What happened
On July 4, 1970, at approximately 12:09 PM, a Bölkow-207 aircraft, registration HB-UXR, departed from runway 28 at Zurich Airport. The flight was a private mission destined for Munich, carrying the pilot and three passengers. Following takeoff, the pilot initiated a climbing right turn as instructed by the tower. Witnesses observed the aircraft leveling off at an altitude of roughly 20 meters before entering the turn. During this maneuver, the aircraft appeared to be flying at a low speed. After completing a turn of slightly more than 90 degrees, the aircraft suddenly banked sharply to the right, entering a near-vertical attitude at an altitude of only 30 to 50 meters. The aircraft struck the ground approximately 1,000 meters northwest of the runway threshold in a marshy area.
The investigation
The investigation examined the aircraft's mechanical condition, the pilot's experience, and the environmental factors at the time of the accident. The Bölkow-207 was found to be airworthy, with its weight and center of gravity within permissible limits. Examination of the engine and propeller revealed that the motor was operating at high power at the moment of impact. Investigators also noted that the landing flaps were extended to 22 degrees, which exceeded the recommended 15 degrees for the flight phase. The pilot's medical records and toxicology reports showed no impairments, and his flight training on this specific model had been completed recently in May 1970.
Findings
- The primary cause of the accident was that the aircraft fell below its minimum flying speed during the climbing turn.
- The pilot executed a relatively tight and rapid turn at a low altitude, which was not required by air traffic control or the prevailing traffic situation.
- The aircraft's center of gravity was positioned toward the rear of the allowable range, which likely contributed to the loss of control.
- Light turbulence in the area may have further exacerbated the stall conditions.
- Due to the extremely low altitude, the pilot was unable to recover the aircraft before impact.
Safety action
No specific safety recommendations were recorded in the final report.