On March 28, 2004, at 1330 central standard time, a Cessna C-180, N2916C, piloted by an airline transport pilot, was substantially damaged when it nosed over after impacting a road embankment during a forced landing to a farm field near Aberdeen, South Dakota. The airplane was descending when it experienced a complete loss of engine power. The 14 CFR Part 91 personal flight was operating in visual meteorological conditions on a visual flight rules flight plan. The pilot and his passenger were not injured. The flight originated from the Jeffco Airport, Denver, Colorado at 1003 and was en route to the Aberdeen Regional Airport (ABR), Aberdeen South Dakota. According to the pilot's statement, when he was about 8 to 10 miles southwest of ABR, the main fuel tank gauges read 1/4 full and he intended to transfer fuel from the auxiliary fuel tanks at this time; however, the engine lost power prior to the transfer of fuel. He stated that he then executed a forced landing into a farm field. In a telephone interview, the pilot stated that he had descended to traffic pattern altitude and his power setting was about 24 inches of manifold pressure when the engine stopped producing power. He said that his cruise power setting was about 22 inches of manifold pressure and 2,350 RPM, and that he leaned the engine using a digital exhaust gas temperature gauge for reference. The pilot stated that the accident flight was his longest cross-country flight in the airplane since an engine conversion was installed. In a telephone interview, the pilot stated that the airplane had a STC'd (Supplemental Type Certificate) P. Ponk Aviation engine conversion installed as well as a STC'd Monarch Air auxiliary fuel tank system. The auxiliary fuel tank system consisted of a fuel tank installed in each wing and a fuel transfer pump to transfer fuel from the auxiliary fuel tank to the respective main fuel tank. The auxiliary tanks are operated by transferring fuel to the main tanks and then the main tanks deliver fuel to the engine. According to a P. Ponk Aviation representative, the converted engine produced 235 shaft horsepower. The company representative also stated that the engine would burn more fuel per hour than the stock engine. He said that at 22 to 23 inches of manifold pressure and 2,300 RPM power setting, the engine should burn about 13 gallons of fuel per hour if properly leaned for cruise flight. He stated that a power setting of 24 inches of manifold pressure and 2,400 RPM would yield about 16.5 gallons per hour. According to the Type Certificate Data Sheet (TCDS) for the airplane, the main fuel tanks had a total capacity of 60 gallons with 55 gallons useable. A postaccident examination of the airplane by a Federal Aviation Administration Maintenance Inspector revealed no pre-impact anomalies. During the examination, the airplane was righted and an examination of the engine performed. No anomalies were noted. Subsequent to that examination, the engine was started and run at a low throttle setting. Due to the damage to the propeller, a full throttle test was not performed. During the test, the engine started quickly and ran at low-power settings. The right and left main fuel tanks contained 1/2 gallon and 0 gallons of fuel remaining respectively. The right auxiliary tank had about 1 gallon of fuel remaining and the left auxiliary tank had about 13 gallons of fuel remaining. The recorded wind at the destination airport about 20 minutes after the accident was 280 degrees magnetic at 19 knots gusting to 24 knots. The accident site was about 5 statute miles south of the airport.