On June 18, 2010, about 1230 central daylight time, a Schleicher ASH 26E motorized glider, N26EL, was substantially damaged during a forced landing near Shelbyville, Tennessee. The certificated commercial pilot sustained minor injuries. Visual meteorological conditions prevailed, and no flight plan was filed for the local personal flight, which originated from Tullahoma Regional Airport (THA), Tullahoma, Tennessee. The flight was conducted under the provisions of Title 14 Code of Federal Regulations Part 91. In a telephone interview, the pilot stated that he departed in the self-launching glider for the local flight. He stated that it was a smooth day with no lift, and he had to use the engine "several times" in order to stay aloft. While returning to THA at approximately 1,000 feet, the pilot raised the engine and attempted to start it. He received a battery warning indication in the cockpit, and was unable to start the engine with the electrical system. The pilot selected a field for landing, but continued to attempt to "troubleshoot" the engine. The pilot successfully air-started the engine, and abandoned the landing approach to the field in order to continue to THA. The engine then ran for "10 to 20 seconds" before quitting, and the pilot executed a forced landing to a field. He stated that he was "not properly set up," and landed hard, which resulted in substantial damage to the glider's fuselage. The pilot stated that during post-accident inspection, he did not discover any anomalies of the fuel valves. He stated that the glider's fuel tank, which had a capacity of 4 gallons, contained about 2.5 gallons of fuel. According to Federal Aviation Administration (FAA), records, the glider was manufactured in 2006, and was registered to the pilot in December, 2009. The most recent annual inspection was completed in February, 2010. The pilot held a commercial pilot certificate with ratings for airplane single-engine land and instrument airplane; and a private pilot certificate with a glider rating. His most recent FAA third-class medical certificate was issued on February 8, 2010. The pilot reported 1,050 hours total hours of flight experience, approximately 50 hours of which were in the accident glider. At 1256, the recorded weather at Smyrna Airport (MQY), Smyrna, Tennessee, located about 30 miles south of the accident location, included variable winds at 5 knots, 10 miles visibility, few clouds at 3,700 feet, scattered clouds at 4,700 feet and 7,500 feet. The temperature was 34 degrees Celsius (C), the dew point was 22 degrees C, and the altimeter setting was 30.08 inches of mercury. The glider was examined by two FAA inspectors on July 7 and 8, 2010. The examination revealed that the engine start system and propeller pylon extension system could not be activated due to a dead battery. A charge was applied, and subsequent attempts were unsuccessful. The battery was then left to charge overnight. On the second day, examination behind the instrument panel revealed a loose cannon plug. The plug was retained in place by two clips, one of which was disconnected. Once the cannon plug was retightened, all systems routed through the panel (fuel pump, propeller pylon extension, engine start) energized immediately and functioned as designed. The engine was rotated with the electric starter, but the fuel valve was kept in the "off" position to prevent engine start. According to the inspectors, the cannon plug was very difficult to access, and that the manner in which the plug came loose could not be determined.