On July 15, 2006, about 1245 eastern daylight time, a Cessna T210, N5266Y, registered to and operated by an individual, impacted with terrain during a forced landing following loss of engine power near Crestview, Florida, while on a 14 Code of Federal Regulations Part 91 personal flight. Visual meteorological conditions prevailed at the time and no flight plan was filed. The commercial-rated pilot and passenger were not injured; the airplane incurred substantial damage. The flight originated from the Ruckel Airport, Niceview, Florida, earlier that day, at about 1230. The pilot stated to the responding FAA inspector that during cruise flight the engine made a loud bang with a subsequent loss of engine power. The propeller remained windmilling and there was no response to engine controls; the restart attempts were unsuccessful. The pilot declared an emergency and elected to land in an open area within a timberland. The approach for the forced landing was with normal procedures and airspeed. The main wheels touched down first and the nose wheel followed. The nose gear dug into the terrain, separating, and the airplane flipped over before coming to a stop. The pilot and passenger exited the airplane unassisted. FAA investigators and a Teledyne Continental Motors representative performed an examination of the airplane and engine at a salvage facility after the airplane was recovered. The engine rotated when the propeller was rotated, but it was determined the accessory section of the engine was not rotating. The engine was removed from the airplane and taken to Teledyne Continental Motors factory in Mobile, Alabama, for further examination. Disassembly of the engine showed the crankshaft had fractured in the aft cheek of the No. 2 main bearing. The remains of the main bearing were found in the bottom of the engine crankcase. The NTSB Materials Laboratory, Washington, D.C., performed an examination of the fractured crankshaft. Initial examination found that post-fracture rotational mechanical damage had obliterated the entire aft fracture surface. The forward fracture surface was relatively undamaged. Optical examinations found features typical of fatigue propagation, smoothly textured surfaces with curved arrest lines, on the forward facture. Ratchets marks indicated that the fatigue initiated at multiple locations on the surface of the aft radius of the main journal surface with rearward propagation through the crank cheek. The fatigue initiation was located at the approximate tangent point between the aft journal radius and the face of the forward face of the cheek. The radius appeared smooth with no abrupt features at the origin. The material laboratory also examined the surface of the No. 2 main journal, which was circumferentially roughened but not deeply gouged. Heat tinting darkened was observed in the local areas. Other main and cylinder journals showed some local damage but none to the extent of the No. 2 main. The main bearing shells for the No. 2 main were fractured and broken up into several pieces. Many were not accounted for. The other bearing shells were intact showing various levels of wear, damage and debris embedment. The bearing shells were marked as FAA-PMA part numbers SA642720M10, indicating 0.010 inch oversize bearings. Engine logbook records show that the engine last received a major overhaul on April 22, 1998, 1,354 flight hours before the accident. On August 27, 2004, 315 flight hours before the accident; all six cylinders were replaced with new cylinders. On September 5, 2005, 141 flight hours before the accident, the airplane had an annual inspection. On July 8, 2006, about three hours before the accident, the engine had maintenance done to its turbocharger.