Fairchild SA227-DC, VH-WAJ

Shortly after landing at Perth and taxiing clear of the runway, the crew of the Metroliner observed smoke accumulating and increasing in intensity in the cockpit. The crew stopped the aircraft on the taxiway, shutdown the engines, notified air traffic services of the problem and commenced disembarkation of the aircraft. After the passengers had safely disembarked, the pilot in command re-entered the aircraft and observed that, with the engines stopped, the smoke had begun to dissipate from the cabin and cockpit.

The operator's maintenance investigation found that the right air cycle machine (ACM) had leaked oil into the air conditioning system, that had then entered the cabin as smoke and fumes. The ACM turbine had seized. The Chief Engineer reported that the company conducted a fleet wide analysis to see if a failure trend could be identified for the ACM units. They determined that the Metro fleet had used a total of ten ACM's since 1999, with six being used by the incident aircraft alone. The usage was evenly distributed between left and right installations of the units. The conclusion was that the air delivery system to the ACM's might have a partial blockage leading to the premature failures.