{"id":"F2005L03699","name":"CASA 490/05 - Designation of airspace for broadcast requirements - aerodromes with certified air/ground radio services","slug":"casa-490-05-designation-of-airspace-for-broadcast-requirements-aerodromes-with-certified-air-ground-","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":39366,"registerId":"commonwealth-F2005L03699-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"CASA 490/05 - Designation of airspace for broadcast requirements - aerodromes with certified air/ground radio services","content":"CASA 490/05 – Designation of airspace for broadcast requirements – aerodromes with certified air/ground radio services\n\nas amended\n\nmade under paragraph 99A (1) (b) and subregulation 99A (3) of the Civil Aviation Regulations 1988.\n\nThis compilation was prepared on 12 August 2021 taking into account amendments up to instrument CASA 51/21 – CASA 490/05 Amendment Instrument 2021 (No. 2). It is a compilation of CASA 490/05 – Designation of airspace for broadcast requirements – aerodromes with certified air/ground radio services, as amended and in force on 12 August 2021.\n\nPrepared by the Advisory and Drafting Branch, Legal, International and Regulatory Affairs Division, Civil Aviation Safety Authority, Canberra.\n\nCompilation No. 4.\n\nDesignation of airspace for broadcast requirements — aerodromes with certified air/ground radio services\n\n2 Designation of broadcast areas\n\nEach area of airspace within the horizontal and vertical limits defined for the area (a designated area) in Schedule 1 is designated as an area in which broadcast requirements apply.\n\n3 Direction of broadcast requirements\n\nThe broadcast requirements mentioned in Schedule 2 apply in each designated area.\n\n4 Direction of radio frequencies\n\nBroadcasts in a designated area must be made on the radio frequency mentioned in Schedule 3 for the area.\n\nSchedule 1 Limits of areas of airspace in which broadcast requirements apply\n\n1 Horizontal limits\n\n(1) In this Schedule, the horizontal limits of a designated area are defined as a circle with a radius of a stated length in nautical miles centred on a specified point.\n\n(2) If horizontal limits of a designated area are defined as mentioned in subclause (1), the circumference of the circle makes up the horizontal limits of the area.\n\n2 Vertical limits\n\n(1) In this Schedule, the vertical limits of a designated area are defined as 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.\n\n3 Designated areas\n\nYAYE/AYERS ROCK\n\nHorizontal limits: a circle of 20.0NM radius centred on\n\n25 11 10S 130 58 32E (YAYE/AD)\n\nVertical limits: 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.\n\nSchedule 2 Broadcast requirements for designated areas\n\n1 Aircraft flying through a designated area without landing\n\nThe pilot in command of an aircraft intending to fly through the area without landing must, immediately after the aircraft enters the area, make a broadcast that includes the following information:\n\n(a) the aircraft’s callsign and type;\n\n(b) the aircraft’s position;\n\n(c) the aircraft’s present level;\n\n(d) the pilot’s intentions in relation to the flight.