On July 20, 2006, at 1635 Pacific daylight time, an American Champion Aircraft 7GCBC, N53SE, ground looped while landing in an unimproved area near Greenfield, California. The airplane was registered to a private individual, and was operated by the pilot under the provisions of 14 CFR Part 91. The commercial pilot, who was the sole occupant, was not injured. The airplane was substantially damaged. The airplane was registered to a private individual and was operated by the pilot under the provisions of 14 CFR Part 91. The local flight originated from the Metz Airport (3CA7), Greenfield, at 1620. Visual meteorological conditions prevailed and a flight plan was not filed for the personal flight. According to the pilot's written statement, the owner and the pilot used the tail wheel equipped airplane primarily for observing wildlife in the local area and utilized its short takeoff and landing characteristics to land in areas not accessible to most other aircraft. After having routine maintenance performed on the airplane, the pilot took it out for what was planned to be a short test flight. After departing Metz airport, the pilot elected to climb straight out to a nearby ridgeline. Once on top of the ridge the pilot decided to make an "exploratory" touch-and-go landing to determine the roughness of the terrain. The wind was from the west at approximately 20 knots with gusts. On this first pass the pilot allowed the plane to slow to about 20 miles/hour (mph) during the ground roll before adding power and going around for another landing. According to the pilot, his original intent was to make three touch-and-goes before bringing the plane to a full stop, but because the first landing was uneventful, he became "over confident" and set up for a full stop landing on the second approach. After touchdown, during a ground roll of about 300 feet and with a speed below 5 mph, the airplane was "hit by a thermal or large gust of wind coming up from the left side of the ridge." The left wing rose at a rate that the pilot described as "alarmingly fast." He applied power, but he lacked the control authority to assist in the recovery. The right wing tip contacted the ground and the airplane rotated to the right on its right main tire and right wing tip through approximately 130 degrees. After 90 degrees of rotation the airplane nosed down exposing the underside of the airplane to the wind. The airplane was then blown over onto its topside. The pilot reported that the airplane sustained structural damage to the wings, vertical stabilizer/rudder, and the fuselage.