What happened
On June 24, 1961, a Bücker 131 aircraft, registration HB-URG, was engaged in a recreational flight near Rolle, Switzerland. The pilot, returning from a flight to Bern, decided to perform a low-altitude pass over the Le Rosey Institute, a location where they had previously stayed.
After observing students watching from the ground, the pilot executed a right-hand turn at a very low altitude, estimated by witnesses to be between 5 and 20 meters. During a subsequent steep climb, the aircraft entered a spin at an altitude of approximately 250 meters. Although the pilot managed to stop the rotation after roughly two and a half turns, the aircraft lacked sufficient altitude to recover from the descent, leading to a collision with a rye field at 12:05.
The investigation
The investigation examined the pilot's experience, the aircraft's mechanical condition, and the sequence of maneuvers. The pilot held a special permit for aerobatic flight and had 450 total flight hours, with 15 hours specifically on the Bücker 131. The aircraft was found to be in good airworthy condition, with its center of gravity within limits and no mechanical defects noted. Investigators also reviewed photographic evidence of the accident, which captured the aircraft's descent.
Findings
- The primary cause was the pilot's decision to perform maneuvers at an extremely low altitude.
- The spin was triggered when the pilot, distracted by observing spectators on the ground, failed to monitor airspeed during a climb.
- It is believed that while looking back and to the right, the pilot unintentionally applied left rudder, inducing a lateral stall and spin.
- Analysis of photographs indicated a delayed recovery response, as the pilot did not take corrective action to stop the rotation during the first or second turn.
- The pilot's sudden loss of control likely caused a momentary lapse in situational awareness, resulting in the loss of critical seconds needed for recovery.
Safety action
No specific safety recommendations were recorded in the final report.