DG-400 hits alpine slope; pilot found dehydrated after 7-hour flight

On 2 August 2004 the pilot of a DG-400 died on the west slope of Corn Alv in the Val d'Agnel at 2,829 m MSL; the aircraft was destroyed. He had self-launched from Kempten at 10:41 LT for a long mountain cross-country, after five consecutive days of 4-10 h flights. Last radio contact at ~17:00 LT placed him over the San Bernardino at 3,800 m, returning via the Engadin. The wreckage was found two days later. Impact was at low forward speed and near-horizontal attitude. The probable cause was a loss of control near a slope; a pronounced dehydration and hunger state at autopsy contributed.

1. Self-launch Kempten for mountain XC: At 10:41 LT the DG-400 self-launches from Kempten (Germany) for a long mountain cross-country toward the Zürich – Innsbruck area.
2. 5 consecutive 4-10 h XC days prior: On each of the five days preceding the accident the pilot has flown long cross-countries of 4 to 10 hours' duration — the accident flight follows a week of sustained high-workload soaring.
3. Turbulent slope environment: Across the days around the accident a strong north wind has been producing strong gusts and downdrafts on the Engadin slopes (per a helicopter pilot's contemporaneous observation). Mountain-side flight in this environment is demanding.
4. Slope-side flying after 7 h aloft: Around 17:00 LT the pilot reports by radio that he is over the San Bernardino at 3,800 m, intending to continue via the Engadin back to Kempten. Probably after about seven hours in the air at high altitude, he operates close to a west-facing slope in the Val d'Agnel.
5. Dehydration and hunger state: No drinks, food remnants or headwear are found in the wreckage. The autopsy notes a marked dehydration with dry mucous membranes, only 50 ml of strongly ketone-positive urine, and an empty stomach — findings consistent with a fitness impairment apt to affect concentration and judgement.
6. Probable loss of control near slope: In the turbulent slope environment, and probably under the effect of fatigue and dehydration, the pilot most likely loses control of the glider at low height above the terrain.
7. Low-speed impact on Corn Alv slope: The DG-400 strikes a rock outcrop on the west slope of Corn Alv at 2,829 m MSL at relatively low forward speed and near-horizontal attitude. Examination of the wreckage finds no pre-existing technical defects; mass and CG were within limits, and the engine was retracted. The aircraft is destroyed and the pilot is fatally injured.