CASA 490/05 - Designation of airspace for broadcast requirements - aerodromes with certified air/ground radio services

The central concept is the “designated area” as defined in Schedule 1. Its horizontal limits are a circle of 20.0 nautical miles radius centred on the YAYE aerodrome reference point. The vertical limits are not a fixed altitude ceiling: they extend from ground level to “any height above the designated aerodrome at which an aircraft may conflict with another aircraft that is arriving, departing, or carrying out local operations, at the aerodrome.” This creates a dynamic upper boundary that depends on actual traffic and operational circumstances. The pilot must assess whether conflict is possible, which introduces a degree of subjective judgment. The “broadcast requirements” are the mandatory radio transmissions set out in Schedule 2. They are split into three categories. For an aircraft flying through without landing, the pilot must broadcast callsign, type, position, present level, and intentions “immediately after the aircraft enters the area.” For an aircraft intending to land, the pilot must broadcast radial, bearing or quadrant from the aerodrome, distance, altitude, and intentions immediately after entry; additionally, if joining the circuit, a broadcast of callsign, type, and the joining segment is required; and a prior broadcast is required if planning a straight-in approach. For an aircraft taking off, the pilot must broadcast when starting to taxi (callsign, type, IFR statement if applicable, aerodrome name, destination or direction, intended runway), and immediately before entering the runway (callsign, type, runway identifier, and a statement that the aircraft is entering the runway). The instrument also defines the radio frequency: 126.9 MHz for Ayers Rock. Although the title mentions “certified air/ground radio services,” that concept is not defined in this instrument; it appears in the enabling provision CAR 99A, which requires that the aerodrome have such a service for the airspace to be designated. The instrument thus operates as a layer of procedural communication on top of the existing airspace classification, requiring all aircraft in the area to self-announce on a common frequency.

The instrument directly affects every pilot in command of an aircraft that enters the designated area around Ayers Rock Aerodrome. That includes private recreational pilots, commercial charter operators, scenic flight operators, general aviation traffic transiting the area, and possibly military aircraft unless exempted by other legislation. The instrument does not distinguish by aircraft type, weight, or purpose; any aircraft entering the airspace is captured. The three categories in Schedule 2 cover all operational modes: overflight (flying through without landing), arrivals (intending to land), and departures (taking off from the aerodrome). Pilots of aircraft that are taxiing for take-off must broadcast both when starting to taxi and immediately before entering the runway. This means that even a small single-engine piston aircraft doing a quick turn-around must comply with both broadcasts. The instrument also affects the operators of the certified air/ground radio service at YAYE, though not directly: the designation presupposes that such a service exists, and pilots will be broadcasting on a frequency that may be monitored by that service or by other aircraft. Passengers are not directly affected, but they bear the indirect cost of increased pilot workload and potential delays while broadcasts are made. The instrument imposes uniform compliance costs on all pilots: they must have a functioning radio capable of transmitting on 126.9 MHz, they must know the designated area boundaries, and they must allocate time and attention to making the prescribed broadcasts. For pilots unfamiliar with the area, the dynamic vertical limit adds a burden of judgment. There is no exception for aircraft without radios (e.g. gliders, ultralights) - those aircraft would be unable to comply, raising a practical issue. The instrument currently affects only one aerodrome, but CASA could amend Schedule 1 to add other aerodromes with certified air/ground radio services at any time, expanding the regulatory reach.

The instrument imposes duties but confers no explicit rights on pilots. The duties are set out in Schedule 2 with precise triggering events. For an aircraft flying through without landing: the duty is to broadcast the specified information immediately after entering the area. Timing is strict; a delayed broadcast may constitute non-compliance. For an aircraft intending to land: there is a primary duty to broadcast immediately after entry, supplemented by conditional duties to broadcast when joining the circuit and to broadcast prior to a straight-in approach. The circuit-joining broadcast must include the segment (e.g. “joining downwind”), and the straight-in approach broadcast must be “prior.” For an aircraft taking off: there are two separate duties. The first duty is triggered when starting to taxi, and requires a broadcast that includes destination or direction of flight and the intended runway. The second duty is triggered immediately before entering the runway for take-off, and requires a broadcast of callsign, type, runway identifier, and a statement of entering the runway. The instrument does not require the pilot to listen to the frequency or to acknowledge other traffic broadcasts, though good airmanship would dictate that. The instrument also does not impose a duty to rebroadcast if intentions change after the initial broadcast; however, safe practice would suggest updating if the change affects traffic. The frequency use is a duty; broadcasts must be on 126.9 MHz for Ayers Rock; using a different frequency would breach section 4. There is no right to be exempted from the broadcast requirements, even if the pilot is in contact with air traffic control (though if there is ATC, the airspace would likely be controlled, not designated as a broadcast area). The instrument also does not provide for a waiver or alternative compliance method. A pilot who cannot broadcast due to radio failure must decide whether to avoid the area or proceed at risk of enforcement. The vertical limits definition gives pilots a duty to assess whether their aircraft may conflict - that is a judgment call that must be made honestly.

