CEN21LA221

While at an altitude of 8,000 ft mean sea level, the pilot noticed the engine oil pressure began to fluctuate. The pilot then requested to divert to the nearest airport, and shortly thereafter, the engine began to shake and lost total power. Unable to make the airport, the pilot executed a forced landing to a field. During the landing, the airplane’s nose wheel landing gear impacted a ditch. The nose landing gear collapsed, and the airplane came to rest upright. The airplane sustained substantial damage to the left wing and fuselage. Postaccident examination of the engine revealed that connecting rods 2 through 5 were fractured and separated from the crankshaft, and the connecting rod bearings were destroyed. Heat distress signatures were noted on the crankshaft connecting rod locations. The connecting rod bearings number 1 and 6 displayed significant scoring consistent with a lack of oil lubrication. It is likely the engine failure was the result of oil starvation to the connecting rod bearings, however, the reason for the oil starvation could not be determined based on the available evidence.

On May 14, 2021, at 1500 central daylight time, a Beech A36, N1875W, was substantially damaged when it was involved in an accident near Pinckneyville, Illinois. The pilot and passenger were not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. According to the pilot, while at an altitude of 8,000 ft mean sea level, he noticed the engine oil pressure began to fluctuate. The pilot contacted air traffic control and requested to divert to the nearest airport, which was the Pinckneyville-Du Quoin Airport, Pinckneyville, Illinois. Shortly thereafter, the engine began to shake and lost total power. Unable to make the airport, the pilot executed a forced landing to a field. During the landing, the airplane’s nose wheel landing gear impacted a ditch. The nose landing gear collapsed, and the airplane came to rest upright. The airplane sustained substantial damage to the left wing and fuselage (See Figure 1.). A significant amount of engine oil was noted on the underside of the fuselage. Visual examination of the engine revealed holes in the crankcase near the #1, #2, and #4 connecting rod locations. Figure 1. Airplane location Postaccident examination of the engine revealed that all crankcase and cylinder attachment bolts and nuts were secured and adequately torqued. Connecting rods 2 through 5 were fractured and separated from the crankshaft, and the connecting rod bearings were destroyed. Heat distress signatures were noted on the crankshaft connecting rod locations (See Figure 2.). The connecting rod bearings number 1 and 6 displayed significant scoring consistent with a lack of oil lubrication. Several metal fragments were noted in the oil pan, and about ½ quart of oil was drained from the engine. The reason for the oil starvation could not be determined based on the available evidence. Figure 2. Crankshaft damage at #2 connecting rod A review of the maintenance records revealed the factory-remanufactured Continental IO-520-BB engine was installed on July 4, 2017, at an engine total time of 0.0 hours. At the time of the accident, the engine had accumulated about 331 total hours. From the installation to the accident date, the completed engine maintenance were annual inspections and oil changes.