The aircraft was in normal cruise at 1500 feet above sea level when the pilot noted a mild shuddering, and almost immediately the oil pressure reading dropped to zero. Shortly afterwards, the engine began vibrating severely, and the pilot was committed to a forced landing. In the latter stages of the approach the pilot was forced to pull-up to clear powerlines, following which the aircraft descended and struck a tree and a steel mesh fence at the edge of an industrial area. Investigation revealed that the flexible oil line between the engine and oil cooler had failed due to deterioration, resulting in oil starvation and seizure of the engine. Examination of Bureau records revealed three other recent occurrences in New South Wales where the subject hoses have failed in flight. The hoses are currently required to be inspected and tested every six years. However, the manufacturer recommends that the hoses should be replaced every five years or at engine overhaul, whichever comes first. The particular hose which failed had been in service for more than six years.
