On August 3, 1993, about 1730 hours Pacific daylight time, a Taylorcraft BC-12-D, N95907, collided with terrain while attempting a return to runway maneuver at the Mountain Valley Airport, Tehachapi, California. The return to runway attempt was precipitated by a total loss of engine power during the takeoff initial climb. Visual meteorological conditions prevailed for the operation and a VFR flight plan was filed. The airplane was destroyed in the ground collision sequence and the commercial pilot, the sole occupant, sustained fatal injuries. The flight was originating at the time of the mishap as a personal cross country flight to Thermal, California. The pilot was working as a tow plane pilot for sailplanes. According to his log book, he performed 14 tows during the day of the accident. During the day, the pilot borrowed some fuel containers to purchase automobile fuel for the Taylorcraft. The airport manager reported during the initial accident notification that the aircraft experienced a loss of engine power during the takeoff and initial climb. The manager stated that the aircraft was attempting a return to runway maneuver when it apparently stalled in the turn and descended nose first to ground impact. An FAA airworthiness inspector from the Van Nuys Flight Standards District Office responded to the accident site and examined the aircraft. He reported that he found the fuel selector valves in the "OFF" position. The FAA inspector performed a weight and balance on the airplane and its contents at the time of the accident. According to the calculations, the airplanes weight at takeoff was 1,229 pounds with a most rearward center of gravity of 20.5 inches. According to the FAA Type Certificate Data, the maximum gross weight is 1,200 pounds with an aft center of gravity limit of 20.0 inches. Further examination, according to the inspector, revealed that the pilot was using automobile gasoline and had borrowed gasoline containers earlier in the day to purchase gasoline at a local automobile station for the airplane. The airplane did not have a Supplemental Type Certificate for the use of automobile fuel and the carburetor did not have the manufacturers recommended needle valve to be compatible with automobile gasoline.