Accident Summary
On August 8, 2019, at approximately 0955 eastern daylight time, a Cessna R172K airplane, registration N1609V, was substantially damaged during a forced landing near North Garden, Virginia. The pilot, who was the sole occupant, received minor injuries. The flight was conducted under Title 14 Code of Federal Regulations Part 91 as a personal flight.
According to the pilot, while cruising at 9,500 ft mean sea level, an "Oil Pressure" warning appeared on the primary flight display. The pilot diverted toward Charlottesville-Albemarle Airport (CHO), about 20 miles away. Shortly thereafter, the engine lost total power. The pilot executed a forced landing to a field. During the landing roll, the airplane struck a fence and a large round hay bale, nosed over, and came to rest inverted. Both wings, the empennage, and the fuselage sustained substantial damage. The pilot reported no visible oil leaks during the emergency.
Engine Examination
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.
Maintenance Aspects
Teledyne Continental Aircraft Engine Service Bulletin SB96-4, issued April 12, 1996, informed customers of the availability of improved oil pump gears and required replacement of the oil pump drive gear and oil suction screens at the time of the next overhaul or anytime those parts required replacement. Examination of the engine determined that this service bulletin had not been complied with. Maintenance records for the engine recovered during the investigation dated 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.