On March 22, 2010, at about 1100 eastern daylight time, a Cessna 150L, N6589G, was substantially damaged during a forced landing following a loss of engine power while attempting to land at Winter Haven’s Gilbert Airport (GIF), Winter Haven, Florida. The certificated flight instructor (CFI) and student pilot were not injured. Visual meteorological conditions prevailed, and no flight plan was filed for the local instructional flight conducted under the provisions of 14 Code of Federal Regulations Part 91. In written statements, and during separate telephone interviews, the pilots reported that they were turning from the base leg of the traffic pattern to the final leg, to land on runway 23. They completed the before landing checklist, before the student pilot reduced the throttle to 2,000 rpm. Shortly thereafter, the engine power dropped to 1,500 rpm without any input from the student pilot. The student pilot increased to the throttle until the engine reached 1,800 rpm. The engine maintained that power setting for about 20 seconds, before losing power completely. When the engine lost power, the airplane was about 500 feet above ground level, and during the descent neither pilot attempted to restart the engine. The CFI took control of the airplane and performed a forced landing to a field near the airport. During the landing roll, the nose wheel encountered rough terrain, and the airplane nosed over and came to rest inverted. The airplane was examined at the accident scene by a Federal Aviation Administration (FAA) inspector. According to the inspector, the airplane's firewall and empennage were substantially damaged. The airplane came to rest in an inverted, left wing low attitude. About four gallons of fuel were drained from the left wing fuel tank and gascolator. The right wing fuel tank was absent of fuel. On April 1, 2010, a detailed examination of the engine was performed by two FAA inspectors. The magnetos were tested and found to operate normally. The carburetor was disassembled and inspected, and no evidence of any leakage or contamination was noted. A compression check was performed and all cylinders displayed acceptable results. All spark plugs were removed and had indication of normal function, except for the lower spark plug on cylinder four, which was oil soaked. No evidence of any mechanical malfunction was noted by either inspector during the examination. According to FAA records, the CFI held a commercial pilot certificate with ratings for airplane single engine land, multi-engine land, and instrument airplane, and a flight instructor certificate with ratings for airplane single engine, airplane multi-engine, and instrument airplane. His most recent second class medical certificate was issued on November 20, 2009. The pilot reported approximately 2,800 hours of flight experience, of which 1,000 were in the accident airplane make and model. According to FAA records, the student pilot was issued a third class medical certificate on July 25, 2008. FAA records indicated that the airplane was manufactured in 1970, and was registered to an individual in September 2009. It was equipped with a 100-horsepower, Teledyne-Continental Motors O-200 engine. It was a two-place, all-metal, high-wing, single-engine, cantilever monoplane with fixed tricycle landing gear. Review of the engine logbooks revealed that the last engine overhaul was performed on June 1, 1995, at an engine total time of 1,687.7 hours. The last engine inspection was performed on May 16, 2009, at an engine total time of 2,329.9 hours. At the time of the accident, the engine tachometer indicated approximately 2,472 hours total time. At 1050, the weather reported at GIF included winds from 250 degrees at 6 knots; visibility 10 statute miles; scattered clouds at 15,000 feet; temperature 16 degrees Celsius (C); dew point 11 degrees C; and the altimeter setting was 30.00 inches of mercury. Review of an FAA Carburetor Icing Chart revealed "Serious icing - glide power" for a temperature of 16 degrees Celsius and a dew point of 11 degrees Celsius. The pilots reported using carburetor heat as they reduced the engine power, once they had entered the airport traffic pattern.