What happened
On December 18, 2021, at approximately 16:10 local time, a McDonnell Douglas 50-series 500N helicopter, registration HB-ZBM, was involved in an accident in Unteriberg, Switzerland. The aircraft, operated by Fuchs Helikopter, was performing a private flight under Visual Flight Rules (VFR). The flight originated from a field landing site in Eischen and was destined for the heliport in Schindellegi.
During the landing sequence, the pilot performed an autorotation. As the aircraft reached the ground, the helicopter rolled over to the left side.
The investigation
The Swiss Transportation Safety Investigation Board (SUST) examined the circumstances surrounding the landing. The investigation focused on the aircraft's behavior during the final stages of the autorotative descent and the subsequent touchdown at the landing site.
Findings
- The aircraft sustained serious damage as a result of the impact.
- The landing site experienced minor ground damage caused by a small amount of spilled fluids from the helicopter.
- The primary factor in the accident was the leftward rollover that occurred immediately upon touchdown during the autorotation maneuver.