Operational non-compliance involving a British Aerospace PLC BAe 146-100, VH-NJE, 65 km north-west of Morawa (ALA), Western Australia, on 2 October 1996

The aircraft planned to track from Karratha to Perth via Morawa. This track used the Karratha navigation aids and the Morawa non directional beacon (NDB) as the only aids for more that 500 NM. The Morawa NDB has a rated coverage of 50 NM. As the aircraft was not fitted with area navigation systems, it relied solely on off-set fixes from navigation aids not on track to supplement the information from the two on-track aids. The aircraft had previously experienced tracking difficulties on the route, and these were exacerbated by the known interference between the Morawa NDB and Laverton NDB. The Laverton NDB has the same frequency as the Morawa NDB. A computational error by the crew, associated with an unexpected wind shift, combined with the deficient tracking aids to cause the aircraft to deviate from the required track.

Since the incident, the operating company has directed that any of its aircraft without area navigation systems are to track on routes that pass over navigation aids which provide accurate enroute tracking information.