On September 29, 2006, at 1330 eastern daylight time, a Mooney M-18L, N397A, was substantially damaged during a forced landing near Lexington, Kentucky. The certificated private pilot was not injured. Visual meteorological conditions prevailed, and no flight plan was filed for the local personal flight, which departed the Madison Airport (I39), Richmond, Kentucky, at 1300, and was conducted under 14 CFR Part 91. According to the pilot, he performed a preflight inspection prior to takeoff, with no abnormalities noted. Approximately 30 minutes after takeoff, after the airplane reached its cruising altitude of 3,000 feet, the engine lost power. The pilot cycled the magnetos and applied carburetor heat; however, engine power was not regained. The pilot then performed a forced landing to a field, during which the airplane impacted a fence, substantially damaging the left wing and horizontal stabilizer. Examination of the airplane by a Federal Aviation Administration (FAA) inspector revealed that the fuel tanks and carburetor fuel bowl contained fuel. Examination of the magnetos revealed they did not produce spark when tested. The magnetos were disassembled and it was noted that the left magneto had a shorted condenser and the right magneto points were almost closed. The right magneto points were properly adjusted; the magneto was tested and produced spark. According to the aircraft maintenance records, the magnetos were last overhauled on December 22, 1966, and had 500 hours of operation since the overhaul. The airplane's most recent annual inspection was performed on May 16, 2006, with no anomalies noted.