What happened
On 30 May 2019, a Centrair Pégase C101 A, registration F-CGSH, was engaged in a local flight near the Saint-Girons Antichan aerodrome in France. After approximately two hours and 45 minutes of flight time, the pilot was performing slope soaring maneuvers near a forested area.
During the flight, the pilot encountered an inversion layer at approximately 1,500 meters, which prevented further ascent. In an attempt to bypass this layer, the pilot maneuvered to the south side of the terrain. After an unsuccessful attempt to penetrate the inversion, the pilot returned to the north side of the slope and regained some altitude. However, while attempting a subsequent turn toward the south, the aircraft encountered a downdraught. This loss of lift caused the glider to descend into the forest canopy, resulting in a collision with treetops and leaving the aircraft resting in a nose-down position.
The investigation
The BEA reconstructed the flight path using data from the aircraft's FLARM computer. The analysis revealed that the pilot had performed two similar passes over the accident slope: the first at approximately 15:45 and the second at approximately 17:15. Both passes occurred at low altitudes, between 30 and 40 meters. The investigation also noted that the ground speed during the second pass was roughly 100 km/h, which was 10 km/h slower than the initial pass.
Findings
Several factors contributed to the accident:
- The aerological conditions had deteriorated by late afternoon, with weakened thermal uplift and diminished slope effects.
- The pilot's flight path lacked sufficient energy margins to maintain altitude relative to the terrain.
- Fatigue and impaired judgment resulting from the long duration of the flight and the strenuous effort to find usable lift likely prevented the pilot from recognizing that the wind and lift conditions had changed.
- A strong motivation to continue the flight despite the challenging conditions contributed to the decision to fly close to the terrain.