LAX03LA209

Upon the pilot taking off in an unfamiliar airplane, the engine stuttered. The pilot aborted the takeoff. According to the owner of the airplane who witnessed the accident, it sounded as though the throttle had been "chopped." The airplane suddenly pitched up, climbed 30 feet, and then dropped 30 feet, breaking off the nose landing gear assembly. After the first impact, the engine regained power. The plane flew erratically for 1/2 the runway length approximately 30 feet above the runway. No stutter was heard after the airplane became airborne again. Instead, it sounded as though the engine was being throttled up and down. The airplane looked to be out of control and struck the ground, coming to rest in a ditch. Post accident inspection revealed the two spark plugs from the rear cylinders were "dark and sooty." Flight control continuity was established.

On June 23, 2003, about 0710 mountain standard time, an experimental Davis LG2H, N128RD, made a hard landing during an aborted takeoff near Salome, Arizona. The aborted landing was precipitated by a partial power loss. The owner was operating the airplane under the provisions of 14 CFR Part 91. The private pilot, the sole occupant, sustained serious injuries; the airplane sustained substantial damage. The local personal flight departed Western Sky Airpark (0AZ2), Salome, about 0710. Day visual meteorological conditions prevailed, and no flight plan had been filed. The primary wreckage was at 33 degrees 46 minutes north latitude and 113 degrees 38 minutes west longitude.

The airplane owner witnessed the accident. The pilot, a friend of the owner, had logged approximately 2 hours of flight time in the airplane, and was practicing touch-and-go landings for the purpose of becoming more comfortable with the airplane. Prior to the accident, he had expressed discomfort with the airplane's handling characteristics immediately before touchdown.

The owner reported that shortly before the accident, the pilot had taxied the length of the runway twice at high power and high speed. Three touch-and-go landings were performed successfully; however, the pilot expressed concern about what he believed to be an unusual oil pressure reading. After establishing that the airplane was operating normally, a takeoff was commenced and aborted after an engine stutter. A visual inspection of the automotive fuel was performed and did not reveal any contaminants. During another high power run-up, the engine ran smoothly.

The owner described several engine and control anomalies that he had experienced. He had logged about 80 hours in the airplane. Like most 'pusher' airplanes, there is no dramatic break at the occurrence of a stall. In addition, power is relatively useless when trying to initiate a stall recovery. Instead, the nose must be pushed down dramatically in order to regain airspeed. It would be quite possible to stall the airplane, descend at over 500 feet per minute, without the nose of the airplane ever pitching down.

The engine anomaly was described as a high rpm and high power skip, or stutter. This skip had never been accompanied by a power loss. After converting the Honda engine from a fuel injection to carburetor fed system and rebuilding the intake manifold 8 flight hours prior to the accident, the owner had not experienced such a problem again. There was no mixture control for this carburetor system.

Upon taking off once again, the engine sputtered and it sounded as though the throttle had been "chopped." The airplane suddenly pitched up, climbed 30 feet, and then dropped 30 feet, breaking off the nose landing gear assembly. After the first impact, the engine regained power. The plane flew erratically for 1/2 the runway length approximately 30 feet above the runway. No stutter was heard after the airplane became airborne again. Instead, it sounded as though the engine was being throttled up and down. The airplane struck the ground, coming to rest in a ditch.

The owner did not believe that the engine lost power during the sequence of events and has no doubts about the pilot's ability to fly and control the airplane safely. He attributes the accident to a sudden wind gust of which there were no visual clues, as well as the pilot's shock of making a hard landing. Both the pilot and the owner describe the wind as being from southeast about 4 knots.

Post accident inspection by a Federal Aviation Administration (FAA) inspector from the Scottsdale, Arizona, Flight Standards District Office revealed no conclusive evidence that would support the occurrence of an engine failure. The two spark plugs from the rear cylinders were described as "dark and sooty." The nose gear was found several hundred feet from the main wreckage site, and it appeared as though it had fractured one of the wooden propeller blades. The tubular frame of the airplane was relatively undamaged, and control functionality and continuity were established.