FTW98LA233

The airplane collided with trees following an inadvertent engine start. The pilot stated that the tandem airplane was positioned on a taxiway with the right wheel chocked and his wife seated in the rear seat with her seatbelt fastened. The pilot attempted to start the engine by 'hand propping' several times, but was not successful. He thought that he had 'flooded' the engine and decided to clear the engine by turning the propeller again with the magento OFF, fuel valve CLOSED, and throttle FULL OPEN. The pilot thinks he mistakenly turned the magneto ON, which resulted in the engine starting when he began turning the propeller.

On May 19, 1998, approximately 1900 central daylight time, an Aeronca 7AC airplane, N3504E, owned and operated by a private individual, was substantially damaged following a loss of control while hand propping the engine at the Sheridan Municipal Airport, near Sheridan, Arkansas. The private pilot was seriously injured and the passenger was not injured. Visual meteorological conditions prevailed for the proposed Title 14 CFR Part 91 personal flight, for which a flight plan was not filed.

The pilot reported in the Pilot/Operator Aircraft Accident Report (NTSB Form 6120.1/2) that the tandem airplane was positioned on a taxiway, with his wife seated in the rear seat with her seatbelt fastened, in preparation for a local flight. The pilot stated that "[he] tried to get her to apply the heel brakes in the backseat location, but her legs are short and he [didn't think] she had applied too much pressure, as the seats are fixed and not adjustable." The pilot stated that he placed "small wooden chocks" under the right main wheel. He then turned the "fuel valve to the OPEN position, magneto switch OFF, applied two pumps of primer and turned the propeller four to five times by hand." He then turned the "magneto switch ON, positioned the throttle at 1/4 OPEN, fuel valve OPEN" and attempted to start the engine by turning the propeller. The engine did not start.

The pilot then turned the "magneto switch OFF, primed the engine again and turned the propeller several more times." He then turned the "magneto ON, cracked the throttle OPEN" and again tried to start the engine by turning the propeller by hand. The engine did not start and the pilot stated that he turned the "magneto switch OFF, turned the fuel valve to the CLOSED position, positioned the throttle at IDLE/CUTOFF" and turned the propeller several more times. The pilot thought that the engine was flooded and returned to the cockpit to verify that the "magneto switch was OFF, fuel valve CLOSED, and throttle FULL OPEN," before turning the propeller by hand to clear the engine. The pilot stated that he "thinks" he mistakenly turned the "magneto switch ON."

The pilot turned the propeller and the engine started to run at high RPM. The airplane jumped the chocks and the pilot attempted to hold onto the airplane by the wing strut; however, he lost his grip and the airplane continued approximately 100 feet before exiting the taxiway. The airplane struck "small pine saplings" with the right wing tip and then hit a tree "head-on," and came to a stop.

The FAA inspector who examined the aircraft at the site reported that the engine cowling was damaged and the propeller blades were bent. The left and right wing sustained structural damage, including the left wing strut.