What happened
On July 25, 1965, a solo glider flight near Pontresina, Switzerland, ended in a fatal accident. The pilot departed from Samedan via winch launch in a D-34-d glider, registration D-4607. After releasing from the winch at approximately 2,150 meters, the pilot proceeded toward the Schafberg mountain.
While performing ridge soaring maneuvers, the pilot flew at a low altitude near the slope. During the flight, the aircraft approached a mast belonging to a high-voltage power line that was under construction. To avoid hitting the structure, the pilot executed a sudden, sharp turn away from the slope. This maneuver caused the aircraft to enter a steep dive, eventually impacting the terrain approximately 60 meters from the mast. The impact resulted in one fatality and the total destruction of the aircraft.
The investigation
The investigation examined the flight conditions, the aircraft's technical state, and the pilot's experience. The D-34-d was a prototype glider with a composite and wood construction. Investigators found that the aircraft's center of gravity was within limits, though positioned toward the forward limit. There were no signs of structural failure or collision with the mast itself prior to the impact.
The pilot, a German national, had approximately 70 hours of total flight experience, but notably lacked experience in mountain flying. While the pilot had been briefed on the presence of the new power line construction by the airfield manager days prior, the specific mast involved was painted in camouflage colors, making it difficult to detect against the landscape.
Findings
- The primary cause of the accident was that the pilot stalled the aircraft while attempting an abrupt evasive maneuver to avoid the power line mast.
- The pilot's lack of mountain flying experience contributed to poor flight tactics, specifically flying too close to the terrain in weak lift conditions.
- The camouflage paint on the power line mast likely hindered the pilot's ability to identify the obstacle in time.
- Seeking to maintain altitude in poor soaring conditions led the pilot to fly at a dangerously low height near the slope.