N7736K

On July 20 2004, at 1600 mountain daylight time, a Cessna P210N, N7736K, operated by a commercial pilot, was substantially damaged during a forced landing at Converse County Airport (DGW), Douglas, Wyoming. Visual meteorological conditions prevailed at the time of the accident. The personal cross-country flight was being conducted under the provisions of Title 14 CFR Part 91 on an instrument flight rules (IFR) flight plan. The pilot and three passengers were not injured. The flight to Provo, Utah, originated at Rapid City, South Dakota, approximately 1400.

According to the pilot, while in cruise flight at 22,000 feet msl, the engine "quit." The pilot stated that the propeller continued to "windmill," and at that time he noted approximately 50 gallons of fuel remaining. The pilot's attempts to restart the engine were unsuccessful. He declared an emergency and was diverted to Douglas. He broke out of the clouds at approximately 14,000 feet agl. On final approach to runway 28, the airplane's left main landing gear struck a fence post and the airplane impacted terrain approximately 200 feet short of the runway threshold. The airplane drifted to the left of the runway centerline and came to a stop in the grass. The impact collapsed the airplane's left main landing gear assembly, and buckled the left wing tip and left horizontal stabilizer.

On February 14, 2005, the engine was examined at Teledyne Continental Motors, Inc., in Mobile, Alabama. The examination revealed a 7/8-inch by 3/8-inch hole in the top of the crankcase, just forward of the number 1 cylinder. Further examination revealed that the number 2, 3, 4, 5, and 6 piston rods were fractured. The engine crankshaft was fractured at the number 2 rod journal. The crankshaft exhibited thermal discoloration and impact marks at the number 2, 3, 4, and 5 rod journals. Rotational scoring and thermal discoloration was observed on each main bearing. The crankshaft's number 2 main bearing was fragmented. Fretting was observed on the crankcase halves at the number 2 bearing through bolts. Fretting was also observed on the number 3 and 4 bearing through bolts.

According to the airplane's engine maintenance records, on May 31, 2000, at an airframe total time of 2,380.0 hours, a top overhaul was completed on all 6 cylinders. On November 17, 2003, at 2,845.0 hours, during the airplane's most recent 100-hour inspection, the engine's number 2 cylinder was replaced. At the time of the accident, the total airframe time was 3,083.0 hours.