Incident Description
An instructor was performing an autorotation maneuver with a student during a training flight. The entry to the autorotation began at 600 feet in a steady state. The deceleration phase was normal, and upon termination of the maneuver, the instructor felt a small vibration and observed a piece of metal fly over and to the front of the helicopter.
Immediate Actions
In response to the vibration and the sight of the metallic fragment, the instructor immediately closed the throttle and shut down the helicopter. The flight was terminated without further incident.
Post-flight Inspection
After exiting the helicopter, the instructor examined the aircraft and found that the tail section had been damaged. The nature and extent of the damage are consistent with the observed metal piece and vibration.
No further details about the aircraft, occupants, or other circumstances were provided in the source.