On June 10, 2003, about 1845 mountain standard time, a Robinson R-22 Beta, N7508D, landed hard and rolled over during a power recovery from a practice autorotation near Deer Valley Airport (DVT), Phoenix, Arizona. Quantum Helicopter, Inc., was operating the helicopter under the provisions of 14 CFR Part 91. The certified flight instructor (CFI) and student sustained minor injuries; the airplane sustained substantial damage. The local instructional flight departed Scottsdale Airport (SDL), Scottsdale, Arizona, about 1730. Day visual meteorological conditions prevailed, and no flight plan had been filed. The CFI stated that he and the student experienced a "total rotor stall" due to a failure to do a power recovery. He and the student had performed a series of autorotations prior to the eventful one. The entry and glide were "very well managed, the student nailed his rpm control and pitch in the glide." During the level off from the flare, the student was beginning to raise the collective as power was restored. The CFI told the student to begin rolling on the throttle, simultaneously reaching for the throttle himself to assist the student in rolling it on. However, the student firmly gripped the throttle and rolled it off. The instructor reported that he could not override the student's input prior to a main rotor rpm decay that caused the helicopter to land hard. Due to gusty wind conditions, the helicopter was blown off course and came to rest on its left side in a mature cactus (cholla) bed. The Federal Aviation Administration inspector examined the helicopter. Flight and throttle control continuity was established and no preimpact anomalies were found.