What happened
While performing cattle herding operations, a helicopter was traveling laterally at approximately 70 feet altitude, out of ground effect, when the pilot heard a loud bang. Following this sound, the pilot attempted to use the anti-torque pedals to realign the aircraft with the flight path; however, the helicopter failed to respond to any pedal inputs.
Although the engine continued to produce high RPM, both the tail rotor and main rotor RPM decreased significantly. In response to the loss of rotor power, the pilot initiated an autorotation. The aircraft touched down on both skids, but due to lateral movement during the touchdown, the helicopter rolled over and came to rest on its side. There were no reported injuries.
The investigation
An inspection of the aircraft revealed that the swedged ball located at the end of the clutch control cable had separated. This mechanical failure allowed the rotor drive system clutch assembly to disengage from the engine power source.