Incident Overview
The incident occurred during a lift-off maneuver with an external load. The helicopter was carrying a hopper containing 450 pounds of fertilizer. The operator reported a snapping sound, which was immediately followed by a loss of throttle control from the left collective/throttle control. In response, the pilot switched control hands: the left hand moved to the cyclic, and the right hand took control of the master collective/throttle.
Sequence of Events
Following the loss of throttle control, the pilot initiated an attempted landing. The plan was to set the hopper down first, then land the helicopter. However, during the landing attempt, the right skid of the helicopter contacted the hopper. This contact caused the helicopter to tilt, and as a result, the main rotor struck the ground.
Outcome
The main rotor strike with the ground resulted in the helicopter being pulled approximately 70 feet before it came to rest.