Accident Sequence
The flight was a night operation involving a commercial helicopter. The pilot terminated the approach to a hover at an altitude of 6 to 8 feet. The hover position had trees and two post-boxes to the right, and a large ditch to the left. The pilot initiated a sideways left hover to move away from the trees. Subsequently, he began a left pedal turn to orient the helicopter toward emergency medical services (EMS) units positioned behind the aircraft.
After turning approximately 120 degrees, the pilot reported moving backwards, and the tail rotor struck trees. The pilot immediately stopped the turn and moved the helicopter forward. However, tail rotor control was lost. As the helicopter began to spin, the pilot lowered the collective and executed a hard landing.
Damage
Examination of the helicopter revealed that the tail rotor drive shaft forward of the 45-degree gearbox was sheared.