction in true airspeed. In the final recorded seconds, the glider's airspeed dropped to approximately 89 km/h (75 km/h indicated airspeed). The aircraft subsequently struck the terrain at an altitude of 2,470 m, resulting in one fatality and the destruction of the aircraft.
The investigation
The investigation focused on the wreckage found in a difficult-to-access area of the Crête de Peyrolle. Investigators examined the airframe and found that the fuselage and right wing tip struck the slope at a high horizontal speed with a steep bank angle exceeding 45 degrees. The engine was not deployed, and the right wing air brake was retracted at the time of impact.
Analysis of the oxygen system revealed that the electronic delivery device was switched to the OFF position, meaning the pilot was not receiving supplemental oxygen during the final phase of flight. The investigation also reviewed the pilot's flight experience, medical history—noting the use of blood pressure medication—and the meteorological conditions, which included potential for strong downdrafts and turbulence on the lee side of the ridge.
Findings
- The glider was flying at an indicated airspeed of approximately 75 km/h, which was below the recommended minimum flying speed for the aircraft's configuration.
- The pilot may have been caught by unexpected turbulence, a downdraft, or wind shear while maneuvering at a low speed, leading to a stall or loss of control.
- The pilot's physiological state may have been compromised; while major hypoxia is unlikely, the lack of oxygen delivery, combined with the physical strain of prolonged high-altitude flight and the use of cardiovascular medication, may have reduced the pilot's ability to manage the aircraft in turbulent conditions.
- The aircraft's flight path suggests the pilot may have inadvertently crossed into the more turbulent lee side of the ridge while attempting to utilize available uplifts.