What happened
On August 2, 2004, a DG-400 motor glider, registration D-KLET, departed from Kempten, Germany, for a cross-country flight intended to span the region between Zurich, Switzerland, and Innsbruck, Austria. During the flight, the pilot communicated via radio at approximately 17:00, reporting a position over the San Bernardino Pass at an altitude of 3,800 meters and expressing intentions to continue eastward through the Engadin valley.
After failing to return to the departure airfield that evening, the aircraft was reported missing. A search operation involving multiple aircraft and helicopters was initiated. On August 4, 2004, a hiker discovered the wreckage on the western slope of Corn Alv in the Val d'Agnel region, near Bivio, Switzerland. The aircraft had struck a rocky peak at a relatively low forward speed in a nearly horizontal flight attitude. The impact caused the total destruction of the aircraft and resulted in one fatality.
The investigation
The investigation, conducted by the Swiss authorities, examined the wreckage, the pilot's medical condition, and the environmental factors at the time of the accident. Because all flight recording devices were destroyed upon impact, investigators could not reconstruct the exact flight path.
Technical examination of the DG-400 revealed no evidence of pre-existing mechanical defects. The engine was in the retracted position, and the aircraft's weight and center of gravity were within permissible limits. Meteorological data indicated that while the general weather was stable, the area experienced strong northwesterly winds, which produced significant turbulence and downdrafts near the terrain.
Medical examinations of the pilot provided critical insights. While toxicology reports showed no presence of drugs, alcohol, or underlying diseases, the autopsy revealed that the pilot was in a state of extreme dehydration and hunger, characterized by highly concentrated urine and an empty stomach.
Findings
- The accident was likely caused by a loss of control while flying in close proximity to the terrain, leading to the collision.
- Turbulent airflow and downdrafts near the mountainside contributed to the difficulty of the flight.
- The pilot's physiological state, specifically severe dehydration and hunger following several days of long-duration flights, may have impaired his concentration and decision-making abilities.