On March 2, 1994, at 1450 Pacific standard time, a Hughes 269C, N9593F, sustained substantial damage during a practice autorotation at Merced, California. The helicopter was owned and operated by Moore Helicopter Services, Inc., of Stockton, California, and was on a local area Federal Aviation Administration (FAA) flight test conducted under 14 CFR Part 91. Visual meteorological conditions prevailed at the time and no flight plan had been filed for the operation. The certificated commercial pilot/CFI applicant and the FAA operations inspector on board received minor injuries. The flight originated on the day of the mishap at about 0930 from the Stockton Metro airport. In a verbal statement, the FAA operations inspector on board the accident helicopter reported that he had directed the pilot to perform a practice autorotation with a 180-degree turn, terminating with a power recovery to approximately a three-foot hover. The inspector told the pilot to plan for a termination point identified by the "x" on a closed runway that intersected with runway 30, the active runway at the time of the maneuver. The pilot entered the autorotation while downwind at 650 feet above ground level (agl) for the closed runway abeam the planned point of termination by lowering the collective and rolling off the throttle. The needles split, the rotor rpm was in the green, and the engine rpm stabilized at 2,000. The maneuver progressed normally, although the inspector had noted that the helicopter was apparently going to overshoot the planned termination point. At 200 feet agl, the pilot announced to the inspector that he was going to overshoot his planned touchdown point. The inspector said the pilot had begun deceleration at about 50 feet agl and was beginning to settle while in a slightly nose- high attitude. The inspector noticed that the pilot had gone through his deceleration and he had not heard the engine rpm increase. At that point, the inspector took the controls and attempted to roll on the throttle so as to apply enough collective to cushion the impact; however, in spite of his efforts, the helicopter continued to settle. The helicopter touched down hard on soft, muddy ground about 100 feet beyond the planned termination point with about 10 knots forward airspeed. The helicopter bounced once, pitched forward, and then impacted a second time. The helicopter rolled tail over nose and came to rest on its right side. A postaccident inspection conducted by FAA airworthiness inspectors failed to identify any discrepancies related to the helicopter's engine or power controls.