What happened
On April 26, 1960, a flight instructor and a student were conducting off-airport training landings in the Misox region near Lostallo, Switzerland. After performing an initial landing on a field, the crew attempted a second takeoff from the same location. During the climb, the Piper J3C encountered a tailwind and was operating above its maximum allowable weight. Approximately 1,100 meters into the takeoff roll, at an altitude of roughly 40 meters, the aircraft entered a slight left turn. During this maneuver, the aircraft struck the cable of a transport cableway. The impact severed the right wing and ignited the escaping fuel, causing the aircraft to crash into a wooded area. The accident resulted in two fatalities.
The investigation
The investigation examined the operational conditions, the aircraft's technical state, and the pilot's preparation. It was established that the aircraft, registration HB-ONL, had recently undergone an undocumented engine change from a 90 HP motor to a 65 HP motor, which reduced the maximum permissible weight. At the time of the accident, the aircraft's weight was approximately 570 kg, exceeding the 550 kg limit applicable to the 65 HP configuration. The investigation also noted that the landing site was located in a zone marked on aeronautical charts as having numerous obstacles, specifically including the cable car lines. Furthermore, the instructor had not briefed the student on these specific hazards or performed a recent reconnaissance of the field.
Findings
- The primary cause of the accident was the inadequate adjustment of the flight path during the takeoff climb to avoid known obstacles.
- The flight instructor failed to sufficiently prepare for the off-airport landings, specifically regarding the identification of hazards in the terrain.
- A tailwind and the aircraft's overweight condition contributed to an extended takeoff roll, making the necessary turn away from the obstacles more difficult.
- The pilot was aware of the obstacles in the area but failed to implement a flight path that moved the aircraft away from the slopes and cables immediately after takeoff.