What happened
On March 12, 2002, at 16:32, a Rolladen Schneider LS 8 A glider, registration F-CGZM, crashed into the terrain near the Clos Giraud area in the Massif des Imbertons. The pilot departed from the Château-Arnoux Saint-Auban aerodrome at 13:28. After reaching an altitude of 4,300 meters, the aircraft began losing altitude while flying through air masses that provided no lift. In an attempt to find rising air, the pilot initiated a 360-degree left turn near the southern flank of the Imbertons massif. As the aircraft failed to find lift, the pilot began a right-hand turn. During this maneuver, the glider lost airspeed and altitude, ultimately striking the terrain. The impact resulted in the death of the pilot and the total destruction of the aircraft.
The investigation
Investigators utilized GPS data recovered from the aircraft to reconstruct the flight path, speed, and altitude evolution. The data revealed that at 16:30:52, while at an altitude of 1,082 meters, the pilot had the opportunity to fly directly toward the Crots ultralight landing strip, located only 2.6 km away at an altitude of 780 meters, by abandoning the 360-degree turn. Additionally, an instructor flying in the vicinity reported hearing several radio communications in German, which indicated that the pilot of F-CGZM was experiencing difficulties and had considered diverting to the Crots landing site.
Findings
- The primary cause of the accident was the delayed decision to interrupt a flight phase within an air mass that did not permit the use of thermals or lift.
- Meteorological conditions at the site included turbulent winds of 8 m/s with gusts up to 12 m/s, driven by the channeling effect of the Durance valley.
- The specific terrain orientation and the Foehn effect created conditions that were unfavorable for finding the necessary lift to maintain altitude.
- The pilot's attempt to execute a wide turning maneuver in sinking air led to a critical loss of airspeed and altitude.