What happened
On July 5, 1972, a Ka-8B glider, registration HB-701, was performing a solo training flight near Saanen, Switzerland. The pilot had previously completed an instructional flight with an instructor on the same day. Following an initial period of flight in good conditions, weather conditions deteriorated significantly. Around 13:30, while flying at an altitude of approximately 2,300 meters, the pilot observed other gliders returning to the Saanen airfield and decided to terminate the flight.
As the pilot began a descent toward the airfield with airbrake flaps extended, the aircraft encountered heavy rain and intense turbulence. While maneuvering toward runway 26, the pilot struggled with the gusty winds. During the descent, the tail of the aircraft struck the overhead power lines of the Montreux-Oberland Railway (MOB). The glider subsequently became caught in the treetops approximately 3 meters above the ground, south of the Saende Saanen station.
The investigation
The investigation confirmed that the pilot held a valid glider license, though they had relatively limited flight experience, totaling approximately 25 hours of total flight time, with only 8 hours specifically on this aircraft type. There were no indications of medical issues affecting the pilot's performance. The aircraft, HB-701, was found to be airworthy and within weight and balance limits, with no pre-existing technical defects identified.
Meteorological data indicated that a thunderstorm zone was moving into the region, bringing heavy cloud cover and significant wind fluctuations. At the time of the accident, winds at 3,000 meters were reported at 30 knots from the south, characterized by strong gusts and instability.
Findings
- The primary cause of the accident was a collision with obstacles (overhead power lines).
- The pilot's limited experience in alpine soaring contributed to the difficulty in managing the aircraft during the weather deterioration.
- The intense turbulence and gusty conditions distracted the pilot, leading to the failure to retract the airbrake flaps during the descent.