What happened
On July 16, 2023, a SCHEMPP HIRTH DISCUS 2C glider, registered OE-5751, was conducting a local mountain flight near the Gap-Tallard aerodrome in France. The pilot, part of an Austrian flying club visiting the region, had performed a towed takeoff earlier that afternoon and had been utilizing thermal lifts to navigate the mountainous terrain.
At approximately 15:30, the pilot executed a U-turn toward the southwest. While the flight had initially been successful in finding lift, the aircraft began a steady descent at a rate of 1 m/s starting around 15:54. At 16:07, the glider experienced a sudden and severe drop, with the rate of descent accelerating to 32 m/s. Shortly thereafter, the aircraft collided head-on with a mountain slope at an altitude of approximately 2,700 m. The impact resulted in the death of the pilot and the total destruction of the glider.
The investigation
The investigation focused on the aircraft's flight data, the wreckage, and meteorological conditions. Analysis of the on-board computer confirmed the sudden loss of altitude. Examination of the wreckage showed that the forward section and wing leading edges were destroyed, though the rear section remained relatively intact. While the speed brakes were found in the extended position, investigators could not confirm if they were deployed prior to impact or caused by the collision.
Mechanical inspections of the flight controls found the pitch and yaw linkages to be continuous, though damage to the roll control linkages was noted due to the impact. Investigators also examined the aircraft's oxygen system and the Emergency Locator Transmitter (ELT), noting that the ELT antenna had ruptured during the crash.
Meteorological data indicated significant atmospheric instability. While visibility was excellent, the region was experiencing strong south-westerly winds with gusts between 25 and 30 knots. The AROME model and local reports suggested intense turbulence in the lower layers, driven by strong thermal lifts and valley breezes caused by high temperatures.
Findings
- The investigation found no mechanical or technical failure in the aircraft that could account for the sudden descent.
- Strong atmospheric turbulence or an aerological phenomenon may have caused the pilot to lose control of the aircraft.
- Pathological examinations identified a medical context that could have predisposed the pilot to cardiac rhythm disorders, though no definitive evidence of an in-flight medical event was found.