ERA17LA185

The private pilot reported that, about 20 minutes into a cross-country, personal flight, he noticed a loss of oil pressure, Subsequently, he attempted to divert to a nearby airport. The pilot stated that, a few minutes later, the engine began to "shudder," making it difficult to control the airplane, and the oil temperature had increased, so he decided to shut down the engine. The pilot was unable to glide the airplane to the diversionary airport, so he conducted an off-airport landing at a nearby field, during which the airplane struck a utility pole, which resulted in the left wing separating from the airplane. Examination of the airframe revealed oil streaks along the fuselage belly aft of the engine breather tube. Metal fragments were found trapped in the oil suction screen. About 1/4 quart of oil was present in the sump. Examination of the engine revealed that the crankcase and oil sump were intact, and no indications of oil leaks from the crankcase were found. Thumb compression and suction were established on all cylinders except for the No. 6 cylinder. The No. 6 connecting rod was separated from the crankshaft, and the connecting rod journal and rod end were discolored, smeared, and had gouges, consistent with thermal damage. Remnants of connecting rod bearing material were found loose inside the crankcase. A borescope examination of the remaining cylinders did not reveal any damage or unusual marks. Based on this evidence, it is likely that an engine crankcase overpressurization occurred, which resulted in the ejection of nearly all the engine oil through the breather tube; the reason for the overpressurization could not be determined. The engine likely began to shudder after the overpressurizaton as a result of the No. 6 cylinder connecting rod failing due to a lack of lubrication.

On May 21, 2017, about 1355 eastern daylight time, a privately owned and operated Cessna 182S, N378ES, was substantially damaged when it impacted a utility pole and terrain during a forced landing near West Chester, Pennsylvania. The private pilot was not injured. The flight departed Trenton Mercer Airport (TTN), Trenton, New Jersey at about 1330, and was destined for Montgomery County Airpark (GAI), Gaithersburg, Maryland. Visual meteorological conditions prevailed, and an instrument flight rules flight plan was filed for the personal flight, which was conducted under the provisions of 14 Code of Federal Regulations Part 91.According to the pilot, about 20 minutes into the flight at an altitude of about 5,000 ft mean sea level, he noticed a loss of oil pressure, and the oil pressure warning light illuminated about 1 minute later. The cylinder head temperature and oil temperature indications were normal. He declared an emergency with air traffic control and received vectors to the Brandywine Airport (OQN), West Chester, Pennsylvania. A few minutes later the engine began to "shudder" making it difficult to control the airplane. At that time, the oil temperature was "high up on the gauge" and he decided to shut down the engine. About 3 miles from OQN, he determined the airplane would likely not reach the airport, and he prepared for an off-airport landing in a nearby field. During the approach to the field he noticed powerlines obstructing his path. Unable to climb above them, he descended and attempted to fly underneath the wires; however, the left wing stuck a utility pole. The airplane impacted the ground and came to rest about 200 ft beyond the pole. Examination of the airplane by a Federal Aviation Administrator (FAA) inspector revealed that the left wing was separated from the fuselage, the elevator and rudder were damaged. Oil streaks were observed along the fuselage belly, aft of the engine breather tube. An initial examination of the engine revealed that metal fragments were trapped in the oil suction screen. About 1/4 quart of oil was found in the sump. The No. 6 piston did not move when the engine was rotated by hand. According to FAA records, the pilot held a private pilot certificate with ratings for airplane single-engine land, helicopter, and instrument airplane. His most recent FAA third-class medical certificate was issued April 6, 2016. The pilot reported 2,100 hours of total flight experience of which 1,200 were in the same make and model as the accident airplane. The pilot reported that the airplane's most recent annual inspection was completed on September 9, 2016, about 25 flight hours prior to the accident. The engine had accrued 2,250 hours since new, and about 860 hours since overhaul. The engine was subsequently examined at a recovery facility. All major components accessories remained installed and intact. The crankcase and oil sump were intact with no punctures or other damage noted. There was no oil streaking orpooling on the engine or surrounding cowling. The spark plugs were removed, the No. 4 bottom spark plug and No. 6 top and bottom plugs were oil soaked. Thumb compression and suction were obtained on all cylinders with the exception of the No. 6 cylinder. The No. 6 cylinder was removed from the engine case. The No. 6 connecting rod was separated from the crankshaft. The connecting rod end and the crankshaft journal were discolored, smeared, and contained gouges, consistent with thermal damage. Remnants of connecting rod bearing material were found loose inside the crankcase. The crankshaft end of the connecting rod was spread open, discolored, and damaged. The rod end cap was separated from the rod, deformed, discolored and damaged. Both were consistent with thermal damage. The piston top had impact marks consisting with contact from both valves. The exhaust valve hydraulic lifter was fractured circumferentially. A borescope examination of the remaining cylinders did not reveal and damage or unusual marks. The engine oil pump was removed. The safety wire on the housing bolts was intact. The housing cover was removed. The drive coupling, gears, and housing were intact with no damage noted. The shaft turned freely by hand. An unmeasured amount of metal particles was noted inside the oil sump.