On April 19, 2008, about 1855 Pacific daylight time, a Cessna Aircraft Company (Cessna) C175A Skylark, N6868E, experienced a reported loss of engine power and collided with transmission wires following a departure from Pine Mountain Lake Airport, Groveland, California. The pilot, who was the owner, was operating the airplane under the provisions of 14 CFR Part 91. The commercial pilot, the sole occupant, sustained serious injuries; the airplane sustained substantial damage. The local personal flight was originating from Groveland. Visual meteorological conditions prevailed, and a flight plan had not been filed.
In a written statement, the pilot reported that while conducting a high-speed taxi test, the airplane encountered a gust of wind and the airplane inadvertently became airborne. The engine experienced a loss of power and the airplane struck power lines.
An inspector from the Federal Aviation Administration (FAA) interviewed friends of the pilot who were based at Groveland. A friend stated that the pilot, who was a certificated airframe and powerplant mechanic, was conducting a series of high-speed taxi tests. The airplane's groundspeed became excessive and it encountered a gust of wind. The airplane unintentionally became airborne. The airplane continued to climb and it appeared as though the pilot was attempting to return back to the airport. After the airplane made a 90-degree turn, the engine experienced a loss of power momentarily. The engine powered up again and then quit. The airplane collided with a telephone pole and descended nose-low onto the road below.
The FAA inspector and representatives from both Cessna and Teledyne Continental Motors (TCM) conducted a post accident examination. The FAA inspector discovered that the pilot had just installed a recently purchased engine. As part of the installation he had fabricated and fitted a new fuel line just prior to the accident flight.
According to the FAA inspector, the engine and airframe examination disclosed no mechanical malfunctions or failures that would have precluded normal operation except the following. He noted that during the disassembly of the fuel line connecting the gascolator to carburetor he noticed a "flapper valve" at both end fittings; he thought this was the fuel line the pilot had recently fabricated. He stated that flapper valves can occur as a result of fittings being installed without using a mandrel, where the fitting cuts the inside of the hose creating a valve that obstructs fuel flow. The inspector opined that the flapper valve created enough of an obstruction to prevent fuel flow.
The FAA inspector added that the last annual inspection noted in the airframe logbook was on October 01, 2006, at a total time of 2,733.4 hours. No records were found for the engine or installation thereof. He further stated that the airplane had not been approved for return to service, nor did it have an airworthiness certificate.
A routine aviation weather report (METAR) generated by an Automated Surface Observation System (ASOS) at Merced Municipal Airport/Macready Field, Merced, California (located 38 nautical miles southwest from the accident site), indicated that about 2 minutes prior to the accident, winds were 260 degrees at 15 knots, gusting to 25 knots.