What happened
On July 22, 1975, a Cessna 150 K, registration HB-CVO, departed Zurich airport for Speck-Fehraltorf to conduct landing training. During the approach to runway 31, the aircraft's glide path became too high. In response, the instructor instructed the student pilot to apply full flaps and reduce power. This maneuver resulted in an abrupt leveling off, causing the aircraft to drop at a rate of approximately 5 m/s.
As the stall warning activated, the instructor intervened by applying power and reducing back pressure on the controls. During this moment, the student pilot released control of the yoke and throttle. The aircraft subsequently dropped, striking the ground 150 to 200 meters past the runway threshold at a high angle of attack.
Attempting to execute a go-around, the instructor applied full power and tried to steer the HB-CVO back toward the runway centerline. However, the aircraft remained in a high-pitch attitude with full flaps extended, causing it to veer approximately 40 degrees left of the centerline toward a gravel pit. The main landing gear intermittently struck the ground before the aircraft slid into a three-meter-deep ditch, coming to rest upside down and rotated 180 degrees. There were no injuries to the two occupants, but the aircraft was destroyed.
The investigation
The investigation examined the flight experience of both occupants, the airworthiness of the aircraft, and the environmental conditions. The instructor held a valid commercial pilot license with various ratings, while the student pilot was operating under a valid training permit. The aircraft was found to be airworthy, with its weight and center of gravity within permissible limits. Weather conditions at the time included visibility of 30-40 km and a light westerly wind.
Findings
- The primary cause of the accident was an incorrect go-around procedure following a failed landing.
- The student pilot's decision to release the controls was identified as a common novice reaction to an error.
- The instructor's intervention following the high approach was not sufficiently decisive, leading to the aircraft's drop.
- The instructor failed to reduce engine power to idle and failed to lower the nose wheel after the initial hard impact, which would have allowed for effective nose-wheel steering to correct the veer.
- The go-around attempt failed because the low-powered aircraft could not regain sufficient airspeed while maintaining a high angle of attack with full flaps extended.