Incident Overview
A helicopter flight instructor and an airplane-rated student pilot were conducting an autorotation maneuver with a 180-degree turn and power recovery. The instructor reduced the throttle to idle while abeam the departure end of the runway. The student overshot the runway and aligned with a parallel taxiway. The decision was made to abort the maneuver and initiate a go-around.
Sequence of Events
During the go-around, while the student pilot was flying, the instructor inadvertently manipulated the throttle. The throttle was moved from idle, aft toward the off position, and then forward to the fly position. This resulted in a total loss of engine power. The instructor attempted to adjust the throttle but was unsuccessful. As the helicopter descended, the student requested that the instructor take control. The instructor left the throttle at full power and performed a power-off autorotation landing. The helicopter touched down on the taxiway and skidded approximately 180 feet. It continued off the taxiway onto adjacent grass before coming to rest in a drainage ditch.
Aftermath
The flight instructor reported that no preaccident mechanical failures or malfunctions were present. An FAA inspector examined the helicopter and documented damage to the left anti-vibrator mount beam.