On December 22, 1996, at about 0940 eastern standard time (EST), a Robinson R-22 helicopter, N8414H, owned and operated by Atlantic Coast Helicopter, struck the ground with the main rotor blades while being hover taxied by a student pilot at the Long Island Macarthur Airport, Islip, New York. The student pilot and certified flight instructor were not injured. The helicopter sustained substantial damage. Visual Meteorological conditions prevailed and no flight plan was filed for the local flight. The instructional flight was conducted under 14 CFR Part 91. The flight instructor stated that the student pilot, who had 13 hours of total flight time, completed the run-up and the pre-takeoff check, and lifted the helicopter into a hover. As they started to hover-taxi forward, the student suddenly applied left cyclic, and the left skid struck the ground. The instructor stated that before he could overpower the student, the helicopter went into a dynamic rollover, and came to rest on its left side, with the engine and rotors stopped. Damage consisted of the main rotors, tail rotor, tail boom and left side of the cabin.