The instrument itself does not prescribe specific penalties. It is made under CAR 1988 sections 99A(1)(b) and 99A(3). The parent regulation, CAR 99A, empowers CASA to designate airspace and direct broadcast requirements; a contravention of a direction given under that regulation is likely an offence under the Civil Aviation Regulations. Regulation 299 of CAR 1988 (as in force) is a common penalty provision for breaches of regulations, carrying a maximum penalty of 50 penalty units (currently $9,125) for an individual and 250 penalty units for a body corporate. However, the instrument does not refer to any specific penalty provision. Enforcement is carried out by the Civil Aviation Safety Authority (CASA). CASA may take administrative action such as issuing a direction, suspending or cancelling a pilot licence or certificate, or imposing enforceable undertakings. The instrument is a legislative instrument registered on the Federal Register of Legislation, so non-compliance is a civil penalty or criminal offence depending on how the parent regulation characterises the breach. Because the broadcast requirements are prescriptive and triggered by objective events (entry, taxi, joining), proving a breach would typically involve witness testimony, flight data, or recorded broadcasts. The vertical limits definition is less objective and could be harder to enforce: a pilot might argue that their altitude did not create a potential conflict. The absence of a fixed top introduces ambiguity that may weaken enforcement. The instrument does not create a stand-alone offence; it relies entirely on the enforcement machinery of the CAR 1988. Given the low likelihood of detection for a single missed broadcast, enforcement may depend on complaints from other pilots or an incident. The instrument is therefore primarily a mandatory standard that shapes pilot behaviour through risk of penalty, but the actual probability of enforcement is uncertain.

The instrument is subordinate legislation under the CAR 1988, which sits under the Civil Aviation Act 1988. The instrument operates within the broader framework of Australian airspace regulation. Airspace in Australia is classified under the Airspace Regulations and the Manual of Standards (MOS) Part 172; this instrument does not alter the class of airspace. Designated broadcast areas exist independently of controlled airspace. At Ayers Rock, the airspace may be Class G (uncontrolled) outside any control zone; the broadcast requirement adds a procedural layer but does not impose a requirement to obtain a clearance or to follow air traffic control instructions. If the airspace were later classified as controlled, ATC instructions would take precedence over broadcast requirements. The instrument interacts with other CASA instruments that designate broadcast areas for other aerodromes (e.g., CASA 489/05 for aerodromes without certified air/ground radio services). It specifically applies only to aerodromes with a certified air/ground radio service, which implies that the service provider is licensed under CAR 1988 Division 5 and must monitor the frequency. The instrument does not interact with state or territory laws, but Australian Noise and Flight Path Monitoring regulations may require other communications. The instrument also interacts with the pilot’s general duty under CAR 1988 regulation 229 to maintain a proper lookout and avoid collision; the broadcast requirement supports that duty but does not replace it. There is no interface with the Privacy Act 1988 or surveillance laws, as broadcasts are inherently public. The instrument also interacts with the international standards of ICAO Annex 2 (flight rules) and Annex 11 (air traffic services) through the CAR 1988, but the instrument itself is a domestic designation. If a pilot is operating under Instrument Flight Rules (IFR), the instrument requires a statement to that effect in the taxi broadcast; this interacts with the IFR clearance requirements. The instrument does not expressly override any other CASA instrument; it is additive.

