What happened
On March 7, 2016, a flight training session focused on mountain glacier landings was underway near the Wildhorn Glacier. The flight originated from Geneva, with a planned itinerary including landings on the Wildhorn and Petersgrat glaciers, followed by a stop in Sion and a return to Geneva. The crew consisted of a commercial pilot instructor and a student pilot.
During the session, the instructor performed initial low-level reconnaissance and two landings on a steep slope. The student then completed eight takeoffs and landings following the same tracks. For further training, the instructor directed the student to a new landing site approximately 750 meters east of the Wildhorn summit. After the instructor successfully completed a landing and takeoff at this new location, the student attempted the approach. Although the student's approach trajectory was slightly high, the instructor allowed the maneuver to continue.
As the student attempted to depart the glacier, the right ski of the aircraft struck a rock that had been obscured by snow cover.
The investigation
The investigation focused on the circumstances surrounding the landing gear failure during the takeoff phase. Investigators examined the flight sequence, the training objectives, and the environmental conditions at the Wildhorn Glacier. The inquiry established that the aircraft, a Piper PA-18, sustained damage specifically to the right landing gear leg due to the impact with the hidden obstacle.
Findings
- The primary cause of the incident was the collision between the right ski and a rock hidden beneath the snow.
- The incident occurred during a student-led landing and takeoff maneuver at a new location on the glacier.
- The aircraft, registration HB-PBA, sustained light damage to the right landing gear leg.
- There were no injuries to the crew or passengers during the event.