HISTORY OF FLIGHT
On March 24, 2012, about 1530 Pacific daylight time, a Jacobs RV-6A, N238RV, experienced a loss of engine power near Bow, Washington. The owner was operating the airplane under the provisions of 14 Code of Federal Regulations (CFR) Part 91. The private pilot, the sole occupant, was not injured; the airplane was substantially damaged. The local personal flight departed from Skagit Regional Airport, Burlington, Washington, about 1510, with a planned destination of Bellingham International Airport, Bellingham, Washington. Visual meteorological conditions prevailed and no flight plan had been filed.
In a telephone conversation with a National Transportation Safety Board investigator, the pilot reported that he performed two touch-and-go practice takeoffs and landings at Skagit and then departed en route to Bellingham. As the airplane climbed through 2,300 feet mean sea level (msl) to the pilot's planned altitude of 3,000 feet, he heard a loud "clunk." The engine experienced a total loss of power and the airplane began to descend. The pilot maneuvered the airplane to a field in an effort to perform an off-airport, emergency landing. While landing, the airplane's landing gear collided with a barbed wire fence and nosed over.
The pilot further stated that just prior to the accident he noted that the right fuel tank was empty and the left tank was about ¾ full. He believed that the fuel selector was positioned on the left tank. He did not attempt to restart the engine following the loss of power due to the airplane's low altitude.
TESTS AND RESEARCH
Maintenance personnel reported that prior to transporting the wreckage to the storage facility they had removed approximately 22 gallons of fuel from the left fuel tank and less than a cup from the right fuel tank. During the wreckage examination both fuel tanks were empty and there was no evidence of a fuel system breach or staining that would indicate fuel leakage.
The fuel selector was found in the forward “off” position. Air was blown from the fuel selector inlet tubes and flow continuity was established to the wing root fuel lines that connect to the right and left fuel tanks. A small amount of fuel exited the line at both wing roots. Air was also blown from the fuel selector to the carburetor and continuity was confirmed. The gascolator bowl was removed from its attachment point; it was full of a blue liquid consistent with 100LL fuel. The gascolator screen was clear of debris.
The airplane was equipped with a Lycoming O-360 engine. The engine remained attached to the engine mount assembly and firewall with minimal damage noted. Examination of the engine revealed that the engine case and all four cylinders were intact. The accessory gear case and associated accessories were present and there was no evidence of oil leakage. The engine oil sump was intact and contained about 6.25 quarts of oil. The spark plug ignition leads and the top four spark plugs were removed from the engine. The leads were intact and undamaged. The spark plug electrodes were dry and grey in color. As compared to the Champion Check-A-Plug comparison card, the top spark plugs displayed normal operating wear signatures. The engine crankshaft was manually rotated via rotation of the propeller and all four cylinders developed thumb compression. The ignition leads for the top four spark plugs sparked normally when the crankshaft was manually rotated.
During the post accident examination, no evidence of mechanical malfunction or failure with the airplane was found. A complete examination report is contained in the public docket for this accident.