On May 26, 2003, about 1200 eastern daylight time, a Cessna 172E, N817T, registered to a private individual, collided with terrain shortly after becoming airborne from Earle Airpark, Hastings, Florida. Visual meteorological conditions prevailed at the time and flight plan information is unknown. The airplane was substantially damaged and the commercial-rated pilot and pilot-rated passenger were not injured. The flight was originating at the time of the accident. The pilot stated that he installed the transponder and was taxiing to check whether it was operative. While taxiing, he lost directional control of the airplane and after observing a ditch, he applied power to clear the ditch. The airplane cleared the ditch and he then reduced power and the airplane descended and came to rest in brush. As a result of the landing in brush, damage to the airplane consisted of the shearing of the right main landing gear. Additionally, skin inboard of the right main landing gear was damaged. The airplane was dropped during recovery causing additional damage. The pilot did not initially advise the NTSB there was a passenger on board the airplane. The pilot later reported in writing that at no time did the airplane attain liftoff speed, and that a wind gust caused a ground loop. The pilot-rated passenger who is an FAA certificated airframe and powerplant mechanic verbally reported that he was onboard the airplane to check whether the installed transponder was operational. He boarded the airplane, donned a headset to communicate with the pilot, and by habit buckled his seatbelt though there was no intent for flight. He was not paying attention to what was occurring, and reported he did not know how fast the pilot was taxiing or whether engine power was increased at any point while he was on the airplane. He was looking at a sectional for a planned future flight, and reported the pilot advised him with words to the effect that the airplane was going to crash. He looked up, saw trees, braced for impact, and the airplane mushed into trees. He exited the airplane using the left door, as the right door was blocked by obstructions and the way the airplane was resting. He further stated the airplane was traveling westbound from the pilot's hangar towards the runway, and the wind was from the west or southwest at 11-13 miles per hour (mph). He also stated that the airplane was equipped with a short takeoff and landing (STOL) kit and could become airborne at 40-45 mph. A pilot-rated witness reported that he heard engine power applied and observed the airplane flying westbound, climbing steeply to an estimated 100 feet above ground level. The airplane then banked abruptly to the left about 45 degrees angle of bank, and he then heard engine power reduced. The airplane then settled to the ground where he heard two impacts. He did not hear any discrepancy related to the engine, and reported it sounded strong and steady, with no sputtering. He reported that the pilot's house is located approximately 400-450 feet east of the north/south oriented runway. The pilot provided a statement from an individual who reported hearing an engine start, followed by running at idle speed. He then heard the engine rpm increase to what he thought would be for taxiing. He then heard the engine sound increase to a very high sound for 4-5 seconds followed by decreasing to a low rpm sound. He then heard a "thump, thump, thump" sound and drove to the runway where he observed the pilot and passenger walking from the airplane that was located in weeds west of the runway approximately 25 feet. That person reported seeing ground scars in the, "soft sandy earth leading to the aircraft." Review of the FAA Flight Training Handbook revealed that with respect to taxiing, the taxi speed should be such that when throttle is closed, the airplane can be stopped promptly.