Safety in the vicinity of non-towered aerodromes - Australian ...

10.2 Previous ATSB studies into non-towered aerodrome
safety
It was not possible to draw firm conclusions about the difference in findings between
the two previous ATSB reports into occurrences at MBZs, and the findings presented
here. This report considers all airspace use and procedural-related issues at nontowered
aerodromes, rather than specifically at those where MBZ and CTAF
procedures have applied.
Furthermore, this report does not compare the perceived level of safety between
CTAF and CTAF(R)/MBZ aerodromes. This topic has been studied in significant
detail by the Civil Aviation Safety Authority (CASA) Office of Airspace Regulation
(OAR) in their CTAF versus CTAF(R) study, conducted by The Ambidji Group in
August 2008. The findings of that study (and the post-implementation review of the
National Airspace System (NAS) 2C introduction) supported the change to the
requirement for mandatory radio carriage and use at all certified, registered, military,
and other designated non-towered aerodromes from 3 June 2010.
There were some common themes in the analysis of 709 occurrences between 2003
and 2008 presented here, and the previous MBZ reports published by the ATSB (2003
and 2006):
• Approximately two airspace-related occurrences occurred in the vicinity of a nontowered
aerodrome and were reported to the ATSB each week, and this has
remained the case since 1994.
• Passenger transport aircraft were involved in a large proportion of the occurrences;
however, this was likely to be due to more active reporting behaviours rather than
an increased risk within this sector.
• Radio communication issues and reduced situational awareness due to pilots not
broadcasting or not following the standard broadcast procedures were the most
common factors contributing to airspace-related occurrences.
• The rate of occurrences remains low across all individual non-towered aerodromes.
• The number of occurrences reported to the ATSB at non-towered aerodromes
remains small as a proportion of all occurrences reported to the ATSB over the
reporting period.
A change was noted since the 2003 report regarding the non-towered aerodromes that
recorded the greatest number of airspace-related occurrences. Between 1994 and
2003, Bundaberg, Ayers Rock, Devonport, and Jandakot had the highest number of
reported occurrences. Between 2003 and 2008, the most occurrences were reported at
Newcastle, Avalon, Geraldton, and Dubbo.
The quality of the occurrence data recorded for airspace-related occurrences has
increased in recent years, making comparisons with historical data difficult. This has
been driven by improved aviation safety legislation and a greater level of prescribed
reporting since 1 July 2003 under the Transport Safety Investigation Act 2003,
compared to its predecessor, the Air Navigation Act 1920. The ATSB’s Aviation
Statistics and biannual Australian Aviation Safety in Review publications indicate
that reporting rates for aviation accidents and incidents have increased since this time.
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