\n\n2 Aircraft intending to land at an aerodrome in a designated area\n\nThe pilot in command of an aircraft intending to land at an aerodrome in the area, must:\n\n(a) immediately after the aircraft enters the area, make a broadcast that includes the following information:\n\n(i) the aircraft’s callsign and type;\n\n(ii) the aircraft’s radial, bearing or quadrant from, and distance from, the aerodrome at which the pilot proposes to land;\n\n(iii) the aircraft’s altitude;\n\n(iv) the pilot’s intentions in relation to the flight; and\n\n(b) if and when the aircraft joins the circuit, make a broadcast that consists of:\n\n(i) the aircraft’s callsign and type; and\n\n(ii) a statement that the aircraft is joining the circuit; and\n\n(iii) the segment in which the aircraft is joining the circuit; and\n\n(c) if the pilot intends to make a straight in approach to the landing runway, make a prior broadcast of that intention.\n\n3 Aircraft taking off from an aerodrome in a designated area\n\nThe pilot in command of an aircraft who is taxiing for take\\-off from the aerodrome must:\n\n(a) when starting to taxi, make a broadcast that includes the following information:\n\n(i) the aircraft’s callsign and type;\n\n(ii) if the proposed flight is to be conducted under the I.F.R. — a statement to that effect;\n\n(iii) the name of the aerodrome;\n\n(iv) either:\n\n(A) the proposed flight’s intended destination; or\n\n(B) the direction in which the pilot intends to fly from the aerodrome;\n\n(v) the runway proposed to be used for take\\-off; and\n\n(b) immediately before entering the runway to be used for take\\-off, make a broadcast that consists of:\n\n(i) the aircraft’s callsign and type; and\n\n(ii) the runway identifier; and\n\n(iii) a statement that the aircraft is entering the runway.\n\nSchedule 3 Radio frequencies\n\n| Broadcast area | Radio frequency (MHz) |\n| -------------- | --------------------- |\n| Ayers Rock | 126.9 |\n\n> Note to CASA 490/05 – Designation of airspace for broadcast requirements – aerodromes with certified air/ground radio services\n\n> Note: CASA 490/05 – Designation of airspace for broadcast requirements – aerodromes with certified air/ground radio services (in force under paragraph 99A (1) (b) and subregulation 99A (3) of the Civil Aviation Regulations 1988) as shown in this compilation is amended as indicated in the tables below.\n\n> Note: > Note: Table of instruments\n\n| Title | Date of FRLI registration | Date ofcommencement | Application, saving ortransitional provisions |\n| ------------------------------------------------------------------------------------------------------------------- | --------------------------------- | ------------------- | --------------------------------------------- |\n| CASA 490/05Designation of airspace for broadcast requirements — aerodromes with certified air/ground radio services | 24 November 2005(see F2005L03699) | 24 November 2005 | — |\n| CASA 72/18 —CASA 490/05 Amendment Instrument 2018 (No. 1) | 26 October 2018(see F2018L01483) | 27 October 2018 | — |\n| CASA 88/19 —CASA 490/05 Amendment Instrument 2019 (No. 1) | 5 November 2019(see F2019L01425) | 7 November 2019 | — |\n| CASA 04/21 —CASA 490/05 Amendment Instrument 2021 (No. 1) | 25 January 2021(see F2021L00068) | 28 January 2021 | — |\n| CASA 51/21 –CASA 490/05 Amendment Instrument 2021 (No. 2) | 12 August 2021(see F2021L01096) | 12 August 2021 | — |\n\n> Note: > Note: Table of amendments\n\n```html\n

