Incident Overview
A helicopter experienced a hard landing at the conclusion of a practice autorotation during an instructional flight lesson. The certified flight instructor (CFI) was monitoring the student pilot's flying. The student had approximately 15 hours of total helicopter flying experience.
Sequence of Events
According to the CFI, the student initiated the landing flare about 40 feet above ground level (agl). When the helicopter descended to about 10 feet agl, the CFI took over the controls, raised the collective, and rolled on the throttle to initiate a power recovery. During this maneuver, the helicopter's low rotor warning horn sounded and the respective annunciator light illuminated.
Subsequently, the helicopter contacted the ground, bounced, and then came to rest after making two complete rotations about its vertical axis.
Damage
The tailboom and vertical stabilizer were bent during the ground impact sequence.
No Mechanical Issues
No mechanical malfunction or failure was reported to have occurred.