Preliminary report released 17 May 2010
On 29 January 2010, at about 2010 Western Standard Time a single-engine Pilatus PC-12 aircraft, registered VH-NWO, was being operated on a medical evacuation flight from Derby to Kununurra, Western Australia with four persons on board. The flight was being conducted under the Instrument Flight Rules.
At a position about 30 NM (56 km) after takeoff, the pilot reported engine problems and turned the aircraft back to the departure aerodrome. The engine subsequently failed and the pilot glided the aircraft to the aerodrome and landed safely with no reported injuries. A subsequent inspection confirmed that the engine propeller reduction gearbox had seized.
The investigation found that a number of first - stage reduction gearbox carrier bolts had failed. As a result, the engine manufacturer has reviewed a number of issues relating to engine overhaul practices and has recommended withdrawal from service of an engine from one aircraft in the Australian fleet for examination.