EMMA KELLY / PERTH
Australia's Civil Aviation Safety Authority (CASA), Airservices Australia and the National Airspace System Implementation Group (NAS IG) are reviewing the controversial NAS in light of the Australian Transport Safety Bureau (ATSB) identifying an event in the redesigned airspace late last year as a "serious incident" or airprox. The ATSB recommends that NAS procedures and communications requirements for operations in Class E airspace are reviewed.
The latest elements of NAS - including Class E airspace replacing large parts of Class C and G airspace, removal of frequencies from charts and mandatory transponder carriage and use - were introduced in late November. The changes have been criticised by air traffic controllers and pilots and blamed for a number of incidents.
The incident that prompted the review involved a Virgin Blue Boeing 737-700 and an EADS Socata Tobago, 19km (10nm) off Launceston, Tasmania, flying in Class E airspace on 24 December. The 737 was on an instrument flight rules descent through 8,300ft (2,530m) when its traffic collision avoidance system (TCAS) was triggered by the Tobago travelling under visual flight rules at 7,500ft in the opposite direction. The 737 climbed to 9,200ft.
TCAS indicated the Tobago passed the 737 within 200ft vertically and less than 1nm horizontally. The ATSB says that the aircraft came into such close proximity that the action of the 737 crew "may have averted a mid-air collision".
The ATSB says that procedures and communications requirements for operations in Class E airspace must be reviewed to enhance situational awareness.
Source: Flight International
