ERA09LA271

During cruise flight the pilot stated that the engine suddenly and without warning began running rough with "...much vibration." He reduced power, which reduced the vibration, and the airplane began losing altitude. He proceeded to the nearest airport but after recognizing that he would be unable to land there, he maneuvered the airplane for a forced landing in a field. Examination of the engine revealed the No. 1 cylinder exhaust valve was broken and the top of the No. 1 cylinder and piston were damaged by the broken valve. Although the engine was last overhauled on August 12, 1989, the cylinders were not replaced at that time. The overhaul entry indicates that the cylinders were only inspected and honed. Further, there was no record that the No. 1 cylinder had been removed and replaced since the engine was overhauled. The engine had accumulated approximately 1,310 hours since overhaul at the time of the accident. The reason for the No. 1 exhaust valve failure was not determined.

On April 24, 2009, about 0950 eastern daylight time, a Cessna 177, N2803X, registered to and operated by a private individual, experienced a partial loss of engine power and was substantially damaged during a forced landing in Kinston, North Carolina. Visual meteorological conditions prevailed at the time and no flight plan was filed for the 14 Code of Federal Regulations (CFR) Part 91 personal flight, from Chesapeake Regional Airport (CPK), Norfolk, Virginia, to Henderson Field Airport (ACZ), Wallace, North Carolina. The certificated private pilot and one passenger were not injured. The flight originated from CPK about 0820. The pilot stated that while flying at 2,900 feet with the power set to 2,350 rpm, en route to the destination airport, the engine suddenly and without warning began running rough with "...much vibration." He reduced power which reduced the vibration somewhat and the airplane began losing altitude. Using the on-board global positioning system (GPS) receiver he proceeded towards the nearest airport. He then noticed the exhaust gas temperature was decreasing. He reduced power to maintain best glide airspeed (70 knots), and then increased power but the response was sluggish. He again reduced power, and after recognizing that he would be unable to land at the nearest airport, he looked for a place to land. After spotting a large field ahead he maneuvered the airplane for a traffic pattern entry for the forced landing. After touchdown in the plowed field the airplane came to rest upright. Examination of the engine revealed the No. 1 cylinder exhaust valve was broken and the top of the No. 1 cylinder and piston were impact damaged by the broken valve. Review of the maintenance records revealed that although the engine was last overhauled on August 12, 1989, the cylinders were not replaced at that time. The overhaul entry indicates the cylinders were only inspected and honed. Further, there was no record that the No. 1 cylinder had been removed and replaced since the engine was overhauled. The engine had accumulated approximately 1,310 hours since overhaul at the time of the accident.