Incident Overview
A ferry flight from California to Hawaii experienced a gradual loss of oil pressure, ultimately resulting in a complete loss of engine power. The aircraft was forced to ditch at sea, and the pilot was subsequently rescued by a surface vessel. The aircraft sank after the ditching.
Sequence of Events
The first indication of trouble occurred approximately 11 hours into the flight, when the oil pressure dropped by 5 psi, reading 50 psi. Thirty minutes later, the oil pressure decreased further to 45 psi. The pilot issued a mayday call, and a Navy P3 aircraft intercepted about 1.5 hours later, by which time the oil pressure had reached the red line. Despite the pressure drop, oil temperature remained normal.
About 14.5 hours into the flight, the engine began making a clacking sound and subsequently lost power. The propeller continued to windmill. The ditching was successful, and the pilot was picked up by a surface vessel. The aircraft sank.
Oil Consumption History
Prior to the incident, the aircraft's oil consumption was approximately 1 quart over 17 hours of operation. Accompanying aircraft observed no leaks or smoke during the flight.
Probable Cause
The probable cause of the incident was a gradual loss of oil pressure that led to complete engine power loss.