ad. = added or inserted am. = amended rep. = repealed rs. = repealed and substituted

Provision affected

How affected

s. 1

rep. Legislation Act 2003, s. 48D

Schedule 1

am. F2018L01483; F2019L01425; F2021L00068; F2021L01096

Schedule 3

am. F2018L01483; F2019L01425; F2021L01096

\n```","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"The instrument maintains its original narrow purpose: designating specific aerodrome airspace for broadcast requirements. While the specific aerodromes listed in the schedules have changed over time through amendments (adding/removing airports), the fundamental scope—regulating radio broadcasts in defined areas around certified air/ground radio aerodromes—has remained consistent since 2005."},"complexity_factors":["Short, focused instrument with only 4 operative sections plus 3 schedules","Minimal defined terms (only standard aviation terminology like 'circuit', 'I.F.R.', 'radial')","Straightforward conditional structure: if in designated area → follow Schedule 2 requirements","No nested exceptions or complex cross-referencing beyond the three schedules","Schedules contain simple tabular data (frequencies) and geographic coordinates","Amendment history table adds administrative complexity but doesn't affect operative provisions"],"plain_english_summary":"This is a Civil Aviation Safety Authority (CASA) instrument that sets **radio broadcast rules for pilots flying near certain Australian airports**.\n\n**What it does:**\n- **Designates specific areas of airspace** around particular aerodromes (airports) where pilots must make radio broadcasts\n- Currently covers **Ayers Rock Airport (YAYE)** with a 20 nautical mile radius around the airport\n- Requires pilots to announce their position, intentions, and movements on a specific radio frequency (126.9 MHz for Ayers Rock)\n\n**Who it affects:**\n- **Pilots** flying through or operating near designated aerodromes with certified air/ground radio services\n- Specifically applies to:\n - Aircraft flying through the area without landing\n - Aircraft intending to land at the aerodrome\n - Aircraft taking off from the aerodrome\n\n**What pilots must do:**\n- **When entering the area:** Announce callsign, aircraft type, position, altitude, and intentions\n- **When joining the traffic pattern (circuit):** Announce joining the circuit and which segment\n- **When taxiing for take-off:** Announce callsign, type, destination/direction, and runway\n- **Before entering the runway:** Announce callsign, runway, and intention to enter\n\n**Why it matters:**\nThese rules prevent mid-air collisions by ensuring all pilots in the area know where other aircraft are and what they're doing. This is especially important at busier regional airports where there may not be full air traffic control, but there is a certified ground radio service to monitor communications.\n\nThe instrument operates under the **Civil Aviation Regulations 1988** and has been updated several times since 2005 to adjust which aerodromes are covered and their specific requirements."},"flash_summary_failed":{"failed":true,"reason":"A positive credit balance is required for all requests, including BYOK, so fallback providers remain available. Add credits at https://vercel.com/d?to=%2F%5Bteam%5D%2F%7E%2Fai%3Fmodal%3Dtop-up to continue.","source":"analysis-cron"},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The instrument remains narrowly focused on designating airspace around a certified aerodrome and prescribing required broadcasts and the radio frequency for that area. Amendments noted in the compilation (updates to Schedule 1 and Schedule 3 across several amendment instruments) appear to be technical updates to the designated area parameters or frequency details rather than an expansion of the instrument's core purpose. There is no material broadening beyond the original intent of imposing broadcast requirements in a designated aerodrome area."},"complexity_factors":["Short instrument: core rules are contained in 3 primary operative clauses (ss.2–4) plus 3 Schedules","Schedule 2 contains three operational scenarios with nested subclauses (Schedule 2.1, 2.2(a–c), 2.3(a–b))","Single designated area listed (Ayers Rock) — low geographic scope reduces complexity","One radio frequency prescribed (Schedule 3) — limits cross-frequency rules","Ambiguous phrasing in vertical limits: 'any height ... at which an aircraft may conflict' (Schedule 1, cl.2) requires interpretive judgment","Cross-reference to Civil Aviation Regulations (made under paragraph 99A(1)(b) and subregulation 99A(3)) but otherwise few external cross-references"],"plain_english_summary":"**What this instrument does (mechanically)**\n\n- Designates a specific area of airspace around Ayers Rock (YAYE) in which mandatory radio broadcasts are required. The horizontal area is a circle of 20.0 nautical miles radius centred on the coordinates 25°11'10\"S 130°58'32\"E (Schedule 1). The vertical limits are from ground level up 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” (Schedule 1, cl.2).\n\n- Directs that the broadcast requirements set out in Schedule 2 apply in that designated area (see s.3 and Schedule 2).\n\n- Requires that broadcasts be made on the radio frequency listed for the area in Schedule 3 (s.4; Schedule 3 lists Ayers Rock — 126.9 MHz).