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

1 INTRODUCTION
1.1 Background
The Australian Transport Safety Bureau (ATSB) proactively monitors aviation safety
through the analysis of accident and incident data, collectively termed occurrence
data, to determine whether important trends are emerging. In recent years, the ATSB
has received an increasing number of comprehensive occurrence reports from pilots
regarding operations at non-towered aerodromes, and the associated use of Common
Traffic Advisory Frequencies (CTAF, and formerly CTAF(R) 2 ). This report also
includes those occurrences in Mandatory Broadcast Zones (MBZs) prior to 24
November 2005.
1.1.1 What is a non-towered aerodrome?
Civil Aviation Regulation 2 defines a non-towered (also known as non-controlled)
aerodrome as an aerodrome at which an air traffic service is not operating. CASA
(2010a) further explains that this can be either:
• an aerodrome that is always in Class G airspace, including those provided with
Flight Information Service or a ground-based information service 3
• an aerodrome with a control tower where no air traffic control (ATC) service is
currently provided
• an aerodrome which would normally have ATC services, but such services are
presently unavailable.
For non-towered aerodromes which have a partial Class C or D air traffic control
service at some times of the day, operating hours are published in the current En
Route Supplement Australia (ERSA), and in any notices to airmen (NOTAMs) that
may be issued.
Under the present rules (Civil Aviation Regulation (CAR) 166), aircraft are
specifically considered to be in the vicinity of a non-towered aerodrome if they are in
uncontrolled airspace, within a horizontal distance of 10 NM (18.5 km) from the
aerodrome, and at a height above the aerodrome’s reference point that could result in
conflict with operations at the aerodrome (CASA, 2010a). This can include aircraft
overflying, transiting nearby, or arriving via a circling approach at a non-towered
aerodrome, depending on their intended flight path and other nearby traffic.
2 The CTAF(R) designation indicated that carriage and use of radio was required in the vicinity of a
non-towered aerodrome. From 3 June 2010, the CTAF(R) designation no longer applied following
changes to the regulations that govern non-towered aerodromes (CAR 166). While this report does
not analyse occurrences after 31 December 2008, more information about the current non-towered
aerodrome rules can be found in section 1.1.6. For further information on the changes to CAR 166,
contact the Civil Aviation Safety Authority (CASA), or visit their website (www.casa.gov.au).
3 See section 6.3 for more information on Flight Information Service, UNICOM, and CA/GRS
services.
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