What happened
On July 26, 1971, a Ka 6 CR glider, registration HB-808, departed from Bern-Belp airport for a training flight. The flight, which was initially conducted via a tow operation, proceeded over Zimmerwald, Riggisberg, and Gurnigel toward the Gantrisch region. While cruising at approximately 2,000 meters, the aircraft began to lose altitude.
Seeking to return to the departure point via the Selibühl Pass, the pilot found insufficient upward lift and lacked the necessary altitude to clear the pass. After attempting to find rising air by turning westward, the pilot decided to perform an outlanding near Zollhaus at an altitude of roughly 400 meters. The approach was flown downslope into a tailwind. During the landing pattern, the aircraft drifted past a small embankment, at which point the pilot noted a sinking rate of 3 meters per second on the variometer. This unexpected descent caused the aircraft to fall short of the intended landing spot. The glider touched down with a slight skid at approximately 15:45, resulting in a ground loop. The pilot sustained no injuries, but the aircraft suffered heavy damage.
The investigation
The investigation confirmed that the pilot held a valid glider license with passenger authorization and possessed 94 hours and 37 minutes of total flight experience. There was no evidence of medical impairment or health issues affecting the pilot's performance. The aircraft was found to be airworthy, with its weight and center of gravity within prescribed limits, and no pre-existing technical defects were identified as contributing to the event.
Meteorological data indicated 3/8 cloud cover with a base of 2,500 meters and visibility exceeding 20 km. Winds were recorded from the west at 5-10 knots, though local conditions at the site were reported as calm and warm.
Findings
- The pilot initiated the final approach with insufficient altitude reserve.
- An unexpected sink rate of 3 m/s prevented the pilot from compensating for the loss of height during the approach.