Flight Details
The pilot submitted a flight plan for a charter category, single pilot, Instrument Flight Rules flight from Darwin to Port Keats and return. The aircraft, a Piper Aerostar 600A, carried six passengers on the outbound leg. Departure from Darwin occurred at 2014 Central Standard Time, and the aircraft arrived at Port Keats at 2106 after an uneventful flight.
Sequence of Events
After the passengers disembarked at Port Keats, the pilot prepared to return to Darwin alone. At 2119 hours, the pilot reported taxiing for runway 34 to Brisbane Flight Service—the last radio contact with the aircraft. Witnesses observed nothing unusual during taxi and takeoff from runway 34.
When a departure report was not received, a distress phase was declared, and a search was initiated.
Wreckage Discovery
The following morning, major structural components of the aircraft, including the outer left wing, were located approximately 24 km north-east of Port Keats aerodrome, close to the flight-planned track. The main portion of wreckage was found four days later, destroyed by ground impact. The impact crater was a considerable distance from the previously located structural components, indicating that an inflight breakup had occurred. The accident was not survivable.
Probable Cause
The official investigation determined that shortly after departure from Port Keats aerodrome, the pilot lost control of the aircraft for reasons unknown. Aerodynamic loading of the left wing in excess of the ultimate load limit occurred, resulting in an inflight breakup of the airframe. The investigation was unable to determine the circumstances that led to the loss of control and subsequent inflight breakup of the aircraft.