What happened
On the afternoon of August 27, 2008, a Schleicher ASH 26 E motor glider, registration D-KAGM, was performing a local flight in the Gapençaises Alps. The pilot had departed from the Serres airfield earlier that morning. Following the flight, the pilot failed to return, prompting authorities to launch a search operation. The wreckage was located the following day at an altitude of 1,680 meters on the northern slope of the Tête de la Clappe, near the Crête de la Barre.
Evidence from the impact site indicated that the aircraft followed a very low-altitude trajectory after crossing the ridge. The aircraft initially struck the tops of two larch trees, and approximately ten meters later, the wing detached after hitting two additional trees. The main wreckage was found thirteen meters away from the detached wing.
The investigation
The investigation focused on the wreckage, the flight path, and the pilot's experience. Analysis of the debris showed that the engine was in the retracted position at the time of the accident. No mechanical failures capable of contributing to the crash were identified. Data retrieved from the aircraft's FLARM® system allowed investigators to reconstruct the flight path from the takeoff at Serres to the immediate vicinity of the accident site.
The pilot was an experienced flyer with over 1,200 total flight hours, including 150 hours on this specific type. He was highly knowledgeable in aerodynamics and was familiar with the local region, having flown in the Southern Alps annually since 2003. There was no evidence of impairment, as the pilot had consumed no alcohol prior to the flight.
Findings
Investigators determined that the accident was caused by the decision to continue the flight at a low altitude on the leeward side of the slope. The investigation also noted that the pilot failed to sufficiently account for the effects of orographic air movements, which likely impacted the aircraft's flight path during the ridge crossing.