On March 8, 2002, at 1200 Pacific standard time, a Piper PA-18-150, N742, lost engine power on final approach to the Winnemucca Municipal Airport (WMC), Winnemucca, Nevada, and came to rest inverted in an open field. The airplane, operated by the U.S. Department of Agriculture (USDA) under the provisions of 14 CFR Part 137, was substantially damaged. The commercial pilot and passenger were not injured. Visual meteorological conditions prevailed for the local area animal control flight. A company visual flight rules flight plan had been filed. The flight departed WMC about 0630 the morning of the accident. During an interview, the pilot stated that they had been flying for about 5.5 hours. He had fueled the airplane to capacity (36 gallons) before the day's initial takeoff at 0630. Normally, the airplane is flown between 5 and 6 hours for each flight. He also stated that there had been no previous mechanical discrepancies with the airplane In the pilot's written statement to the Safety Board he stated about 1- to 2-miles from the airport he started the descent to traffic pattern altitude. During the descent the engine began to run rough and then "died." He pushed the mixture to full rich, pulled out the carburetor heat, and switched fuel tanks. He simultaneously set the airplane up for best glide, and searched for a spot to land. While he was setting up for the emergency landing, the engine started. He pulled up on the nose to attempt to regain lost altitude, and headed for the airport. The engine quit again, and he made a forced landing in an open area that contained high brush and uneven terrain. The pilot stated that he slowed the airplane down as much as possible prior to touchdown. On the landing rollout the left main landing gear contacted some brush, and the top of a dune. The left main landing gear collapsed outward. The front of the airplane contacted the ground next and the forward momentum of the airplane caused it to come up on its nose. The airplane came to rest inverted after standing on its nose for "a couple of seconds." A Federal Aviation Administration (FAA) inspector conducted a visual examination of the engine prior to an engine run, with no discrepancies noted. The propeller was replaced, fuel was added, and an engine run was conducted. Full power was obtained on the engine with no mechanical anomalies noted. After the engine run, a compression check was conducted. Compression was obtained in all cylinders in firing order, and valve train continuity was observed. The FAA inspector stated that magneto timing was within manufacturer's specifications. The FAA inspector reported that operating the engine at 75 percent power the fuel burn rate was 9.7 gallons per hour. Total fuel capacity for this airplane was 36 gallons, 18 gallons per wing. The pilot reported to the inspector that during this flight, 30 coyotes were pursued for the purpose of predator control, and that full power was used during the pursuits. The inspector stated that full power would have increased the fuel flow to the engine.