On August 25, 2011, at 1245 central daylight time, a Cessna model 140 airplane, N72688, was substantially damaged while landing at Monmouth Municipal Airport (C66), Monmouth, Illinois. The pilot was not injured. The airplane was registered to and operated by the private pilot under the provisions of 14 Code of Federal Regulations Part 91. Day visual meteorological conditions prevailed for the flight, which was operated without a flight plan. The local flight departed at 1200. The pilot reported that he was landing the tailwheel-equipped airplane on runway 2 when the accident occurred. The airplane's tail inadvertently became airborne during the landing roll, and he was unable to regain control before the airplane nosed over. The airplane slid for several yards before coming to rest upside down on the runway centerline facing the opposite runway heading. The fuselage, vertical stabilizer, and rudder were substantially damaged during the accident. The pilot reported that there were no preimpact mechanical malfunctions or failures that would have precluded the normal operation of the airplane. The pilot stated that he likely landed with a tailwind. He added that the accident could have been prevented had he determined the wind direction and speed from the airport's wind sock before landing. The nearest aviation weather observation station with recorded historical weather information was at Galesburg Municipal Airport (KGBG), about 10.5 miles east of the accident site, which was equipped with an automated surface observing system (ASOS). At 1235, the KGBG ASOS reported the following weather conditions: wind 330 degrees at 7 knots; visibility 10 miles; sky clear; temperature 28 degrees Celsius; dew point 11 degrees Celsius; altimeter setting 30.04 inches of mercury. A review of historical wind data indicated that the prevailing wind had been from the north-northwest between 4 and 7 knots during the previous four hours.