On October 18, 1998, at 1000 central daylight time, a Mooney M20A airplane, N6534B, was substantially damaged during a forced landing following the loss of engine power near Oklahoma City, Oklahoma. The instrument rated private pilot and her two passengers were not injured. The airplane was owned and operated by the pilot under Title 14 CFR Part 91. Visual meteorological conditions prevailed for the personal flight for which a flight plan was not filed. The flight originated from the Sundance Airpark, near Yukon, Oklahoma, approximately 10 minutes prior to the accident. In the enclosed NTSB Form 6120.1/2, the pilot stated that she checked the fuel tanks prior to takeoff and noted that the left fuel tank was 3/4 full and the right fuel tank was "very low." During takeoff; however, the pilot positioned the fuel selector on the right fuel tank. The engine lost power soon after departing from runway 35, while at an altitude of 400 to 500 feet AGL. The pilot added that she thought she had selected the fullest tank and "assumed there was an engine malfunction," so she did not switch the fuel selector to the left tank. The 400 hour pilot landed the airplane in an open pasture with the landing gear extended. During the landing roll, the airplane collided with a terrace, collapsing the landing gear. In a telephonic interview, the pilot reported to the NTSB investigator-in-charge, that her total concentration after the loss of power was "to fly the airplane to a safe landing." According to local law enforcement personnel that responded to the accident site, the pilot reported that "the airplane ran out of fuel." Examination of the airplane revealed that the left main fuel cell was approximately 3/4 full. The pilot added that the 1959 vintage airplane was equipped with a single fuel gauge controlled by a two-position toggle switch which selects which fuel tank quantity is displayed. Examination of the airplane by the FAA inspector and the owner revealed that both wooden wings and the flaps sustained structural damage.