On April 16, 2009, about 1015 eastern daylight time, a Cessna 152, N64988, operated by Sunrise Aviation, was substantially damaged during a forced landing to a field, following a partial loss of engine power during climbout from Cross City Airport (CTY), Cross City, Florida. The certificated private pilot and student pilot passenger received minor injuries. Visual meteorological conditions prevailed for the planned flight to Ormond Beach Municipal Airport (OMN), Ormond Beach, Florida. No flight plan was filed for the personal flight conducted under the provisions of 14 Code of Federal Regulations Part 91. The pilot reported that he departed CTY with 14 gallons of fuel. While climbing through 3,400 feet mean sea level (msl), the engine power decreased by about 300 rpm; however, the engine was running smoothly and the pilot did not hear any abnormal engine noise. The pilot then verified that the master switch was "ON," the ignition was selected to "BOTH," the fuel selector was positioned to "ON," the mixture was rich, and the throttle was in the full power position. He then positioned the carburetor heat to "ON," where it remained for the remainder of the flight. The engine power continued a steady decay to 1,400 rpm as the airplane descended to 1,000 feet msl, and the pilot performed a forced landing to a field that he had been circling. According to a Federal Aviation Administration (FAA) inspector, the recently certificated private pilot and student pilot passenger were completing a round trip cross-country flight. The airplane was "topped off" with fuel prior to the first leg of the trip. As the pilot attempted a forced landing to a field, he overshot his intended landing point. The airplane struck two fence posts and came to rest inverted in the field. During the impact, the airplane sustained structural damage to both wings and the fuselage. Examination of the wreckage by the FAA inspector revealed that due to impact damage, the crankshaft was bent. Additionally, the carburetor had separated and was impact damaged. The cabin heat was noted in the "ON" position and the carburetor heat was "OFF;" however, the carburetor box had been pulled from the airframe during impact. The inspector could not identify the reason for the engine power loss. The report weather at CTY, at 0953, was: wind from 050 degrees at 7 knots; visibility 10 miles; sky clear; temperature 17 degrees Celsius; dew point 11 degrees Celsius; altimeter 30.11 inches of mercury. Review of an FAA Carburetor Icing Chart revealed "Serious icing - glide power" for a temperature of 17 degrees Celsius and a dew point of 11 degrees Celsius.