On December 6, 1997, approximately 1120 mountain standard time, an Arctic S-1B2, N71AT, owned and operated by Sky Aviation Corp., was substantially damaged during a forced landing near Ten Sleep, Wyoming. The pilot and a passenger were not injured. Visual meteorological conditions prevailed, and no flight plan was filed for the aerial observation flight conducted under Title 14 CFR Part 91. The flight originated near Ten Sleep at 0930. According to the pilot's accident report, he had landed on a dirt road, picked up his passenger, and took off again to look for stray livestock. Spotting three head of cattle, the pilot reduced power and initiated a shallow descending turn. When the pilot reapplied power, the engine did not respond. After several attempts to restore engine power, the pilot was forced to land in a dry creek bed. The landing gear was sheared off during the forced landing. An FAA inspector said his examination of the airplane revealed no contaminants in the fuel, and no obstructions in the fuel vent. Fuel, air, and ignition system continuity was established.