19980519010259A

(.4)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. (-23) on may 19, 1998, at approximately 1800 hrs local time, the pilot, while attempted to hand prop his aircraft, apparently flooded the fuel system. The pilot attempted to clear the flooded situation by placing the throttle to the full on position and the mag switch to the off position. The pilot apparently failed to completely place the mag switch in the off position. While attempting to rotated the engine by hand to clear the flooded environment, the engine started, the aircraft achieved full power, jumped the chalk s placed under the main landing gear and proceeded down the taxiway. The pilot was able to physically retrieve the right-hand wing strut, apply enough rear pressure to cause the aircraft to leave the taxiway and impact vegetation adjacent to the taxiway stopping the aircraft. The pilot's wife, who was located in the rear seat, was not injured. VFR conditions existed.