Parts 91, 121, 133 and 135 Manuals of Standards Amendment Instrument 2026

Replacement Explanatory Statement

Civil Aviation Safety Regulations 1998

Parts 91, 121, 133 and 135 Manuals of Standards Amendment Instrument 2026

Purpose

The purpose of the Parts 91, 121, 133 and 135 Manuals of Standards Amendment Instrument 2026 (the instrument) is to amend the Parts 91, 121, 133 and 135 Manuals of Standards (the relevant MOSs) to ensure that radio altimeters fitted to aircraft that are used for low-visibility approaches in Australian territory comply with specified requirements. The instrument is required because the most recent of the fifth-generation (5G) wireless broadband systems in Australia are licensed to operate in a frequency band (3.7 – 4.0 GHz) that is near to the radio altimeter frequency band (4.2 – 4.4 GHz). Studies have shown that 5G transmissions in this band can interfere with the operation of radio altimeters. This issue is also faced by other National Aviation Authorities. The approach to this issue taken by the Civil Aviation Safety Authority (CASA) is consistent with the approach taken by the Federal Aviation Administration of the United States of America (FAA).

The instrument amends the Parts 121, 133 and 135 Manuals of Standards so that aircraft operators must ensure that each radio altimeter fitted to an aeroplane or rotorcraft used for low-visibility approaches at Australian aerodromes meets the requirements for tolerance to radio frequency interference set out in a specified FAA Airworthiness Directive (AD) that applies for the kind of aircraft. A similar requirement is imposed on the pilot in command under the Part 91 Manual of Standards (the Part 91 MOS).

The requirements will commence on 1 April 2026. This is because interim measures imposed by the Australian Communications and Media Authority (ACMA) to mitigate the effects of 5G transmissions on radio altimeters around airports are scheduled to end on 31 March 2026.

Legislation

Under section 9 of the Civil Aviation Act 1988 (the Act), CASA has the function of conducting the safety regulation of a range of matters, including, under paragraph 9(1)(c), developing and promulgating appropriate, clear and concise aviation safety standards.

Section 98 of the Act empowers the Governor-General to make regulations for the Act and in the interests of the safety of air navigation. Relevantly, the Governor-General has made the Civil Aviation Safety Regulations 1998 (CASR). Under subsection 98(5A) of the Act, the regulations may empower CASA to issue instruments in relation to, among other matters, matters affecting the safe navigation and operation, or the maintenance, of aircraft.

Part 91 Manual of Standards

For subsection 98(5A) of the Act, regulation 91.040 of CASR empowers CASA to issue a Manual of Standards for Part 91 of CASR that prescribes matters required or permitted by the regulations to be prescribed, or necessary or convenient for carrying out or giving effect to Part 91. The power in regulation 91.040 is complemented by other provisions throughout Part 91 which empower CASA to prescribe specific matters in the Part 91 MOS. The Part 91 MOS is also made under regulation 201.025 of CASR, which empowers CASA to issue instruments prescribing matters for definitions in these Regulations relating to matters mentioned in the subsection.

Part 91 of CASR sets out the general operating and flight rules for Australian aircraft, and specified foreign registered aircraft operating in Australian territory.

Under subregulation 91.810(1) of CASR, the Part 91 MOS may prescribe requirements relating to:

(a) the fitment and non-fitment of equipment to an aircraft; and

(b) the carrying of equipment on an aircraft; and

(c) equipment that is fitted to, or carried on, an aircraft.

Under subregulation 91.810(2), a person contravenes the subregulation if the person is subject to a requirement mentioned in subregulation 91.810(1) and the requirement is not met.

Under subregulation 91.810(3), a person commits an offence of strict liability (with a maximum penalty of 50 penalty units) if the person contravenes subregulation 91.810(2).

Subregulation 91.020 of CASR provides that Part 91 does not apply in relation to:

(a) a foreign registered aircraft that is operated in Australian territory under a foreign air transport Air Operator’s Certificate (AOC); or

(b) a foreign registered aircraft that is operated in Australian territory under a New Zealand AOC with ANZA privileges that is in force for Australia.

Part 121 Manual of Standards

For subsection 98(5A) of the Act, regulation 121.015 of CASR empowers CASA to issue a Manual of Standards for Part 121 of CASR that prescribes matters required or permitted by the regulations to be prescribed, or necessary or convenient for carrying out or giving effect to Part 121 (the Part 121 MOS). Part 121 of CASR prescribes requirements for the conduct of Australian air transport operations in larger aeroplanes (the aeroplanes described in regulation 121.005 of CASR).

