19961211041639A

On December 11, 1996, at 1745 central standard time, a Luscombe 8E airplane, N77974, was substantially damaged during a forced landing near Ardmore, Oklahoma. The airplane, owned and operated by a privated individual, was being operated under title 14 CFR part 91. The commercial pilot and his passneger were not injured. Visual meteorological conditions prevailed for the personal flight for which a flight plan wasn ot filed. The local flight originated approximately one hour prior to the accident. The pilot reported to an Oklahoma highway patrol officer that he had been performing touch and go landings at the Ardmore Downtown Executive Airport. He further reported that the engine lost power while on initial takeoff climb from the runway 17, and he elected to return to the runway. He added that the airplane touched down long and overran the end of the runway impacting a drainage ditch. The airport manager stated that "the pilot acquired the airplane a couple of weeks earlier and had been flying the airplane almost on a daily basis." He added that the airplanes 85 horsepower engine had been replaced with a 150 horsepower Lycoming engine "which drastically improved the climb performance of the airplane." The fuel system on the 1947 vintage airplane had also been modified by the addition of new fuel cells. Another witness at the airport reported observing "black smoke coming out of the exhaust stack as if the engine was running very rich." Examination of the airplane by the FAA inspector revealed that both main landing gear seperated from the airframe. The engine firewall and the bottom of the fuselage sustained strucural damage. The FAA inspector confirmed that the engine and fuel system of the airplane had been modified by an approved STC. The reason for loss of engine power could not be conclusively determined. Repeated attempts to obtain a completed "pilot/operator aircraft accident report" (NTSB form 6120.1/2) from the pilot/owner of the airplane were unsuccessful. (-23) pilot said he took off in the aircraft with a passenger aboard. After flying around the Ardmore area for about an hour, they returned to Ardmore down town airport to make practice landings and takeoffs (touch and go). After landing the first attempted takeoff was made. During climb, the engine started running rough and lost power. Since there was still some runway ah ead, the pilot elected to land the aircraft. After landing, the aircraft ran off the end of the runway, and into a ditch. The landing gear was damaged crossing the ditch, and the aircraft flipped over the nose and came to rest upside down. The pilot stated that he did not use any carburetor heat during any of the flight. He said a friend told him later that black smoke was coming from the exhaust when they flew the aircraft near their home. He said the engine had run rough on several occasions while reducing power.