On April 27, 2004, about 1400 Pacific daylight time, a Robinson R22 Beta II, N7521P, experienced a hard landing and rolled over near Squaw Valley, California. Dracor, Inc., was operating the helicopter under the provisions of 14 CFR Part 91. The private pilot and passenger were not injured; the helicopter sustained substantial damage. The local personal flight departed from Truckee, California, about 1350. Visual meteorological conditions prevailed, and a flight plan had not been filed. The wreckage was at 39 degrees 13.24 minutes north latitude and 120 degrees 15.46 minutes west longitude. In a written report, the pilot stated that he departed Truckee to the southwest for a proposed 20-minute tour, with the helicopter's gross weight about 1,240 pounds. While en route at 8,700 feet mean sea level, he noted that the wind was coming from the southeast. He opted to land in an area of flat terrain in an effort to demonstrate an approach to his passenger. During the landing sequence, he slowed the helicopter, and it began to descend. The decent continued and the helicopter landed hard. The helicopter rolled over and the pilot and passenger egressed. After exiting the helicopter, the pilot noted surface wind from the west, which was consistent with a tailwind. The pilot stated that the combination of tailwind conditions and high altitude equated to an undesirable landing environment. He thought that the helicopter's decent rate was too high for the conditions. The pilot reported no preimpact mechanical malfunctions or failures with the helicopter. After the accident the California Highway Patrol helicopter air unit landed at the accident site to determine if the occupants were injured. An officer noted that the elevation at the accident site was 8,359 feet and the outside air temperature was about 71 degrees Fahrenheit. Based on the officer's observations, the density altitude was computed to be about 11,000 feet.