On March 17, 2007 at 0905 central daylight time, a Bell 47G2A, N471KC registered to a previous owner and not registered by the current owner, as a Title 14 Code of Federal Regulation Part 91 personal flight, lost engine power and collided with the ground during an autorotation near Huntsville, Alabama. The helicopter sustained substantial damage and postcrash fire damage. Visual meteorological conditions prevailed at the time of the accident, and no flight plan was filed. The commercial pilot and passenger received minor injuries. The flight originated from the Madison County Executive Airport, Huntsville, Alabama, at 0900. The pilot stated that he had purchased the helicopter 2 days prior to the accident, and did not register it in his name. He said that on the day of the accident he decided to take his friend over to the Moontown Airport, Huntsville, Alabama (3M5), which was a short flight. While enroute to 3M5, he noticed that the main rotor rpm began to decrease. He tried to maintain straight and level flight but the main rotor and engine rpm continued to decrease. He entered an autorotation about 400 feet above ground level, landed hard into soft mud, and nosed over. Shortly thereafter, he and the passenger exited the helicopter, and it burst into flames. According to the previous owner, the helicopter was sold to the pilot for parts. He said that the helicopter was modified and was in an experimental condition. He also said that the pilot told him that once he returned home with the helicopter he would not fly it. Examination of the helicopter by a Federal Aviation Administration (FAA) inspector revealed that the helicopter was not registered to the pilot, and did not display N-numbers in accordance with Federal Aviation Regulation 45.23. According to the FAA inspector, at the time of the accident the helicopter held a current airworthiness certificate. Examination of the helicopter revealed it made a hard landing into a field. A postcrash fire consumed the cabin structure. The airframe and flight control system components revealed no evidence of preimpact mechanical malfunction. Examination of the engine by the FAA inspector and an airframe and powerplant mechanic revealed that both magnetos were melted. All of the spark plugs were removed and contained slight carbon deposits. The cylinders were borescope and no anomalies were noted. A visual inspection of the carburetor revealed that the fuel filter screen was clean and free of debris. The engine was rotated by hand and valve train continuity was established. The examination of the engine and system components did not reveal any evidence of preimpact mechanical malfunction. According to the pilot, the last annual inspection was completed in December 2007, at a recorded tachometer reading of 8,801 hours. He said that the helicopter had flown 64 hours prior to the accident, and that the logbooks were in the helicopter at the time of the crash and were consumed by fire. A review of the helicopter's sales description showed that the engine had 55 flight hours left before a major overhaul. The purchase agreement from the previous owner that was signed by the purchaser revealed that the helicopter was "sold as parts" and noted, "as is."