HISTORY OF FLIGHTOn October 18, 2014, about 1230 mountain standard time, a Piper PA28-151, N56873, landed off-airport following a partial loss of engine power during the initial climb from Sun Valley Airport near Bullhead City, Arizona. The pilot/owner was operating the airplane under the provisions of 14 Code of Federal Regulations (CFR) Part 91. The private pilot and one passenger sustained minor injuries. The fuselage sustained substantial damage during the accident sequence. The cross-country personal flight was departing with a planned destination of Henderson, Nevada. Visual meteorological conditions prevailed, and no flight plan had been filed. The pilot was returning to her home airport after a cross-country flight. After takeoff and during the initial climb, she felt that the airplane seemed heavy as if the engine was not generating full power. She thought that the airplane was about 500 feet above ground level (agl) when the stall alarm started sounding. She pushed the flight controls forward, and pointed the nose down to go under power lines that were in her immediate flight path. The airplane landed in uneven desert terrain, and an engine fire began. The pilot and passenger evacuated safely. A witness at the airport stated that he saw/heard the airplane during takeoff, and thought that the engine was not making full power. He estimated that the airplane reached about 50 feet agl, and then made a steep left turn before vanishing out of site. AIRCRAFT INFORMATIONThe airplane was a Piper PA28-151, serial number 28-7415021. A review of the airplane's logbooks revealed that the airplane had a total airframe time of 5,407 hours at the most recent annual inspection dated April 10, 2014. The engine was a Lycoming O-320-E3D, serial number L-35763-27A, rated for 150 horsepower at 2,700 rpm. The time since major overhaul recorded on the engine at the most recent annual inspection was 3,438 hours. METEOROLOGICAL INFORMATIONAn automated surface weather observation at Laughlin/Bullhead (IFP), Bullhead, Arizona (elevation 701 feet msl, 9 miles north of accident site) was issued 5 minutes after the accident. It indicated wind from 350 degrees at 13 knots, 10 miles or greater visibility, clear sky, temperature at 31 degrees C, dew point 06 degrees C, and an altimeter setting at 29.83 inches of mercury. AIRPORT INFORMATIONThe airplane was a Piper PA28-151, serial number 28-7415021. A review of the airplane's logbooks revealed that the airplane had a total airframe time of 5,407 hours at the most recent annual inspection dated April 10, 2014. The engine was a Lycoming O-320-E3D, serial number L-35763-27A, rated for 150 horsepower at 2,700 rpm. The time since major overhaul recorded on the engine at the most recent annual inspection was 3,438 hours. ADDITIONAL INFORMATIONThe pilot did not submit the NTSB Pilot/Operator Aircraft Accident/Incident Form 6120.1. TESTS AND RESEARCHInvestigators from the National Transportation Safety Board, Federal Aviation Administration, and Lycoming Engines examined the wreckage at Air Transport, Phoenix, Arizona, on October 27, 2014. A complete examination report is contained within the public docket for this accident. The airframe and engine were examined with no mechanical anomalies identified. The airframe and engine had been partially consumed by a fire. Airframe The fuel selector valve was in the LEFT position. The gascolator contained a clear blue fluid that smelled like aviation gasoline; the screen was clean. Engine The rear portion of the engine was heavily charred; the right rear of the engine had the most thermal damage while the left front had the least thermal damage. There were no holes in the crankcase or cylinders that indicated a catastrophic failure of the engine. The crankshaft was manually rotated with a tool in an accessory drive gear. The crankshaft rotated freely, and the valves moved approximately the same amount of lift in the proper firing order. The fuel pump plunger moved up and down, and the gears in the accessory case turned freely. Thumb compression was obtained on all cylinders. The top spark plugs were removed; all center electrodes were circular and clean with no mechanical deformation. The spark plug electrodes were gray, which corresponded to normal operation according to the Champion Aviation Check-A-Plug AV-27 Chart. A borescope inspection revealed no mechanical deformation on the valves, cylinder walls, or internal cylinder head. The magnetos were manually rotated, and both magnetos produced spark at all posts. The carburetor and induction system including the air filter exhibited thermal damage. The carburetor was dissembled. The floats were metal; the solder line on one was shiny, but they were otherwise unremarkable. The bowl contained no fluid. Propeller The propeller blades were bent and twisted in the direction opposite normal rotation. Both blades exhibited leading edge gouges and chordwise striations.