\n\n- Specifies exactly what pilots must broadcast in three common operational situations (Schedule 2):\n - Passing through the area without landing (Schedule 2.1): upon entry the pilot must broadcast callsign and aircraft type; position; present level (altitude); and intentions.\n - Intending to land at the aerodrome (Schedule 2.2): on entry the pilot must broadcast callsign/type; radial/bearing/quadrant and distance from the aerodrome; altitude; and intentions. Additional broadcasts are required when joining the circuit (callsign/type; statement that joining the circuit; which circuit segment) and prior notification is required for a straight-in approach.\n - Taking off from the aerodrome (Schedule 2.3): when starting to taxi the pilot must broadcast callsign/type; if the flight will be IFR (instrument flight rules); aerodrome name; destination or intended departure direction; and proposed departure runway. Immediately before entering the runway the pilot must broadcast callsign/type; runway identifier; and that the aircraft is entering the runway.\n\n**Who is affected**\n\n- Primary: pilots (pilot in command) operating aircraft that will fly through, land at, or take off from the designated Ayers Rock area. The duty to speak and the information required are imposed on the pilot in command (Schedule 2).\n\n- Secondary: air-ground radio services and other airspace users who monitor the frequency (aircraft, aerodrome operators), since they receive the required broadcasts and may alter behaviour accordingly.\n\n**Why it matters (stated purpose and practical effect)**\n\n- The instrument’s stated operational effect is to create a small controlled regime around a certified aerodrome in which routine position, intent and traffic information must be broadcast on a specified frequency (s.2–4; Schedule 2). The practical effect is to increase shared situational awareness for aircraft operating in that 20 NM circle by making key information compulsory and channelled to a single frequency (Schedule 3).\n\n**Compliance costs, incentives and operational trade-offs**\n\n- Who pays: pilots and operators bear the direct compliance cost (time on radio, training, checklist updates) because pilots must make the broadcasts and ensure equipment is tuned to the prescribed frequency (Schedule 2; s.4).\n\n- Behavioural incentives: the instrument encourages pilots to announce position and intentions on entry and at critical points (joining the circuit, entering runway). That makes traffic intentions more visible to others and can reduce some kinds of conflict risk, but it also creates radio-traffic that must be managed on a single frequency (Schedules 2–3).\n\n- Opportunity costs and substitution: operators may alter routes, altitudes or flight plans to avoid the designated area and the associated broadcast requirement if radio congestion or operational delay is a concern (the vertical limit wording may affect how high avoidance is required — Schedule 1, cl.2).\n\n- Information and privacy: required broadcasts include callsign, position and intentions. That improves transparency between aircraft but also discloses operational details to any listener on the frequency.\n\n**Implementation risks and points that create uncertainty or need operational judgment**\n\n- The vertical limit is defined by a performance-style phrase — \"any height above the designated aerodrome at which an aircraft may conflict with another aircraft...\" (Schedule 1, cl.2). That requires interpretation in practice (what heights are considered relevant depends on aircraft types and local procedures) and could cause uncertainty for high-altitude overflights unless clarified in local guidance.\n\n- Single-frequency operation (126.9 MHz) concentrates all broadcasts on one channel (s.4; Schedule 3). If traffic increases, the frequency could become congested, creating a risk of missed calls or overlapping transmissions.\n\n**Concentrated benefits and diffuse costs**\n\n- Concentrated benefits: aerodrome operators, local traffic and pilots using the aerodrome gain predictable position and intent information from mandatory broadcasts (Schedule 2).\n\n- Diffuse costs: every pilot transiting the area must comply, regardless of whether they land, which creates a small recurring communication and training burden for a broad set of operators (Schedules 2.1–2.3).\n\n**Net operational effect (mechanical summary)**\n\n- Pilots entering the 20 NM circle must switch to 126.9 MHz and make specified position/intention broadcasts at prescribed times. The rule standardises who says what and when, and mandates a single frequency for those communications (s.2–4; Schedules 1–3)."}},"importantCases":[],"_links":{"self":"/api/acts/casa-490-05-designation-of-airspace-for-broadcast-requirements-aerodromes-with-certified-air-ground-","history":"/api/acts/casa-490-05-designation-of-airspace-for-broadcast-requirements-aerodromes-with-certified-air-ground-/history","analysis":"/api/acts/casa-490-05-designation-of-airspace-for-broadcast-requirements-aerodromes-with-certified-air-ground-/analysis","conflicts":"/api/acts/casa-490-05-designation-of-airspace-for-broadcast-requirements-aerodromes-with-certified-air-ground-/conflicts","importantCases":"/api/acts/casa-490-05-designation-of-airspace-for-broadcast-requirements-aerodromes-with-certified-air-ground-/important-cases","documents":"/api/acts/casa-490-05-designation-of-airspace-for-broadcast-requirements-aerodromes-with-certified-air-ground-/documents"}}