What happened
On August 11, 1965, a Bell-Agusta 47 J-3 helicopter, registered as HB-XBX, was performing a service flight near Steckhüttenberg, Bern. During the final approach for an external landing, the pilot encountered an unexpected bout of local tailwind. This sudden change in wind direction caused the aircraft to lose lift and drop unexpectedly, resulting in a hard landing on the ground.
The investigation
The investigation focused on the aerodynamic conditions during the final approach and the impact of local meteorological changes on the aircraft's stability. The inquiry established that the sudden onset of the tailwind was the primary factor leading to the loss of altitude and the subsequent heavy impact.
Findings
- The occupants of the helicopter sustained no injuries.
- The aircraft suffered damage estimated at 12 percent of its total value.
- The primary cause of the incident was the unexpected local tailwind encountered during the approach phase.