What happened
The flight was conducted primarily for the purpose of allowing passengers to survey sailing routes and anchorages around Santa Cruz Island. During the cruise phase, the pilot observed that the engine oil pressure was gradually decreasing. In response to this indication, the pilot decided to return to the mainland.
As the aircraft proceeded toward the coast, the oil pressure continued to drop until it reached zero. Shortly after the pressure vanished, the engine seized. The pilot subsequently ditched the aircraft in the water close to an offshore oil drilling platform. A boat from the platform later rescued the pilot and all passengers without further incident.
The investigation
The investigation focused on the mechanical failure of the engine and the circumstances surrounding the ditching. Examination of the airframe and engine components revealed no evidence of pre-impact mechanical malfunction other than the loss of oil pressure. The aircraft was recovered from the water near the specified offshore structure.
Findings
Contributing factors to this incident included the engine seizure resulting from a loss of oil pressure. The pilot's decision to return to the mainland was made in a timely manner, allowing for a controlled ditching. All occupants were rescued by personnel from the nearby platform.