CEN19LA258

The pilot was on a cross country flight when an oil pressure warning displayed on the airplane’s flight display. The pilot diverted toward another airport but the engine seized enroute. The pilot performed a forced landing to a field, where the airplane hit obstacles and flipped over. Both wings, the empennage, and the fuselage sustained substantial damage. After the accident the engine was examined and determined to have failed due to an oil starvation event. The oil pump drive gear was found failed and had separated from the shaft portion of the gear assembly. The fracture surfaces were examined, and multiple fracture origins were identified. Improvements to the oil pump drive gear were made and a service bulletin was released in 1996 which required the replacement of the drive gear at the next engine overhaul. The engine examination determined that this service bulletin had not been complied with. The maintenance records that were provided only went back two years and covered two annual inspections of the engine. The most recent annual inspection record indicated that the engine had been overhauled and had accumulated 1,975 hours since overhaul. The record of the overhaul was not in the maintenance records received by investigators.

On August 8, 2019, at 0955 eastern daylight time, a Cessna R172K airplane, N1609V, was substantially damaged when it was involved in an accident near North Garden, Virginia. The pilot received minor injuries. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. The pilot reported that he was flying at 9,500 ft mean sea level (msl) when an "Oil Pressure" warning displayed on the primary flight display (PFD). The pilot diverted toward Charlottesville-Albemarle Airport (CHO), Charlottesville, Virginia, about 20 miles away. Shortly thereafter, the engine lost total power and the pilot performed a forced landing to a field. During the landing, the airplane impacted a fence and a large round hay bale, and the airplane nosed over and came to rest inverted. Both wings, the empennage, and the fuselage sustained substantial damage. The pilot did not observe any oil leaks during the emergency. A postaccident examination of the engine revealed damage consistent with an oil starvation event. The oil pump drive gear had separated and was found loose inside the accessory case. The engine crankcase accessory cover, oil pump drive gear and shaft, and the oil pump cover were sent to the National Transportation Safety Board Materials Laboratory for examination. The oil pump drive gear had separated from the shaft portion of the gear assembly near the transition radius where the driven gear and the drive gear meet. The fracture initiation point was identified on the outside diameter of the shaft and features near the shaft outside diameter were consistent with multiple fracture origins. Teledyne Continental Aircraft Engine Service Bulletin SB96-4 was issued April 12, 1996, to inform customers of the availability of improved oil pump gears and require the replacement of the oil pump drive gear and oil suction screens at the time of the next overhaul or anytime the subject parts require replacement. The examination of the engine determined that this service bulletin had not been complied with. Maintenance records for the engine were recovered during the investigation dating back to December 2017 and included annotations for the last two annual inspections. The most recent annual inspection was completed August 23, 2018, and indicated a time since overhaul of 1,975.6 hours. Whether the most recent overhaul occurred before or after the issuance of SB96-4 could not be determined.