The power in regulation 121.015 is complemented by other provisions, throughout Part 121 of CASR, which empower CASA to prescribe specific matters in the Part 121 MOS.

Under subregulation 121.460(1) of CASR, the Part 121 MOS may prescribe requirements relating to:

(a) the fitment and non-fitment of equipment to an aeroplane; and

(b) the carrying of equipment on an aeroplane; and

(c) equipment that is fitted to, or carried on, an aeroplane.

Under subregulation 121.460(2), a person contravenes the subregulation if the person is subject to a requirement mentioned in subregulation 121.460(1) and the requirement is not met.

Under subregulation 121.460(3), a person commits an offence of strict liability (with a maximum penalty of 50 penalty units) if the person contravenes subregulation 121.460(2).

Part 133 Manual of Standards

For subsection 98(5A) of the Act, regulation 133.020 of CASR empowers CASA to issue a Manual of Standards for Part 133 of CASR that prescribes matters required or permitted by the regulations to be prescribed, or necessary or convenient for carrying out or giving effect to Part 133 (the Part 133 MOS). Part 133 of CASR prescribes requirements for the conduct of Australian air transport operations in rotorcraft. Air transport operations include passenger transport operations, cargo transport operations and medical transport operations that are conducted for hire or reward.

The power in regulation 133.020 is complemented by other provisions, throughout Part 133 of CASR, which empower CASA to prescribe specific matters in the Part 133 MOS.

Under subregulation 133.360(1) of CASR, the Part 133 MOS may prescribe requirements relating to:

(a) the fitment and non-fitment of equipment to a rotorcraft; and

(b) the carrying of equipment on a rotorcraft; and

(c) equipment that is fitted to, or carried on, a rotorcraft.

Under subregulation 133.360(2), a person contravenes the subregulation if the person is subject to a requirement mentioned in subregulation 133.360(1) and the requirement is not met.

Under subregulation 133.360(3), a person commits an offence of strict liability (with a maximum penalty of 50 penalty units) if the person contravenes subregulation 133.360(2).

Part 135 Manual of Standards

For subsection 98(5A) of the Act, regulation 135.025 of CASR empowers CASA to issue a Manual of Standards for Part 135 of CASR that prescribes matters required or permitted by the regulations to be prescribed, or necessary or convenient for carrying out or giving effect to Part 135 (the Part 135 MOS). Part 135 of CASR prescribes requirements for the conduct of Australian air transport operations in smaller aeroplanes (aeroplanes that have a maximum operational passenger seating configuration of not more than 9 and a maximum take-off weight of not more than 8 618 kg).

The power in regulation 135.025 is complemented by other provisions, throughout Part 135 of CASR, which empower CASA to prescribe specific matters in the Part 135 MOS.

Under subregulation 135.370(1) of CASR, the Part 135 MOS may prescribe requirements relating to:

(a) the fitment and non-fitment of equipment to an aeroplane; and

(b) the carrying of equipment on an aeroplane; and

(c) equipment that is fitted to, or carried on, an aeroplane.

Under subregulation 135.370(2), a person contravenes the subregulation if the person is subject to a requirement mentioned in subregulation 135.370(1) and the requirement is not met.

Under subregulation 135.370(3), a person commits an offence of strict liability (with a maximum penalty of 50 penalty units) if the person contravenes subregulation 135.370(2).

Other legislation

Under subsection 33(3) of the Acts Interpretation Act 1901, where an Act confers a power to make, grant or issue any instrument of a legislative or administrative character (including rules, regulations or by-laws), the power shall be construed as including a power exercisable in the like manner and subject to the like conditions (if any) to repeal, rescind, revoke, amend, or vary any such instrument. Under subsection 13(1) of the Legislation Act 2003 (the LA), subsection 33(3) applies to legislative instruments as if each provision of the instrument were a section of an Act.

Under subsection 14(1) of the LA , a legislative instrument may make provision in relation to matters by applying, adopting or incorporating provisions of an Act or disallowable legislative instrument as in force at a particular time or as in force from time to time. A legislative instrument may also make provision in relation to matters by applying, adopting or incorporating any matter contained in any other instrument or writing as in force at, or before, the time the legislative instrument commences. Under subsection 14(2), unless the contrary intention appears, the legislative instrument may not make provision in relation to a matter by applying, adopting or incorporating any matter contained in an instrument or other writing as in force or existing from time to time. However, subsection 98(5D) of the Act provides that, despite section 14 of the LA, a legislative instrument made under the Act or the regulations may apply, adopt or incorporate any matter contained in any instrument or other writing as in force or existing from time to time, even if the other instrument or writing does not yet exist when the legislative instrument is made.

