What happened
On August 5, 1973, a Ka-7 glider, registration HB-1077, departed from the Schaffhausen-Neunkirch airfield for a soaring flight. The aircraft was carrying the pilot and one experienced passenger. After approximately one hour of flight, the pilot encountered a lack of rising air currents and utilized an unsuitable flight strategy, resulting in a significant loss of altitude.
As the aircraft's height became insufficient to return to the home airfield, the pilot attempted to locate updrafts but was unsuccessful. Consequently, a decision was made to perform an off-field landing in a meadow on the Rüetisberg near Schleitheim. During the approach, which was conducted at a very low altitude, the left wingtip struck the ground. This impact caused the glider to veer sharply to the left, ultimately coming to rest in a barley field approximately 90 meters short of the intended landing site. The impact resulted in one minor injury to the pilot, while the passenger remained unharmed. The glider was destroyed.
The investigation
The investigation established that the pilot was medically fit and possessed sufficient flight experience, including specific training on the aircraft type. The aircraft itself was found to be airworthy, with no pre-existing technical defects identified. Weather conditions at the time of the accident were favorable, characterized by good visibility and light winds.
Investigators determined that the aircraft had been flying at an extremely low altitude for approximately ten minutes prior to the landing attempt. The investigation also noted that the pilot attempted a steep landing pattern to land into the wind, following a suggestion from the passenger.
Findings
- The pilot failed to account for lee-side effects, which contributed to the loss of altitude.
- The decision to execute an off-field landing was made too late, after the aircraft had already been flying at low altitude for an extended period.
- The primary cause of the impact was either descending below the minimum flying speed or an error in estimating the aircraft's height during a steep maneuver performed very close to the ground.