The instrument was originally made on 24 November 2005 (F2005L03699) and commenced on the same day. Since then, it has been amended four times, all by later CASA amending instruments. The first amendment, CASA 72/18 (F2018L01483), was made on 26 October 2018 and commenced on 27 October 2018. It amended Schedule 1 (limits of airspace) and Schedule 3 (radio frequencies). The second amendment, CASA 88/19 (F2019L01425), was made on 5 November 2019 and commenced on 7 November 2019, again amending Schedule 1 and Schedule 3. The third amendment, CASA 04/21 (F2021L00068), was made on 25 January 2021 and commenced on 28 January 2021, amending Schedule 1. The fourth amendment, CASA 51/21 (F2021L01096), was made on 12 August 2021 and commenced the same day, amending Schedule 1 and Schedule 3. The table of amendments shows that section 1 was repealed by the Legislation Act 2003, section 48D (which automatically removed a redundant provision). The Schedule 1 amendments likely adjusted the horizontal or vertical limits, or added or removed aerodromes. The compilation as at 12 August 2021 shows only Ayers Rock as a designated area, whereas the original 2005 instrument may have included other aerodromes (such as Alice Springs or others) that have been progressively removed or replaced. The amendment history suggests that the instrument had a broader original scope that narrowed over time to a single aerodrome. Schedule 3 (frequencies) has also been amended, indicating that the assigned frequency for Ayers Rock may have changed (e.g., from 126.7 to 126.9) or that other aerodromes were removed from the schedule. The 2018 and 2019 amendments were likely made to align the instrument with updated airspace boundaries or to correct coordinates. The 2021 amendments (two in one year) may reflect operational changes such as the introduction of a new certified air/ground radio service or adjustment of the 20 NM radius. The compilation note confirms that the instrument is a compilation prepared on 12 August 2021, No. 4, meaning there have been four compilation versions. Users must always check the latest compilation on the Federal Register of Legislation, as the instrument is subject to further amendment without notice.

The source document does not mention any litigation history. There is no reference to court cases, tribunal decisions, or enforcement proceedings concerning this specific instrument. The absence of reported litigation may indicate that the instrument is not frequently challenged or that compliance is generally high. Alternatively, disputes may be resolved administratively by CASA without judicial review. It is possible that a pilot has been prosecuted for breaching the broadcast requirements under the CAR 1988, but that would appear under the parent regulation, not this instrument. The instrument itself is a procedural direction, and its validity could theoretically be challenged for unreasonableness or ultra vires, but no such challenge is recorded in the source. The instrument’s vertical limits definition (“any height … at which an aircraft may conflict”) could be subject to interpretive dispute in enforcement proceedings; however, no case law is provided. Litigation may also arise if the instrument were challenged for failing to comply with the Legislative Instruments Act (now Legislation Act) registration requirements, but the instrument is registered and compiled. The lack of litigation history is notable but does not mean the instrument is uncontroversial; it may simply mean that disputes are settled without published decisions. Practitioners should treat the instrument as unchallenged in court, but with the caveat that the dynamic vertical limit could be tested if a pilot argues it is too vague to enforce. Without specific case law, compliance risk must be assessed on the plain text.

Several aspects of this instrument may catch out the unwary pilot. First, the vertical limits are not a fixed altitude. The definition “any height above the designated aerodrome at which an aircraft may conflict with another aircraft” means there is no cap such as 5,000 feet or flight level 100. If a jet is departing Ayers Rock and climbing to, say, FL 200, an aircraft passing overhead at FL 250 might argue no conflict, but an aircraft at lower levels could conflict. The pilot must continuously assess whether a conflict is possible; if in doubt, the broadcast requirement applies. This places a burden on the pilot to judge scenarios, and different pilots might reach different conclusions. Second, the trigger for flying-through broadcasts is “immediately after the aircraft enters the area.” The area is a 20 NM radius circle. Visualising that boundary in flight without GPS is difficult; a one-nautical-mile error in position could mean the pilot broadcasts late or not at all. Third, for pilots taking off, there are two separate broadcasts: one when starting to taxi and another immediately before entering the runway. It is common for pilots to make only one broadcast on initial taxi; missing the second broadcast is a breach. Fourth, the instrument requires the taxi broadcast to include “the proposed flight’s intended destination; or the direction in which the pilot intends to fly from the aerodrome.” Note the disjunctive “or”; the pilot must choose one. But if the destination changes after taxi start, there is no duty to rebroadcast, though not doing so could mislead other traffic. Fifth, the frequency is only 126.9 MHz. Many pilots use a common frequency such as 126.7 for area broadcasts in Class G. Using 126.7 instead would violate section 4. Sixth, the instrument does not exempt aircraft with radio failure. If an aircraft cannot transmit, it technically cannot comply; the pilot must decide whether to avoid the area entirely. There is no mention of a light signal alternative. Seventh, Schedule 2 clause 2(c) requires a broadcast of intention to make a straight-in approach; this must be “prior” - the instrument does not specify how far in advance. Failure to make a timely broadcast could lead to a conflict. Eighth, the instrument does not require the pilot to listen out on the frequency, only to broadcast. A pilot who transmits but does not monitor could miss traffic broadcasts from others, increasing collision risk. Ninth, the compilation notes that Schedule 1 has been amended four times; the current coordinates for the centre point may not match older charts. Pilots must use the current coordinates (25 11 10S 130 58 32E). Tenth, the instrument applies specifically to aerodromes with a certified air/ground radio service. If that service ceases to be certified, the designation may no longer be valid, but the instrument is not self-amending; pilots cannot assume non-compliance is safe without checking current certification.

