20011125031789A

(-23) During auto rotation to ground, instructor pilot noticed aircraft descending too rapidly but could not recover in time. (.4) on November 25, 2001, about 1600 central standard time, a Hughes OH-6A helicopter, N129BC, registered to, and operated by the desoto county sheriff's office, as title 14 CFR part 91 instructional flight, made a hard landing at a Private field in Hernando, Mississippi. Visual meteorological conditions prevailed, and no flight plan was filed. The student pilot, and the airline transport-rated flight instructor were not injured, and the helicopter incurred substantial damage. The flight originated from Hernando, Mississippi, the same day, about 1610. The flight instructor stated that they had been practicing autorotations and during the last autorotation the student was flying the helicopter. The instructor said that the airspeed on final was 70 knots, and that the student flared the helicopter at an altitude of about 65 feet, and applied initial collective pitch control input at about 10 feet, leveling the helicopter. He said that the helicopter was about 2 feet high, and still moving forward, and at that point the student did not let the helicopter settle to the ground, but continued to apply collective pitch control input. The instructor said he stopped the student from applying collective pitch control input, and the helicopter started to descend, but the student applied aft cyclic control input, and the helicopter contacted the ground on the heels of the skids, while main rotor rpms were low. He said the main rotor blades contacted the tail boom, severing the tail just forward of the tail rotor gear box. According to the flight instructor, prior to the accident, there were no failures or malfunctions to the helicopter, or any of its systems.