On January 5, 2005, at 1705 mountain standard time, an experimental single engine Vail Lancair 235, N64BV, impacted flat open desert terrain near Sacaton, Arizona, on the Gila River Indian Reservation. The private pilot/owner operated the airplane under the provisions of 14 CFR Part 91. The airplane was destroyed. The pilot and one passenger were fatally injured. Visual meteorological conditions prevailed for the local area flight that departed Stellar Airpark (P19), Chandler, Arizona, about 1645, and was scheduled to terminate at Stellar Airpark. No flight plan had been filed. According to witnesses interviewed by the Gila River Police Department, they heard an engine cutting out and when they looked up, they saw an airplane in a flat spin, and that it appeared to fall "straight to the ground." The witnesses stated that the airplane was doing "tricks." Another witness reported that he heard the airplane's engine "cutout" and when he looked up the airplane was in a flat spin. He thought the airplane was doing "tricks" as he had seen other airplane's do in the area, but then realized the airplane was not doing tricks. He stated that the airplane started to fall "straight down and doing the flat spin all the way down to the ground." Witnesses at the airport stated that the airplane had last been refueled with 19 gallons of fuel on December 26, 2004, and was not flown until January 5th, the day of the accident. Witnesses reported that the airplane took off, and completed one pass around the airport before departing to the south. A Federal Aviation Administration (FAA) inspector examined the airplane on scene. The airplane came to rest in a muddy area, mostly intact, and on its belly about 500 yards from a small community. The airplane was on a westerly heading, and appeared to have struck the ground in a left wing, nose low attitude. The first identified point of contact (FIPC) was an impression of the left wing, which appeared to be about 4 inches in depth. The airplane came to rest about 3 feet from the FIPC. The rudder separated from the airplane and came to rest 2 feet from the tail section. The flaps, ailerons, and the tail and elevators remained attached to the airplane. Recovery personnel detached the left aileron, right flap, and tail section to aid in the recovery. Investigators examined the airframe and engine at Air Transport, Phoenix, Arizona, on January 14, 2005, under the auspices of the Safety Board. The FAA and Textron Lycoming, a party to the investigation, were present at the inspection. The airframe and engine inspections revealed no preimpact anomalies that would have precluded normal operation. Investigators established flight control continuity from the cockpit to the wings and tail sections. Separations in the flight control tubes appeared jagged in nature. Both flight control sticks separated and were jagged in appearance. The fuel selector handle was in the ON position. The fuel system was continuous, with separations in the lines noted as jagged in appearance. Visual examination of the engine revealed no preimpact anomalies. The Lycoming representative removed the top spark plugs. According to the Champion Aviation Check-A-Plug chart AV-27, the spark plugs exhibited coloration that showed operation in the normal range. He determined that the electrodes were normal to worn out in appearance. Manual rotation of the engine from the crankshaft produced thumb compression in each cylinder in proper firing order. Both magnetos remained connected to their respective mounting pads at the engine. The ignition harness remained attached at the respective magnetos and each spark plug. During manual rotation of the engine, spark was produced at each spark plug lead at the respective magneto. The representative removed and manually rotated the right magneto, producing spark at the points. The Lycoming representative removed the carburetor and fuel strainer, and observed a blue color liquid flowing from their respective fuel lines. He disassembled the carburetor, and the floats were hydraulically crushed in symmetry. The fuel inlet filter screen was free of contamination. The fuel pump remained attached to the engine via its mounting pad. The fuel lines were secured at their respective fittings. An examination of the fuel pump revealed that it was free of internal mechanical malfunction, with no obstructions found. The manufacturer's representative removed the oil filter assembly from the engine, and cut it open. The oil filter was clean of debris.