On January 25, 1994 about 1605 hours eastern standard time, a Robinson R-22A, N8559A entered an uncontrolled descent from hovering flight, collided with the runway, and rolled over at Gaithersburg Airport, Gaithersburg, Maryland. The helicopter sustained substantial damage and the certificated private pilot was not injured. The local area instructional flight was being operated by Montgomery Aviation, Limited at the time. Visual meteorological conditions prevailed and a flight plan was not filed. According to an FAA safety inspector, at the time of the accident, the pilot had a private pilot certificate with a single engine airplane rating. The pilot was in the process of being trained to fly helicopters and did not have a helicopter rating. The FAA safety inspector examined the helicopter after the accident and did not find any pre-existing anomalies. In his written statement, the pilot said that during his supervised solo flight, he made his fourth approach to the runway and then began to hover the helicopter. He said the low RPM warning light illuminated and he "...rolled throttle and lowered collective, nose yawed left and gained altitude. Lowered collective (I believe) and left skid touched ground. Bounced on both skids and returned on ground on left skid. Then started dynamic rollover." Neither the pilot nor the operator reported any pre-existing deficiencies for the helicopter prior to the accident.