Weather related event - VH-NGX, Southern Cross (ALA), Western Australia, on 1 June 2010

On 1 June 2010, a Fairchild Industries Inc. SA226-TC (Metro II) aircraft, registered VH-NGX, was being prepared for a charter passenger service from Perth to the Southern Cross aeroplane landing area (ALA), Western Australia (WA).

Prior to departing, the crew obtained the weather forecasts for the flight. The area forecast (ARFOR), which covered a large area, forecast fog, while the aerodrome forecast (TAF), which covered a particular location, forecast conditions as clear. The crew contacted the Bureau of Meteorology (BoM) to confirm the conditions. The crew received an amended forecast for Southern Cross indicating fog, and visibility reducing to 300 m until 0800 Western Standard Time; after this time conditions were forecast to improve.

Due to the payload requirements of the flight, additional fuel for an alternate aerodrome could not be carried as required if the weather conditions at Southern Cross were unfavourable. Consequently, the crew elected to delay the departure from Perth until 0800.

While en route, the crew observed a band of cloud between Perth and Southern Cross. On arrival at Southern Cross, the conditions were not as expected by the crew, with overcast low cloud and fog present. The crew tracked to the north of the airstrip, where the fog had cleared, and commenced the approach. In order to remain clear of cloud and maintain visual sight with the runway, the aircraft was descended to 337 ft above ground level (AGL). From this point, the crew determined that a straight-in-approach could not be conducted and a low level circling approach to position the aircraft on final for runway 14 was performed. The aircraft landed at about 0915 without further incident.

The BoM conducted a review of this incident and made a number of recommendations, including making forecasters aware of the synoptic conditions behind this incident and its consequential effect on users; and as part of a national review, establishing the minimum observation requirements needed in order to issue and maintain a weather watch on a TAF.