Accident Overview
On 2 August 2004, a DG-400 motor glider, registered D-KLET, departed Kempten Airfield in Germany at 10:41 LT on a soaring flight toward the Zurich–Innsbruck area. The aircraft did not return and was reported missing. Wreckage was found on 4 August 2004 on the west slope of Corn Alv in Val d'Agnel, municipality of Bivio, Graubünden, Switzerland, at an elevation of 2829 m.
Flight History
The pilot had conducted long-distance flights of 4 to 10 hours daily for the preceding five days. On the day of the accident, he started his flight at 10:41. At approximately 17:00, he reported by radio to a fellow pilot that he was over the San Bernardino Pass at 3800 m and intended to continue eastward toward Engadin and then Kempten. The flight path could not be determined because all recording devices were destroyed. When the aircraft failed to return, the Rescue Coordination Centre in Münster declared the glider missing, and search operations were initiated. A hiker reported the wreck to the cantonal police at 17:06 on 4 August.
Crash and Wreckage
The motor glider struck a rocky outcrop on the west slope with relatively low forward speed in an almost horizontal attitude. The impact destroyed the aircraft. Examination of the controls and linkages revealed no pre-existing defects. No food containers, drink bottles, or headgear were found in or near the wreck. The engine was retracted at the time of impact. An emergency locator beacon (ELBA) was fitted but its antenna was torn off, preventing any signal transmission.
Medical Findings
Autopsy showed that the pilot died instantly from multiple injuries. Toxicology tests were negative for drugs, alcohol, and medication. The autopsy report noted pronounced dehydration: dry mucous membranes, only 50 ml of urine, an empty stomach, and strongly ketone-positive urine, indicating a state of dehydration and hunger. The report stated that such conditions are capable of impairing a pilot's ability to fly or leading to erroneous decisions.
Meteorological Conditions
Weather at the accident site was estimated from station data: 3/8 cloud cover with base at approximately 12 500 ft AMSL, visibility 40–60 km, northwest wind 10 kt gusting to 15 kt, temperature +9 °C, dew point -2 °C. Isolated cloud touches on terrain were noted. A helicopter pilot reported strong northerly winds causing turbulence and downdrafts on the Engadin side in the days around the accident.
Probable Cause
The accident is probably due to a loss of control near a slope, followed by a collision with the terrain. A temporary reduction of the pilot's fitness to fly may have played a role.