Why have the airspace boundaries associated with operations at non-towered aerodromes been removed?
The previous system of radio communication boundaries simply didn’t work. Figures from the Civil Aviation Safety Authority (CASA) show VFR non-compliance with mandatory broadcasts averaged at 3.5 per cent and was as high as 32.3 per cent at some aerodromes. A survey conducted by the National Airspace System Implementation Group (NASIG) of 1500 pilots – 50 per cent private VFR, 25 per cent commercial and 10 per cent air transport or IFR – showed that only six per cent believed all pilots made the required MBZ calls. Despite these figures, there had never been a prosecution for radio non-compliance in an MBZ. Further, having strictly defined volumes of airspace around non-towered aerodromes, as was the case in Australia, created an expectation that everyone in the airspace was on the same radio frequency – when that was not always the case. Previously, Australian non-towered aerodromes operated using three different sets of procedures MBZs and CTAFs and Multicoms. In the case of MBZs and
