On March 30, 2008, about 1430 Pacific daylight time, a Cessna 180K, N95ME, was substantially damaged during a forced landing following a loss of engine power while in the traffic pattern at the Benton Field Airport (O85), Redding, California. The airplane was registered to Tres Amigos Flying Club, LLC, and operated by the pilot under the provisions of Title 14 Code of Federal Regulations Part 91. The commercial pilot was seriously injured. Visual meteorological conditions prevailed, and no flight plan was filed for the local flight. The personal flight originated from O85 about 5 minutes prior to the accident. The pilot reported that after departure, he intended to remain within the airport traffic pattern to practice a series of landings. As the airplane was abeam the runway numbers for runway 33, the pilot extended 10 degrees of flaps and began configuring the airplane for landing. The pilot stated that he thought the fuel selector valve was on the "left" tank and rotated the handle 1/4 turn in the clockwise direction to a position he thought was "both." The pilot initiated a turn to base leg when he realized the airplane was slightly low and attempted to increase the engine power setting. He noticed that the engine had lost power and immediately retracted the flaps while initiating a forced landing to an area southwest of runway 33. Subsequently, the airplane landed hard on a rising embankment near the runway and came to rest upright. The pilot added that the fuel selector valve was actually in the "right" position and when he rotated the fuel selector handle, he had inadvertently positioned the valve to the "off" position. The pilot stated that there were no mechanical anomalies with the engine or airframe prior to the accident. Examination of the airplane by a Federal Aviation Administration inspector revealed that the fuselage and both wings sustained substantial damage.