On November 30, 2011, approximately 1115 central standard time, a Cessna 305A, N6735Q, was substantially damaged during a forced landing near Gillespie County Airport (T82), Fredericksburg, Texas. Visual meteorological conditions prevailed at the time of the accident. The local flight was conducted under the provisions of 14 Code of Federal Regulations Part 91 without a flight plan. The pilot was not injured. The flight departed New Braunfels, Texas, approximately 1030. While on approach to the runway the pilot added power to the engine to adjust his approach path and the engine did not respond. The pilot was unable to restart the engine and set up for a forced landing to a nearby field. During the forced landing, the airplane struck a wire and then the ground. The right main landing gear was bent, the firewall was wrinkled, and the fuselage adjacent to the right wing strut was buckled. Examination of the airplane revealed that caps were present on the fuel tank vent lines. When the caps were removed, pressure release and air movement could be heard from the tanks. The fuel tanks contained an adequate supply of fuel. No other mechanical anomalies, malfunctions, or failures were noted which would have contributed to the accident. The pilot reported that he had placed the caps on the fuel vent lines to keep insects out of the lines and the fuel tanks and forgot to remove them during his preflight inspection.