On September 14, 1994, a Mooney M20E (registration N6944U) was involved in an aviation accident near Plymouth, MI. Investigators recorded the probable cause as: The pilot's decision to fly with an isolated oil cooler, which resulted in a total loss of engine power due to lack of oil pressure. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
A pilot experienced a total loss of engine power after attempting to fly with an oil cooler leak capped off, leading to zero oil pressure and a forced landing attempt.
What happened
The pilot reported that the airplane developed an oil leak in the oil cooler prior to departure. To address the issue, he isolated the leak by capping the oil lines connecting the engine to the cooler and then initiated flight. Approximately ten minutes into the flight, the oil pressure dropped to zero. The pilot attempted a forced landing while the engine began running rough, shortly thereafter suffering a total loss of power.
The investigation
The investigation focused on the mechanical state of the aircraft following the incident. The primary finding was the isolation of the oil cooler via capped lines, which prevented proper lubrication circulation during operation.
Probable cause
The pilot's decision to fly with an isolated oil cooler, which resulted in a total loss of engine power due to lack of oil pressure.