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

ATS errors in passing traffic information to IFR aircraft transiting through
uncontrolled airspace in the vicinity of non-towered aerodromes, or aircraft operating
onto closed runways in breach of a current notice to airmen (NOTAM).
4.4 Making your presence and intentions known
As aviation has developed, increasing performance, traffic density, and flight in nonvisual
conditions has limited the effectiveness of total reliance on the ‘see-and-avoid’
principle for maintaining safe margins of separation between aircraft (see BASI
(1991) for a comprehensive review of the limitations of see-and-avoid). The need to
enhance situational awareness of pilots, particularly where no ground-based air traffic
control and/or information service is provided, has led to the principle of ‘alerted seeand-avoid’.
Radio is the primary tool of ‘alerted see-and-avoid’ common across aviation from
sport and recreational flying to air transport. Radio allows for the communication of
information (in this instance traffic information) to the pilot from the ground (air
traffic control or an air-ground radio operator) or other aircraft (CASA, 2010b). Other
tools of ‘alerted see-and-avoid’ include ground radar, automatic dependent
surveillance broadcast (ADS-B), and Traffic Collision Avoidance System
(TCAS/ACAS).
Previous ATSB research has found that the effectiveness of a search for other traffic
is eight times greater under alerted see-and-avoid circumstances compared to unalerted
(BASI, 1991). For this reason, CASA has developed a standard phraseology
and set of basic, common positional broadcasts that pilots should make on the CTAF
when operating into, out of, over, and in the vicinity of non-towered aerodromes.
Pilots should always carry a radio and learn how to use it correctly, irrespective of
whether they are flying into a registered/certified aerodrome or not.
The intent of CASA specifying minimum level of broadcasts and a standard
phraseology is to improve situational awareness for all pilots operating in the vicinity
of any particular non-towered aerodrome. These broadcasts and the appropriate
phraseology are specified in Civil Aviation Regulation (CAR) 166C and the
Aeronautical Information Publication (AIP), and also in the supporting Civil Aviation
Advisory Publications (CAAPs).
Changes to recommended broadcasts since 3 June 2010
The recommendations for broadcasts when operating at or near a non-towered
aerodromes changed on 3 June 2010. Since the introduction of the National Airspace
System (NAS) 2C procedures in November 2005, CASA has conducted a postimplementation
review process of the procedures in order to refine and optimise
broadcast and radio carriage requirements in the interests of operational efficiency
and safety.
While CASA no longer defines any mandatory broadcasts in the circuit, there are six
recommended broadcasts that pilots are expected to make covering departing and
approaching a non-towered aerodrome and joining the circuit. An additional broadcast
is suggested for pilots conducting instrument approaches.
These changes have been made by CASA in the interests of providing pilots with
more flexibility about making the broadcasts that they deem necessary. The intention
is to improve operations at non-towered aerodromes, and improve situational
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