Primary finding
Probable cause
The pilot's selection of unsuitable terrain for landing, which resulted in a tailrotor strike.
Investigator assessment
Analysis narrative
The pilot flew to a practice area and landed the helicopter on what the pilot thought was firm snow. As he landed, the helicopter suddenly broke through the surface and its tailrotor struck the snow. The pilot repositioned the helicopter and the tailrotor gearbox chip detector light illuminated. An examination showed that the tailrotor driveshaft had sheared.
Source record
Factual narrative
The pilot flew to a practice area and landed the helicopter on what the pilot thought was firm snow. As he landed, the helicopter suddenly broke through the surface, and its tailrotor struck the snow. The pilot repositioned the helicopter, and the tailrotor chip light illuminated. An inspection showed that the tailrotor driveshaft had sheared.