On April 29, 1995, at 0858 hours Pacific daylight time, a Robinson R-22 helicopter, N9067B, sustained a hard landing and rolled over on helicopter pad No. 1 at Long Beach Airport, Long Beach, California. The pilot was conducting a local solo visual flight rules instructional flight. The helicopter, registered to and operated by the pilot, sustained substantial damage. The certificated airline transport pilot (fixed wing) was not injured. Visual meteorological conditions prevailed. The flight originated at Long Beach Airport at 0800 hours. The pilot told National Transportation Safety Board investigators in a telephone interview conducted on May 1, 1995, that he was practicing autorotations in preparation for his forthcoming helicopter rating flight test. He said that he initially performed autorotations that terminated with a power recovery. He then began to practice autorotations from a hover to a landing. He said that he planned a run-on landing autorotation, but the helicopter landed hard and bounced. During the recovery, the helicopter rotated to the left and the skids became entangled in the high vegetation (tall grass) which caused the helicopter to roll over. The pilot also said that the helicopter did not experience any preimpact malfunctions or failures. The pilot essentially repeated his statement in the aircraft accident report. He added, however, that on the fourth or fifth autorotation he undershot the helipad and flared the helicopter over the tall grass. He said the tall grass gave him the impression that the helicopter was inches above the ground, but the helicopter was about 3-feet above the ground.