Compliance with CASA 490/05 requires that every pilot in command of an aircraft operating in the designated area around Ayers Rock follow the broadcast requirements in Schedule 2 and use the frequency in Schedule 3. The steps, determined by the nature of the flight, are as follows.

Before any flight into or out of the area, the pilot should obtain the latest compiled version of the instrument from the Federal Register of Legislation to confirm the current coordinates, limits, and frequency. The current horizontal limit is a circle of 20.0 NM radius centred on 25 11 10S 130 58 32E. The vertical limit is ground level to any height where conflict with YAYE traffic is possible; in practice, a pilot should assume the requirement applies at all altitudes within 20 NM unless certain that no conflict exists (e.g., in cruise at very high levels above all YAYE traffic). Plot the area on a chart or GPS.

For an aircraft flying through without landing: as soon as the aircraft crosses the 20 NM boundary, tune the radio to 126.9 MHz and make a broadcast stating: callsign, aircraft type, position (e.g., “10 miles north of Ayers Rock”), present level, and intentions (e.g., “transiting southbound at 8,500 feet”). Continue monitoring the frequency for the duration of the transit.

For an aircraft intending to land at YAYE: upon entering the 20 NM area, immediately broadcast: callsign, type, radial/bearing/quadrant from the aerodrome (e.g., “10 miles north of the field”), altitude, and intentions (e.g., “inbound to land”). If joining the circuit, make an additional broadcast when joining, stating callsign, type, and the segment being joined (e.g., “joining downwind runway 12”). If planning a straight-in approach, make a prior broadcast of that intention before reaching the final approach point - for example, “Ayers Rock traffic, VH-ABC, Cessna 172, 5 miles south, straight-in runway 12.” After landing, no further broadcast is required.

For an aircraft taking off from YAYE: before starting to taxi (preferably during the pre-taxi checks), tune to 126.9 MHz. When starting to taxi, broadcast: callsign, type; if IFR, “IFR”; aerodrome name; either destination (e.g., “Alien Springs”) or direction of flight (e.g., “northbound”); and the intended take-off runway. Then, immediately before entering the runway (i.e., before crossing the holding point or turning onto the runway), broadcast a second time: callsign, type, runway identifier, and “entering the runway.” The pilot should ensure this broadcast is made before actually rolling onto the runway, not while already on it.

Throughout the flight, the pilot should monitor 126.9 MHz for broadcasts from other traffic. Although the instrument does not require acknowledgement, good practice is to acknowledge if a traffic conflict is indicated. The pilot should also consider that a transmission failure means non-compliance; if the radio fails, the safest course may be to avoid the area if possible, or to proceed with extreme caution and make the broadcast if able. Record-keeping is not required by the instrument, but maintaining a flight log noting broadcast times could assist in any enforcement investigation. For recurrent operations, incorporate the broadcast procedures into standard operating checklists. If the destination or routing changes after an initial broadcast, re-broadcast the updated intentions. Finally, check for any other CASA instruments that may impose additional requirements at YAYE, such as restricted areas or noise abatement procedures.