What happened
On October 30, 1971, a Beech Musketeer Sport, registration HB-EWD, departed from Bern-Belp airport for a private VFR sightseeing flight toward the Matterhorn. The aircraft was carrying the pilot and three passengers. Despite warnings from air traffic controllers and flight instructors regarding approaching fog and deteriorating weather, the pilot proceeded with the flight plan.
During the flight, the aircraft transitioned from the Simmental valley into the Diemtigtal region. Witnesses observed the aircraft flying at an alarmingly low altitude. As the aircraft entered the narrow, steeply rising terrain of the Alpetli area, the engine noise was heard to surge briefly before a heavy impact was heard. The aircraft struck the terrain at approximately 15:01, resulting in four fatalities.
The investigation
The investigation examined the aircraft's performance, the pilot's experience, and the meteorological conditions at the time of the accident. Investigators analyzed the wreckage, which showed the aircraft had struck the ground in a left-hand turn. The engine was found to have been producing power at the moment of impact.
Technical analysis of the Beech Musketeer Sport revealed that the aircraft was significantly overweight. The total weight at the time of the accident was approximately 2,342 lbs, exceeding the maximum allowable weight of 2,200 lbs by about 142 lbs. The investigation also reviewed the pilot's flight logs, noting that while he held a valid private pilot license, his experience with this specific aircraft type was very limited, totaling only 4.5 hours.
Findings
- The aircraft was overloaded, which significantly degraded its climb performance.
- The pilot entered the steep terrain of the Allamtal/Alpetli region at an insufficient altitude.
- The aircraft was flying below its minimum required airspeed during a turning maneuver.
- The pilot's lack of experience in mountain flying and with this specific aircraft model contributed to the inability to recognize the developing danger.
- Poor decision-making regarding weather conditions and the decision to proceed despite warnings from professionals led to the inescapable situation.