Aircraft loss of control, 255 km south-west of Warburton, Western Australia, on 17 October 2007, VH-WXC, Cessna 210M

Preliminary report released 30 November 2007.

The pilot of a Cessna Aircraft Company C210, registered VH-WXC, was fatally injured when the aircraft impacted terrain, approximately 255 km SW of Warburton, WA.

The pilot had dropped off an item of general freight at Warburton and was returning to Kalgoorlie when the accident occurred.

The aircraft was being operated at night under the visual flight rules.

During the early evening of 17 October 2007, the pilot of a Cessna Aircraft Company C210M, registration VH-WXC, was fatally injured when his aircraft impacted terrain during a flight from Warburton to Kalgoorlie, Western Australia. That flight was being conducted at night under the visual flight rules and the pilot was the sole aircraft occupant.

The aircraft was seriously damaged by impact forces. There was evidence that the engine was producing significant power at that time. The aircraft was inverted when it collided with terrain, which was consistent with an in-flight loss of control. The accident was not survivable.

Examination of the aircraft wreckage found evidence that the aircraft's suction-powered gyroscopic flight instruments were in a low energy state. That was most probably because the vacuum relief valve was at a low suction setting. There was no lockwire fitted to the associated lock nut that would have ensured the security of the vacuum relief valve's adjustment spindle. The design of the valve was such that any in-service loss of friction on the lock nut could allow the spindle to move to a lower suction setting. In consequence, the aircraft's suction-powered gyroscopic flight instruments may not have been providing reliable indications to the pilot.

The pilot was appropriately qualified to conduct the flight. However, dark night conditions probably prevailed in the vicinity of the accident site which meant that the pilot would have had few external visual cues. In such conditions, the pilot was reliant on the indications from the aircraft's flight instruments to maintain control of the aircraft. The pilot would have had limited time to identify and react to any unreliable indications from the suction-powered flight instruments.