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

RAPAC data
Information from Regional Airspace and Procedures Advisory Committee (RAPAC)
meetings was used in this report to identify issues relating to safety matters in the
vicinity of non-towered aerodromes not linked to an occurrence, such as frequency
congestion and terrain shielding, leading to radio frequency interference.
Meetings of RAPACs (which are state-based) are usually convened by the OAR, with
the frequency of meetings dependent upon on the location 15 . The Minutes of the
RAPAC meetings between July 2009 and June 2010 that were published by the OAR
on their website (via www.casa.gov.au) were reviewed in order to identify safety
issues of concern to some aerodrome users at particular aerodromes. They are
discussed further in Chapter 9.
2.2 Data limitations
Occurrence data
The nature of non-controlled airspace makes it difficult from an occurrence analysis
perspective to identify occurrences where aircraft came into close proximity with each
other, especially where aircraft operating under visual flight rules (VFR) are involved.
The inherent lack of separation service means that reports of aircraft proximity at the
time of an occurrence are often not reported, or if they are, are subjective estimates
only provided by the reporting pilot or flight crew. If the identity of the other aircraft
involved is known, the ATSB will endeavour to contact both pilots to verify what
happened, and how far apart the aircraft were.
The lack of a separation standard also introduces difficulties in defining what
constitutes an ‘incorrect presence’, and who was involved in the error that led to it.
Situations which raise the possibility of an incorrect presence include an aircraft
entering a runway while another aircraft is occupying it for the purposes of taking off
or landing, activities being undertaken on a runway by ground vehicles or personnel
while an aircraft is on approach, or an aircraft on approach to one end of a runway
while another aircraft is on approach to the reciprocal runway end.
Furthermore, there was and is likely to be underreporting of incidents, as not all of the
occurrence types selected for analysis in this report were considered to be
immediately reportable matters (IRMs) or routinely reportable matters (RRMs) at the
time of the occurrence for all operation types under the provisions of the Transport
Safety Investigation Regulations 2003, and formally under the Air Navigation Act
1920.
Minimal information exists for many of the 709 occurrences identified during the
reporting period in the vicinity of non-towered aerodromes. In over half of the
occurrences, it was not known what types of aircraft or operations were involved.
Safety factor coding for airspace-related incidents was sparse, and cannot provide a
comprehensive view of what contributes to each occurrence. Instead, error types were
coded to provide a broad means of establishing the reasons behind each occurrence,
based on the summary information provided to the ATSB at the time of notification.
A qualitative analysis of the reporter’s summary text of the occurrence was an
important component to analyse occurrence data in this report. It is important to note
15
A full schedule of RAPAC meetings for each state is provided on the CASA OAR website
(www.casa.gov.au).
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