On August 4, 2004, approximately 1430 mountain daylight time, a Mooney M20R, N4157, piloted by a commercial pilot, sustained substantial damage during a hard landing at Aspen-Pitkin County/Sardy Field (ASE), Aspen, Colorado. Visual meteorological conditions prevailed at the time of the accident. The cross-country sales demonstration flight was being conducted under the provisions of Title 14 CFR Part 91 with a visual flight rules flight plan. The pilot and flight instructor on board the airplane were not injured. The flight originated at San Angelo, Texas, approximately 1300 central daylight time. The following is based on the accident report filed by the flight instructor. He stated that he was asked to give a sales demonstration flight to a potential customer. He was told the customer was "an experienced pilot" who often flew his Cessna P210 to Aspen, and wanted to fly the Mooney M20R. The instructor said the customer (hereinafter referred to as the pilot) "was fully aware that I was an instructor and that he would relinquish control of the aircraft at any time that I stated that it was my aircraft." The flight was uneventful. As they approached Aspen, they were advised that the wind was from 330 degrees at 10 knots, gusts to 15 knots, and low-level wind shear. They extended their downwind leg and made a 360-degree turn to lose altitude. When they turned onto the final approach to runway 15, the PAPI (precision approach path indicator) lights indicated a "normal Mooney approach": descent rate was 400 feet per minute, and indicated airspeed was 90 knots. Due to the tail wind, they crossed the runway threshold "a little high" and fast. About 12 feet above the runway, the pilot raised the aircraft nose to flare for landing. Airspeed dropped rapidly and the instructor told the pilot to relinquish aircraft control. The pilot continued to raise the nose and the stall warning horn sounded. As the pilot held the nose high attitude, the instructor applied full power "to keep the nose from falling over from the impending stall." The airplane then impacted the runway. The pilot's accident report corroborated that of the flight instructor's, only he said the wind was 10 to 15 knots from the southeast. "Over the threshold, [the instructor] said we were too high and began pushing the control yoke forward. I interpreted his control inputs as help to [aid] me [in] landing. Simultaneously I began pulling back on the yoke to flare the plane for landing." The tail struck the runway and the airplane bounced, then the propeller struck the runway, stopping the engine. The airplane coasted off the runway onto a taxiway.