Accident Details
On July 31, 2016, at approximately 1135 central daylight time, a Cessna 172F airplane, registration N211FC, collided with a berm during a forced landing near Newark, Illinois. The private pilot was not injured, and the airplane was substantially damaged. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight without a flight plan. Day visual meteorological conditions prevailed. The cross-country flight departed Wittman Regional Airport (OSH), Oshkosh, Wisconsin, about 0945, and was en route to Morris Municipal Airport (C09), Morris, Illinois.
Engine Performance and Forced Landing
The pilot reported that the airplane experienced a sudden loss of engine power about 1 hour 50 minutes into the flight at a cruise altitude of 2,500 ft mean sea level. The engine continued to run but exhibited excessive vibration and a significant loss of power. The pilot increased the fuel mixture to full-rich, confirmed the fuel selector was positioned to draw from both tanks, and verified the ignition switch was set to both. He did not engage the carburetor heat. Engine performance did not improve; oil temperature and pressure gauges indicated normal readings. The engine eventually began making a "squeaking" noise. The pilot performed a forced landing to an open field because the engine could not maintain altitude. During the landing roll, the nose landing gear collapsed upon impacting a berm, and the airplane came to rest in a nose-down attitude. The engine firewall and lower fuselage structure were damaged.
Engine Examination
A Federal Aviation Administration (FAA) Inspector examined the engine after recovery. The crankshaft could be rotated by hand but not a full turn. Upper spark plugs for cylinders No. 1-3 exhibited normal wear. The upper and lower spark plugs for the No. 4 cylinder showed significant impact damage. The No. 4 cylinder was removed, revealing impact damage to the piston face and piston chamber top. The No. 4 exhaust valve was not in its normal position in the cylinder head. A portion of the valve was embedded in the cylinder head; another portion and the valve stem were found in the left muffler. About half of the No. 4 exhaust valve was located, and the recovered portions exhibited significant impact damage.
Background
The airplane was powered by a 145-horsepower, 6-cylinder Continental O-300-D reciprocating engine, serial number 28231-D-3-D. The most recent annual inspection was completed on January 26, 2016. At the time of the accident, the engine had accumulated 2,146.9 hours since its last major overhaul on January 6, 1989. According to available maintenance documentation, the No. 4 cylinder exhaust valve had not been repaired or replaced since the last overhaul. The engine maintenance manual recommends a time between overhaul (TBO) of 1,800 hours or 12 years, whichever occurs first. Title 14 CFR Part 91 does not require compliance with manufacturer TBO intervals if annual inspections are met.