On June 12, 1991, a Cessna 172K (registration N79542) operated by Sheppard, Willie J was involved in an aviation accident near Jacksonville, FL. Investigators recorded the probable cause as: The cracking of the oil cooler case due to fatigue, which allowed the engine's oil supply to become exhausted. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
During cruise flight, the pilot reported engine RPM drop and zero oil pressure. The engine seized during descent for a forced landing, causing the aircraft to nose over upon touchdown.
What happened
While operating during cruise flight, the pilot observed a sudden decrease in engine revolutions per minute (RPM) accompanied by an oil pressure reading of zero. In response to this mechanical failure, the pilot initiated a descent to execute a forced landing. During this phase, the engine completely seized. The aircraft touched down in an open field, where it subsequently nosed over upon impact.
The investigation
A thorough examination of the engine was conducted to determine the root cause of the failure. Inspectors discovered that the oil cooler case had developed a crack. This structural failure was attributed to fatigue rather than external damage or manufacturing defects at the time of operation.
Probable cause
The cracking of the oil cooler case due to fatigue, which allowed the engine's oil supply to become exhausted.
What happened in the 12 Jun 1991 Cessna 172K accident near Jacksonville, FL?
During cruise flight, the pilot reported engine RPM drop and zero oil pressure. The engine seized during descent for a forced landing, causing the aircraft to nose over upon touchdown.
What aircraft was involved and where did it happen?
The accident on 12 Jun 1991 involved a Cessna 172K, registration N79542, operated by Sheppard, Willie J, at Jacksonville, FL.
What was the probable cause of the accident?
The cracking of the oil cooler case due to fatigue, which allowed the engine's oil supply to become exhausted.
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