What happened
A flight instructor was performing an autorotation maneuver that was intended to terminate with power applied. During the procedure, the pilot lowered the collective and reduced the throttle to idle, at which point the engine lost power.
The helicopter touched down heavily in a nose-high attitude on a sod area located between the taxiway and the runway. Upon impact, the main rotor blades struck the tailboom, severing it approximately 24 inches forward of the tail rotor gearbox. Following the contact, the aircraft rotated approximately 160 degrees to the left before coming to an upright stop. There were no injuries reported.
The investigation
An FAA inspector conducted an examination of the engine. An engine run was performed following the incident, and the inspection found no duplication of power loss during the test.