On August 5, 2000, about 1845 Eastern Daylight Time, a Cessna 140, N73044, was substantially damaged after it experienced a power loss during a go-around at Post Mills Airport, Post Mills, Vermont. The certificated airline transport pilot received minor injuries. Visual meteorological conditions prevailed. No flight plan had been filed for the personal flight that was conducted under 14 CFR Part 91. The pilot reported that he was returning home from Rockland, Maine, and entered the traffic pattern at Post Mills for landing. The takeoff and en route phase of the flight had been conducted with the fuel selector on the left tank. While on base leg for Runway 04, the fuel selector was repositioned to the right tank, which was full. On final approach, when the airplane was about 150 to 200 feet above the runway, an ultralight pulled in front of the pilot and he initiated a go-around. The pilot first turned to the right, to parallel the runway on the right side, after which, the engine lost power. The pilot stated that he turned the fuel selector, magneto switch, and master switch, each to off as the airplane began brushing the tops of the trees. The airplane descended through trees and came to rest on the ground in a nose low attitude. An inspector from the Federal Aviation Administration (FAA) examined the airplane and reported the fuel selector was in the OFF position. There was no evidence of a fuel spill on the ground, and interviews with local fire department personnel, who initially responded to the accident site, revealed the odor of fuel was not detected. The left fuel tank was empty, and when the cap was loosened on the right tank, fuel gushed out around the edges of the cap. When the fuel selector was positioned to the right tank, fuel flowed from the right tank to the sump, which was broken, and the odor of fuel was detected in the air. According to the pilot, he had been airborne for 1 hour, 43 minutes. According to the Cessna 140 owner's manual, the capacity of the wing fuel tanks was 12.5 gallons each.