What happened
During a training flight involving a practice helicopter autorotation to a power recovery, the pilot under instruction made an error in timing. The pilot held the flare phase of the maneuver for too long. As a result, the helicopter's tail guard and tail rotor struck the ground. Following the impact, the aircraft began to spin.
The pilot in command (PIC) reduced the throttle to manage the situation. During this sequence, the PIC glanced at the instruments and then looked up to assess the flight attitude. He realized that the attitude was too nose high. The PIC assumed control of the aircraft but did so too late to prevent the impact with the ground.
The investigation
The investigation focused on the mechanical damage sustained by the helicopter following the tail rotor strike. The examination confirmed that the tail guard and tail rotor were damaged due to contact with the ground during the uncontrolled spin phase of the accident sequence.