19990823042369A

(.4)During cruise flight about 49 minutes after takeoff, the pilot declared a mayday and reported that the engine quit. Unable to land at the closest airport, he maneuvered the airplane for a forced landing to a field and collided with trees while descending. The nos. 1, 2, and 4 connecting rods were broken; heat distress was noted at cylinder nos. 1, 2, and 4 connecting rod journals. Fretting was noted at the upper support boss for the no. 2 main bearing. Damage to the bearing saddle area on both crankcase halves for the no. 2 main bearing was noted. Brown discoloration was noted at the no. 2 main bearing journal. The engine was overhauled December 1985, installed April 1986, and January 1994, the nos. 3, and 6 cylinders were replaced and the top of the crankcase was sealed. The engine accumulated approximately 995 hours since overhaul and 328 hours since installation of the replacement cylinders. The thru bolt located adjacent to the fretted support boss of the no. 2 main bearing is used to secure the nos. 2, and 3 cylinders. The engine oil was changed last approximately 65 hours earlier; the engine manufacturer recommends oil change each 25 hours. (-23) a/c departed VFR from tri-cities airport enroute to nashville, TX. At cruise altitude pilot experienced engine failure. Pilot declared mayday to atl-atc. Pilot attempted emergency landing in hay field. Pilot lowered landing gear and descended into the trees. Came to rest at the edge of the intended field. Pilot received a serious back injury. Pilot did not hold a valid medical certificate. Revoked in may 1990. Engine suffered massive failure. Two holes in engine case above number 2 and 4 rods. Engine is awaiting teardown by FAA and the manufacture.