Accident Details
Probable Cause and Findings
A total loss of engine power due to the failure of the oil pump drive gear.
Aircraft Information
Registered Owner (Historical)
Analysis
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.
Data Source
Data provided by the National Transportation Safety Board (NTSB). For more information on this event, visit the NTSB Records Search website. NTSB# CEN19LA258