What happened
On July 12, 1967, a L-Spatz glider, registration D-6335, departed from Samedan airfield at approximately 15:40. Initially benefiting from favorable thermal conditions, the pilot successfully navigated toward several peaks, including Piz Bernina and Piz Morteratsch. During the flight, another pilot observed the aircraft flying dangerously close to the terrain and issued two radio warnings, which the pilot acknowledged and briefly addressed.
By late afternoon, the pilot returned to the Schafberg area. However, the upward currents had significantly weakened, making it difficult to maintain altitude. While flying southeast just below the Segantini Hut, the pilot likely experienced a loss of airspeed and perceived a decreasing margin of safety from the ground. In an attempt to correct the flight state and maneuver away from the slope, the aircraft's skid struck a rock ridge in a shallow attitude. The right wingtip also made contact with the ground, causing the wing to detach from the fuselage. The fuselage slid several meters before coming to a halt.
The investigation
The investigation, launched the following day, examined the pilot's experience, the aircraft's condition, and the environmental factors at the time of the accident. The pilot, a German national, had approximately 53 hours of total flight experience, with very limited experience in high-altitude alpine flying. The L-Spatz was found to be in good mechanical condition with no evidence of technical failure. Weather conditions were characterized by light clouds and a Maloj Wind of 5 to 10 knots, with thermal conditions noted as poor by other glider pilots in the area.
Findings
- The primary cause of the accident was the pilot flying at an insufficient distance from the terrain.
- The pilot's lack of experience in alpine environments contributed to the error, as he had previously flown too close to the slope during the same flight.
- Weakening thermal conditions likely prompted the pilot to fly closer to the ridge to exploit remaining lift, increasing the risk.
- A loss of airspeed and local turbulence may have further complicated the pilot's ability to maintain altitude and separation from the ground.
- The visual monotony of the terrain under the prevailing lighting conditions may have made it difficult to accurately judge the distance to the slope.