On July 27, 1984, a Cessna 310Q (registration CGONG) was involved in an aviation accident near Havre, MT. Investigators recorded the probable cause as: The pilot's inability to maintain altitude after shutting down the left engine due to an 'O' ring failure causing an oil leak. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
A pilot performed a forced landing in an open field after detecting decreasing oil pressure and a visible leak on the left engine during cruise flight with seven passengers aboard.
What happened
The aircraft was operating in cruise flight carrying five adults and two infants when the pilot observed a decrease in left engine oil pressure accompanied by a visible oil leak. The crew initiated an emergency shutdown of the affected engine and feathered the propeller to reduce drag. Despite these corrective actions, the aircraft was unable to maintain altitude with the remaining power. The pilot executed a forced landing in an open field without further incident.
The investigation
Post-acc examination of the left engine revealed that an 'O' ring failure was the mechanical cause of the oil leak. This component failure led directly to the loss of oil pressure and the subsequent need for engine shutdown.
Probable cause
The pilot's inability to maintain altitude after shutting down the left engine due to an 'O' ring failure causing an oil leak.