Flight Details
The purpose of the flight was to conduct pattern work, including takeoffs and landings, to prepare a private pilot for his commercial pilot practical test. The private pilot was on the flight controls while a certified flight instructor (CFI) monitored. The first two takeoffs and landings were completed without noted discrepancies.
Autorotation Training
During the first autorotation, the CFI observed that the student allowed the airspeed to drop below 60 knots and the rotor rpm moved outside the top of the green arc. The CFI instructed the student to maintain 65 knots airspeed until near the ground and to raise the collective to keep rotor rpm within the green arc. On the second autorotation, the student maintained rotor rpm within the green arc but let airspeed fall below 58 knots. The low rotor rpm warning horn sounded and the caution light illuminated.
Hard Landing and Aftermath
Due to the helicopter's close proximity to the ground, a flare for landing was initiated. The CFI took over the controls and noted the collective was higher than normal. Before touchdown, the CFI applied forward cyclic to maintain a level attitude after touchdown. The helicopter landed hard and slid across the ground before coming to rest in a grassy area next to the helipad. After stopping, the CFI attempted to move the anti-torque pedals but received no response. The tail boom was severed.
No further details were provided in the source regarding injuries, damage extent, or subsequent actions.