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

What challenges do pilots face at non-towered aerodromes?
As non-towered aerodromes are by their very nature uncontrolled, there is a reliance
on pilots using them (or operating in the vicinity) to act in a safe, professional,
sensible and pragmatic manner in order to maintain separation between their aircraft
and other airspace users, including other aircraft (aeroplanes, helicopters, gliders,
balloons) or parachutists. For this reason, specific non-towered aerodrome procedures
exist to maintain order in the air, and improve the situational awareness of all pilots.
Operations at non-towered aerodromes can present challenges to pilots that they
might not encounter when operating to some aerodromes where an ATC service is
provided. These can include:
• different operating procedures that are specific to non-towered aerodromes
• fitting into the circuit traffic
• communicating with other aircraft to arrange separation
• a mixture of aircraft types, operation types, and performance levels
• dealing with threats and hazards that might be encountered, such as unannounced
traffic, or unexpected manoeuvres by nearby aircraft.
Over the course of this study, two regimes of non-towered aerodrome procedures
have applied. Prior to 24 November 2005, non-towered aerodromes were surrounded
by defined volumes of airspace called CTAF areas (radio carriage and use not
required) or MBZ areas 4 (radio required) in which non-towered aerodrome
procedures applied. In MBZ areas, positional broadcasts were required to be made
on
the assigned MBZ frequency. As part of the introduction of the National Airspace
System (NAS) Stage 2C, CTAFs and MBZs were abolished from 24 November 2005,
and replaced with a common, standardised set of procedures that applied to all non-
towered aerodromes.
When MBZs were abolished in 2005, pilots were still expected to adhere to the nontowered
aerodrome procedures and maintain separation within the vicinity of all nontowered
aerodromes (within 10 NM) by monitoring and broadcasting on the assigned
CTAF or CTAF(R) frequency . Only pilots flying radio-equipped aircraft were
allowed to operate in the vicinity of aerodromes that were designated as CTAF(R) 5 .
4 MBZs were first introduced in December 1995, following a legislative name change from Mandatory
Traffic Advisory Frequency (MTAF) areas. The change resulted from a desire to highlight and
reinforce the mandatory requirements to make certain radio broadcasts. While the majority of
MTAFs became MBZs, some areas were changed to other airspace procedures, including CTAFs.
There were no major procedural alterations association with the name change from MTAFs to MBZs
(ATSB, 2006a).
5 From 3 June 2010, pilots must both be equipped with a radio and be appropriately trained and
qualified to use it before operating at all certified, registered, military, or other specified non-towered
aerodromes. The appropriate licence must be issued or recognised by CASA. Licensing requirements
are specified in CAR 166.
- 2 -