On February 19, 2003, about 1000 eastern standard time, a Cessna 172SP, N197ME, was substantially damaged during a forced landing near Flemington, New Jersey, following a total loss of engine power. The certificated private pilot was not injured. Visual meteorological conditions (VMC) prevailed for the local personal flight. No flight plan was filed, and the flight was conducted under 14 CFR Part 91. The pilot arrived at the airport about 0900 with the intention of practicing some instrument approaches in VMC. He preflighted the airplane, noted no anomalies, and then boarded. The pilot taxied the airplane short of runway 22, completed the engine runup checks, and then performed a normal takeoff. Once airborne, he executed the VOR 23 approach to Doylestown Airport (DYL) Doylestown, Pennsylvania, and at the missed approach point, advanced the throttle to execute a climbing right turn to repeat the approach. After reaching 2,000 feet msl, and while flying the inbound leg of the procedure turn, the engine lost all power. The loss of power was smooth, and took approximately 5 seconds. During the descent, the pilot attempted to restart the engine using the checklist, but the engine did not respond. Unable to reach an airport, he setup to conduct a forced landing to an open field. The airplane touched down upslope, main landing gear first, and then rolled approximately 200 feet before settling into soft ground. The nose wheel contacted the ground, collapsed, and the airplane spun 180 degrees to the left before coming to a stop. The pilot egressed unassisted, and reported the accident and his location to air traffic control via mobile phone. The engine was removed from the airframe, and a teardown was conducted on February 28, 2003, at the engine manufacture's facility under the supervision of a Federal Aviation Administration inspector. During the examination, the accessory section was opened, and the following conditions were identified. The accessory drive gear bolt was loose, the bolt locking plate was in place, and the accessory drive gear dowel was broken. Examination of the accessory gear assembly revealed, the bolt threads were not damaged, the bolt met manufacturing specifications, and the fracture surface for the accessory drive gear dowel was consistent with overload. According to the engine manufacturer, two additional engines were examined that were assembled and inspected by the same individuals as the accident engine. One was built prior to the accident engine and the other afterwards. In both cases, no discrepancies were identified. According to the manufacturer's assembly and inspection procedures, the required torque for installing the accessory drive gear bolt was 17 foot pounds, and that the locking plate would secure the bolt in place. According to maintenance records, the engine was manufactured approximately 2 years before the accident, and had accumulated approximately 656 hours of flight time. In addition, the records indicated that the accessory drive gear bolt had not been removed since being installed by the manufacturer.