20040719014569A

(-23) The purpose of the flight was to demonstrate the aircraft to the local sheriffs department. The pilot in command, a certificated helicopter flight instructor, loaded the helicopter to its maximum allowable gross weight at the rialto airport in preparation for a demonstration flight to the nearby mountains. The rialto airport is 1455 feet MSL. The highest elevation in the local flying area is 11,499 feet MSL. The purpose of the flight was to demonstrate the aircraft's mountain flying capabilities at high gross weights. The PIC determined from the performance charts that the aircraft was not capable of out-of-ground effect hover at the weight and density altitudes expected during that portion of the flight conducted in the higher elevations. The PIC did not plan to conduct maneuvers that required out-of-ground effect hover capabilities. The PIC did not adequately brief the other pilot of the planned maneuvers. The pilot allowed a passenger, a certificated helicopter pilot with the sheriffs department, to fly the aircraft up a canyon into the local mountains. The flight in the mountains was conducted at about 50 feet above the terrain and trees. At an elevation of approximately 8,800 feet (12,500 ft da) the pilot flying started reducing the airspeed from about 60 knots to below 20 knots, while increasing power. The rotor RPM started to decay, and the low rotor RPM voice warning system activated. The pilot flying started a left pedal turn, as the aircraft continued its descent. The PIC tried to take the controls to start a right turn toward an open area to the right of the aircraft. The PIC stated that the other pilot did not completely relinquish the controls and both pilots were on the controls at once until just before impact. The rotor RPM decayed to the point that the aircraft could not sustain flight. The aircraft landed hard in a small sloping open area, causing substantial damage to the aircraft. There were no injuries.