What happened
On a charter flight traveling from Broome to Koolan Island, Western Australia, the pilot observed a simultaneous decrease in engine torque and oil pressure while cruising at approximately 9,500 feet. Despite attempts to compensate by increasing the power lever, the decline in torque and oil pressure persisted. Following the illumination of a low oil pressure warning light, the pilot elected to shut down the engine and divert to the nearby Beagle Bay airstrip.
During the final approach to the runway, the pilot noted that the aircraft was maintaining excessive airspeed and an altitude that was too high. The aircraft landed approximately halfway down the runway and subsequently overran the threshold by roughly 200 metres. The sequence ended when the aircraft struck a dirt mound, causing the plane to come to rest in an inverted position. The pilot, who was the sole occupant, suffered minor injuries.
Findings
Post-accident inspections of the wreckage and site photography showed that the nose gear, left main gear, and the engine had all detached from the airframe during the accident. A significant quantity of oil was found on the underside of the aircraft, suggesting a leak occurred within the engine during the flight. Following the incident, the engine was transported to an overhaul facility for a detailed disassembly and examination under the supervision of the ATSB.