On March 23, 1994, at 1300 hours Pacific standard time, a Robinson R-22B helicopter, N4081P, landed hard and rolled over during a practice hovering autorotation near Simi Valley, California. The helicopter was being operated by Orbic Helicopters, Inc., Van Nuys, California, as a local instructional flight. The helicopter sustained substantial damage. Neither the commercial pilot/certified flight instructor (CFI), nor the noncertificated student pilot was injured. Visual meteorological conditions prevailed. The flight originated at Van Nuys Airport, Van Nuys, California, at 1230 hours. The CFI stated the student pilot was practicing a hovering autorotation over a level dirt area. The student pilot entered the maneuver between two and three feet above the ground. The student pilot allowed the helicopter to drift left and rearward as the helicopter settled. The heal of the left skid tube caught in the dirt. The student pilot increased the collective control and the helicopter rolled left onto its side. The CFI also stated he did not have time to apply corrective actions before the helicopter rolled over.