Australian air traffic control union Civil Air has renewed calls for the government to suspend its airspace modernisation after an incident involving a Virgin Blue Boeing 737-400 and a Cessna 421 near Melbourne last week. The calls come as the air traffic services provider accuses the union of distorting the facts about safety incidents.

In the incident, on 3 December, the crew of the 737 received a resolution advisory (RA) from the aircraft's traffic collision avoidance system (TCAS) when separation was lost with the Cessna 421 as the 737 descended. An air ambulance was nearby but not involved, says air traffic services provider Airservices Australia, and all aircraft were known to air traffic control.

Civil Air says the incident is a result of the latest stage of the National Airspace System (NAS), which introduces Class E airspace and a greater reliance on see-and-avoid procedures. The union claims the 737 and Cessna were 20s from a mid-air collision. Airservices says it is too early release details. It adds that TCAS RAs are not irregular and a spate of separation breakdowns earlier this year, before the implementation of NAS, prompted an investigation. Airservices and the Australian Transportation Safety Bureau are examining this incident.

Civil Air says NAS reduces safety standards and claims that in its first few days there were more than 20 incidents involving light aircraft straying into major city flightpaths. Aircraft flying above 10,000ft (3,000m) must have transponders, but the union says controllers are reporting around four transponder failures an hour, while pilots are using incorrect frequencies, as maps no longer provide frequency information.

Airservices chief executive Bernie Smith accuses Civil Air of a "gross distortion of the facts". Airservices is investigating nine incidents in NAS airspace, the bulk of them not serious safety occurrences.

Source: Flight International