What happened
On May 7, 2013, a Pilatus PC-6, registration HB-FKT, was conducting a training flight involving an instructor and a student. The mission involved transporting passengers and supplies to the Trient Glacier for a group event. After an initial flight to the airfield at Bex to drop off passengers and equipment, the crew returned to the glacier.
Upon returning to the glacier, the crew encountered diffuse lighting caused by high cloud cover. The instructor attempted the landing, but because the aircraft could not be brought to a complete stop without using reverse thrust, a second approach was initiated. During this second attempt, the lack of visual references became problematic. The instructor requested the student to monitor the aircraft's altitude, but a stall occurred at a low altitude. The aircraft struck the ground with significant force, causing structural damage to the fuselage and windshield frame.
Following the impact, the instructor decided to fly the damaged aircraft back to Bex with the student and five passengers on board. The remaining five people on the glacier were later evacuated via helicopter.
The investigation
The Swiss investigation established that the aircraft was in a valid condition for VFR and IFR operations and found no mechanical defects contributing to the accident. The investigation noted that the aircraft's emergency beacon failed to activate upon impact.
Investigators also examined the crew's decision-making. They found that the instructor's decision to attempt the landing despite marginal visibility increased operational risk. Furthermore, the decision to fly the damaged aircraft back to Bex was deemed inadequate, as the crew lacked the expertise to assess the structural integrity of the airframe, and an alternative evacuation method should have been organized for the passengers left on the glacier.