What happened
On April 30, 1967, a training flight involving a Schempp-Hirth SHK 1 glider, registration HB-856, ended in a fatal-impact accident on the Schäniserberg in Switzerland. After approximately three hours of soaring in thermal conditions, the pilot attempted to maintain altitude using weak ridge lift along the northwest slope of the mountain.
While executing a left-hand turn with a 45-degree bank, the aircraft's airspeed dropped below the required minimum. This loss of speed caused the glider to enter a spin. Although the pilot briefly managed to arrest the rotation by applying full opposite rudder, a subsequent attempt to steer away from the approaching terrain via right aileron input triggered a second left-hand spin. The aircraft completed three full rotations before striking a wooded slope, resulting in a total loss of the airframe. The pilot sustained severe injuries, including multiple fractures.
The investigation
The investigation examined the aircraft's flight parameters, the pilot's experience, and the technical specifications of the HB-856. Investigators reviewed the aircraft's weight and balance, confirming that the center of gravity and total weight were within the permitted limits at the time of the accident.
Technical analysis focused on the minimum flight speeds required for safe maneuvering. The investigation also reviewed the pilot's recovery attempts and the use of the braking parachute. It was noted that the pilot had very limited experience with this specific model, having flown it only three times for a total of approximately five hours.