On March 1, 2003, about 1455 eastern standard time, a Piper PA-28-235, N8547N, was substantially damaged during a collision with trees, while on approach to Westerly State Airport (WST), Westerly, Rhode Island. The certificated private pilot and pilot rated passenger sustained minor injuries. Visual meteorological conditions prevailed, and no flight plan was filed for the local personal flight conducted under 14 CFR Part 91. During an interview with a Federal Aviation Administration (FAA) inspector, the pilot stated that prior to the accident flight, all four fuel tanks were half-full. He and the pilot rated passenger completed five touch-and-go landings to runway 25 at WST, while alternating the flying duties. The pilot initially departed with the fuel selector positioned to the left main fuel tank, and after the third landing, he selected the right main fuel tank. He further stated that the pilot rated passenger was manipulating the controls during the sixth approach. During an interview with a Westerly police officer, the pilot stated that the engine lost power on final approach with the pilot rated passenger at the controls. The pilot attempted to switch fuel tanks and "throttle up," but the airplane struck trees prior to the runway. During an telephone interview with a Safety Board investigator, the pilot stated that during the sixth approach, while on a base leg for runway 25, the engine lost all power. The pilot then took control of the airplane from the pilot rated passenger. The pilot verified the fuel pump was on and switched fuel tanks. He cycled the throttle and ignition, but the engine did not restart. The pilot subsequently performed a forced landing into trees. According to the pilot's written statement, the engine did not respond to throttle input while on final approach, about 1/2 mile from the runway. He applied full throttle, switched from the left main fuel tank to the right main fuel tank, verified the fuel pump was on, and cycled the ignition key. The engine did not restart and the pilot performed a forced landing into trees. During a subsequent telephone interview with a Safety Board investigator, the pilot stated that he could not remember which main fuel tank he switched to after the power loss. He further stated that the tip tanks were not used during the flight, and the fuel selector was always positioned to a main fuel tank. The pilot rated passenger reported to an FAA inspector that while on final approach for the sixth landing, he turned the carburetor heat off and reduced the throttle to idle power. The airplane settled below glidepath, and drifted right of centerline. He attempted to added power, but the engine did not respond. The pilot rated passenger then notified the pilot, and the pilot attempted to restart the engine. The restart attempt included positioning the fuel selector to the left main tank. The pilot rated passenger further stated that his medical certificate had expired, he had no flight experience within the preceding 12 months, and no flight experience in the make and model accident airplane. However, the pilot rated passenger listed 15 hours of pilot in command experience for the make and model accident airplane on an NTSB Pilot/Operator Aircraft Accident Report form. A witness to the accident was in an airplane at WST, holding short of runway 25. He heard the pilot of a Piper report base leg, and did not hear any further transmissions from the pilot. The witness then observed the accident airplane on an approximate 1/2-mile final approach to the runway. The accident airplane appeared to be low, and looked like it was going to land in trees. The propeller was turning, but the witness could not determine engine power or noise. Examination of the wreckage by an FAA inspector did not reveal any pre-impact mechanical malfunctions. The inspector observed the wreckage in a nose down, near vertical attitude, approximately 500 feet from the approach end embankment of runway 25. The left wing tip, including tip tank, had separated from the left wing; and the left wing had separated at the wing root. The left main fuel tank contained residual fuel, and there was a fuel spill in the vicinity of the wreckage. The right wing remained attached to the airframe, and fuel flowed from the right main fuel tank when the fuel cap was removed. One propeller blade was bent aft, and the other was slightly twisted. The mixture and propeller controls were found full forward. The throttle was found about 3/4-inch from the full forward position, and the carburetor heat was off. The fuel selector was found positioned to the left main fuel tank. Examination of the engine by an FAA inspector revealed that fuel was present in the fuel selector and carburetor bowl, and it appeared absent of contamination. The muffler was bent smoothly with no cracks. The inspector was able to confirm crankshaft and camshaft continuity. Review of FAA-H-8083-3, Airplane Flying Handbook, revealed: "The ability to estimate the distance an airplane will glide to a landing is the real basis of all power-off accuracy approaches and landings. This will largely determine the amount of maneuvering that may be done from a given altitude. In addition to the ability to estimate distance, it requires the ability to maintain the proper glide while maneuvering the airplane." The reported weather at WST, at 1453, was: wind from 200 degrees at 8 knots, visibility 10 miles, few clouds at 3,200 feet, overcast ceiling at 5,000 feet, temperature 37 degrees F, dew point 30 degrees F, altimeter 30.23 inches Hg. Review of an FAA Carburetor Icing Probability Chart revealed "Serious Icing at Cruise Power" for the given temperature and dew point.