An Aero Commander 690 was flying as a regular public transport flight from Williamtown to Lord Howe Island, but failed to arrive. An extensive air and sea search failed to locate the aircraft or its nine occupants (eight passengers and the pilot). Only a small number of pieces of the aircraft were found floating on the sea surface.
Report: https://www.atsb.gov.au/media/24362/aair199402804_001.pdf