On July 28, 1998, at 1515 hours Pacific daylight time, a Cessna 182, N6493A, experienced a loss of engine power during cruise and made a forced landing in the desert near the California City, California, airport. The airplane, operated under 14 CFR Part 91, sustained substantial damage. The commercial pilot, the sole occupant, was not injured. Visual meteorological conditions existed for the positioning flight and no flight plan was filed. The flight originated from the accident airport at 1400. The pilot reported that after dropping skydivers the engine began to run roughly as he was returning to base. During the descent from 6,500 feet mean sea level (msl), he experienced a loss of engine power and he did not attempt to restart the engine. He stated that he was approximately 8 miles northeast of the airport, completed the emergency checklist, and established best glide speed. The pilot stated that there were no obstructions between his current position and the airport. He reported that the airplane was not going to make the airport, so he conducted a forced landing on the desert floor. He attempted a soft field landing; however, the desert floor was "too soft and the nose wheel [dug] into it and [collapsed]." The airplane fuel system and engine were inspected by a Federal Aviation Administration (FAA) certified repair station on behalf of the Safety Board (report appended to file). Examination of the fuel system revealed that there was fuel in the fuel line from the gascolator to the carburetor. The carburetor drain plug was removed and the fuel selector was operated in the left, right, and both settings; fuel was observed to be "flowing in each position, and this indicated proper operation of the [carburetor] float valve." The fuel selector was noted to have a "minor leak from the top of the unit." No further anomalies were noted with the fuel system. No discrepancies were noted with the engine. An FAA inspector examined the airplane and available airplane documents. A squawk sheet was found in the airplane stating that the magnetos were not grounded; the exhaust gas temperature and cylinder head temperature gages were inoperative; and that fuel needed to be in both tanks and the fuel selector should be in the both position. According to the Cessna Aircraft, there is a total of 27.5 gallons per wing with a total of 55 gallons. The unusable per wing in all flight conditions is 2.5 gallons. The unusable per wing in level flight only is 1.0 gallon per tank. The pilot stated that he had fueled the airplane with a total of approximately 3.5 inches. According to Cessna this equates to approximately 15.5 gallons. Cruise and range performance charts out of the Pilot's Operating Handbook (POH) state that at 6,500 feet msl fuel burn is approximately 13.9 gallons an hour. The pilot stated that he flew for 1 1/2 hours before the accident. He had returned to the airport, picked up skydivers, took them to the drop zone, and was returning to base when the engine began to run roughly. The previous operator was the Las Vegas Skydive Center in Jean, Nevada. The aircraft had been loaned to the California City Skydive Center. After the accident an attempt was made to examine the airframe and powerplant logbooks. Through the Las Vegas, Nevada, Flight Standards District Office it was learned that the Las Vegas Skydive Center had closed, and the logbooks were unable to be located.