The 2,800-hour private pilot of the single-engine airplane experienced a partial loss of engine power on takeoff. A witness, who is also an airframe and powerplant (A&P) mechanic with inspection authorization (IA), stated that he heard the engine sputtering until the airplane was approximately 250 feet above the ground (AGL); then the engine stopped running. The A&P added that the pilot almost completed a 180-degree turn in an attempt to return to the airport; however, the airplane impacted the ground about 60 feet short of the airport. The A&P moved the airplane into a hangar, and reported to the FAA that the engine broke away from the airframe and the left wing was partially separated from the fuselage. The A&P also reported to the FAA that the fuel in the left fuel tank measured 0.75 of an inch, and the fuel in the right tank measured 0.25 of an inch. On the pilot's most recent FAA medical certificate dated April 11, 1989, the pilot reported his total flight time as 2,800 hours; however, he failed to complete a Pilot/Operator Aircraft Accident Report (NTSB Form 6120.1) sent to him by the NTSB investigator-in-charge.