WPR11LA369

The pilot reported that he had washed the airplane the day prior to the accident. On the day of the accident he determined during the preflight inspection that the fuel and induction systems were not contaminated with water. The engine run-up was uneventful; however, when the airplane was about halfway down the runway during takeoff, the engine began to sputter. The pilot verified the positions of the fuel selector handle and carburetor heat control and pumped the throttle, which sustained engine power momentarily. The airplane could not sustain flight and the pilot subsequently force-landed it in nearby trees. During the postaccident engine inspection, no operational anomalies were noted. The pilot further reported that on previous occasions after washing the airplane the engine experienced similar instances of momentary power loss. It is likely that, although the pilot conducted an extensive preflight inspection, undetected water contamination in the fuel system resulted in a reduction of power during takeoff.

On August 4, 2011, at 0830 Pacific daylight time, a Cessna 140, N2199N, collided with trees during a forced landing near Wilkeson, Washington. The airplane sustained substantial damage. The private pilot and one passenger were not injured. The pilot, who was also the registered owner of the airplane, was operating it under the provisions of Title 14 Code of Federal Regulations Part 91. Visual meteorological conditions prevailed and no flight plan was filed for the local area flight. The pilot reported in a written statement that he had washed the airplane the day before the accident. Prior to the accident flight, he did an extensive preflight and verified no water was in the fuel. He also verified that the scat tubing was free of moisture. The run up was uneventful and during takeoff, he brought the throttle to takeoff power and released the brakes. The pilot stated that about halfway down the runway, the engine began to lose power and sputter. He verified the fuel selector and carburetor heat positions and then began pumping the throttle. He was unable to sustain engine power and force-landed the airplane into trees. The pilot reported during a phone conversation following the accident, that when he had washed the airplane on prior occasions, the airplane had experienced momentary power interruptions which he had attributed to residual water. During the post accident inspection, a Federal Aviation Administration accident coordinator test ran the engine using the airframe fuel system, fuel, and controls. The engine was test run from idle to 2,200 revolutions per minute with no operational anomalies.