What happened
On November 12, 2022, a Robinson R22 Beta II, registration HB-ZOF, was conducting a training flight for a student pilot to obtain a mountain flying rating. The flight, operated by Valair AG, began at Balzers Heliport under Visual Flight Rules (VFR). The crew, consisting of a flight instructor and a student, had been performing several training approaches at various locations throughout the day.
Upon reaching the Vorder Alp area, the instructor selected a landing site on a steep, 45-degree slope at an elevation of approximately 1,890 meters. After several successful approaches and landings at this site, the crew prepared for a departure. During the transition from a hover into forward flight, the crew noticed a slight reduction in rotor RPM. The instructor took control and attempted to stabilize the RPM by reducing the collective pitch. However, as the aircraft was already over steeply descending terrain, a safe landing was no longer possible. The instructor attempted to accelerate the helicopter parallel to the slope to gain translational lift, but the skids struck the ground, causing the helicopter to overturn. The aircraft was destroyed, though both occupants escaped without injury.
The investigation
SUST examined the technical condition of the Robinson R22 Beta II, the flight preparations, and the crew's actions. The investigation confirmed that the aircraft's weight and center of gravity were within permissible limits and no mechanical defects were found. Investigators focused on the performance capabilities of the engine at high altitude and the configuration of the carburetor heat control. The investigation also reviewed the flight instructor's experience level and the specific challenges posed by the chosen landing site.