Accident Overview
On December 31, 2011, at approximately 1220 eastern standard time, a Piper PA-32-260 (registration N997TB) experienced a loss of engine power during cruise flight, leading to a forced landing in a farmer's field near Elk Rapids, Michigan. The commercial pilot and three passengers were not injured, while one passenger sustained minor injuries. The airplane, registered to Bulldog Air LLC, was being operated by the pilot as a personal flight under 14 CFR Part 91. Visual meteorological conditions prevailed, and no flight plan was filed. The flight had departed Cherry Capital Airport (TVC) in Traverse City, Michigan, at 1150.
Pilot Actions
The pilot reported that the engine began running rough and vibrating. He adjusted and checked the fuel mixture, throttle, magnetos, boost pump, and carburetor heat, but the vibration worsened. He decided to execute a forced landing, touching down aligned with the field's furrows. Braking proved ineffective due to the frozen ground, and the airplane impacted a line of trees at the end of the field.
Engine Examination
A Federal Aviation Administration airworthiness inspector examined the engine, a Lycoming O-540-E4B5. When the propeller was rotated by hand, cylinders number one and four exhibited little to no compression. Both cylinders were removed. The number one cylinder's exhaust valve was broken, with approximately 50 percent of the valve face missing; the piston and cylinder head showed impact marks. The number four cylinder's intact valve and seat were scarred, consistent with compression loss, and its upper and lower spark plug electrodes were forced closed. Impact marks were also present on its piston and cylinder head.
Maintenance History
Review of the engine logbooks indicated the engine was overhauled in 1994 by an airframe and powerplant (A&P) mechanic. Since that overhaul, 1,972.3 hours had been logged. No entries showed that cylinders one or four had been repaired or replaced after the overhaul. The most recent annual inspection was completed in April 2011. Lycoming Service Instruction No. 1009AT recommended overhaul every 2,000 hours or 12 years, whichever occurred first.