CEN14LA031

The pilot reported that, while in cruise flight, the engine began to surge with intermittent power and that the airplane's speed and the engine's manifold pressure and oil pressure decreased. While the pilot was diverting the airplane to the nearest airport, the engine stopped producing power. The pilot established a glide toward the airport, but, when he realized that the airplane would not be able to reach the airport, he chose to perform a forced landing to a field. During the forced landing, the airplane struck a transmission wire and subsequently collided with terrain. A postaccident examination of the engine revealed that the No. 4 connecting rod had separated from its rod journal and that the rod cap bearing had partially melted into the rod journal. The No. 4 connecting rod cap and cap bolts exhibited signatures consistent with a lack of oil lubrication. No other anomalies were discovered with the engine that would have precluded normal operation. The examinations did not reveal any abnormalities that would have prevented adequate oil lubrication of the No. 4 connecting cap and cap bolts. The reason for the lack of lubrication could not be determined.

On October 25, 2013, about 1130 central daylight time, a Cessna T210L airplane, N398MA, struck a transmission wire and collided with terrain during a forced landing near Borger, Texas. The airplane was substantially damaged. The private pilot and passenger sustained minor injuries. The airplane was owned and operated by a private individual under the provisions of 14 Code of Federal Regulations Part 91 as a personal flight. Visual meteorological conditions prevailed for the flight, which operated on an instrument flight rules flight plan. The flight originated from the Thomas P Stafford Airport (KOJA), Weatherford, Oklahoma, about 1040 and was en route to Santa Fe, New Mexico. According to a statement provided by the pilot, the flight was uneventful until about one hour after takeoff, when the engine began to surge with intermittent power. The airplane's speed decreased along with the engine's manifold pressure, and oil pressure. While diverting to the Hutchinson Country Airport (BGD), Borger, Texas, the engine stopped producing power and the pilot began gliding the airplane toward the airport. When he determined that the airplane was unable to reach the airport, the pilot selected a field for a forced landing. During the forced landing, the airplane struck a transmission wire and collided with terrain. Substantial damage was sustained to both wings, the fuselage, empennage, left horizontal stabilizer and elevator. A postaccident examination of the engine was conducted by the NTSB and a technical representative from Continental Motors. The examination found the number four connecting rod separated from its rod journal, and the rod cap melted into the rod journal. The number five rod journal was thermally discolored. No other anomalies were discovered with the engine. The number four rod cap and cap bolts were examined at Continental Motors' Analytical Department, Mobile, Alabama, under the auspices of the NTSB. All components displayed signatures consistent with the lack of oil lubrication. The examinations did not reveal any abnormalities which would have prevented adequate oil lubrication to the engine components.