Background

Radio altimeters perform a critical function during instrument approach operations and need to operate reliably. They are the only instruments on board an aircraft that accurately measure its height above the underlying terrain and obstacles, providing data required for the aircraft’s safety to the flight crew and other aircraft systems.

As mentioned above, radio altimeters operate in the 4.2 – 4.4 GHz radio frequency band and the most recent of the 5G transmission systems in Australia are licensed to operate in a nearby band (i.e. 3.7 – 4.0 GHz). Studies have shown that 5G transmissions in this band can interfere with the operation of radio altimeters. The interference can result in intermittent operation, false data and indications, or system failure.

The situation is most critical for aircraft conducting instrument approach procedures under low-visibility conditions. The risks of radio altimeters being impaired during these operations include nuisance alerts and/or a failure to alert, increased flight crew workload, aborted landings (go-arounds) and, in the worst case, accidents.

The instrument approach operations determined to be reliant on radio altimeters are:

• Instrument Landing System Category II and III (ILS Cat II and III)
• Special Authorisation Category I and II (SA Cat I and II).

These operations are known as low-visibility approaches.

When ACMA granted new licences in the 3.7 – 4.0 GHz band to 5G wireless broadband system operators, it imposed conditions to mitigate the effects of 5G transmissions on radio altimeters. However, these measures are scheduled to end on 31 March 2026.

The protective measures imposed by ACMA consisted of:

• exclusion zones surrounding runways where mobile communication stations are not allowed to be installed
• restricted zones, covering the final approach path from a height of 2 000 ft, where the signals from mobile communication transmitters need to be below power levels shown to affect the operation of radio altimeters.

As at the commencement of the instrument, further information regarding the protective measures imposed by ACMA is available on the ACMA website.

Radio altimeters need to operate reliably in the presence of 5G transmissions, both before and after these protective measures are removed. To this end, CASA issued media statements in October 2024 advising aircraft operators of the need to ensure radio altimeters comply with FAA ADs prior to the protective measures being withdrawn. Then in 2025 CASA published, for consultation, a draft of the instrument adopting the FAA ADs under the relevant MOSs.

There is currently no recognised international standard for radio altimeters which will enable them to operate without any protection from 5G wireless broadband stations. The FAA AD performance requirements represent the most protective internationally-recognised technical standard currently available.

The new requirements apply to aircraft (aeroplanes and rotorcraft) that use low-visibility approaches. The changes to the relevant MOSs will ensure that operators of such aircraft comply with the FAA radio altimeter performance requirements applicable for their aircraft that are set out in:

• FAA Airworthiness Directive AD 2023-10-12 (FAA AD 2023-10-02) — for aeroplanes
• FAA Airworthiness Directive AD 2023-11-07 (FAA AD 2023-11-07) — for rotorcraft.

CASA 06/26 — Foreign Registered Aircraft in Australian Territory (Radio Altimeters) Direction 2026 (CASA 06/26) will commence on 1 April 2026 and impose the same obligations on operators of the following aircraft:

• foreign registered aircraft operating in Australian territory under a foreign air transport AOC
• foreign registered aircraft operating in Australian territory under a New Zealand AOC with ANZA privileges that is in force for Australia.

However, under CASA 06/26 operators will be excluded from these obligations if the aircraft are used for the conduct low-visibility approaches at aerodromes included in a written list maintained by CASA. CASA intends to only list aerodromes at which a 5G wireless broadband station has not started to operate. This arrangement will be in place until the end of 31 March 2027. A more detailed explanation of CASA 06/26 is set out in the Explanatory Statement for that instrument.

Under CASA EX15/26 — Aircraft Used for Low-visibility Approaches (Radio Altimeters) Exemption 2026 (CASA EX15/26), a short-term exemption based on a similar arrangement will be granted to aircraft operators and pilots in command of aircraft used for low-visibility approaches from the requirements for radio altimeters imposed by this instrument. A more detailed explanation of CASA EX15/26 is set out in the Explanatory Statement for that instrument.

The requirements imposed by the instrument are expected to be reviewed once new global standards for radio altimeters are finalised. The new international standards are expected to be promulgated in 2027. CASA anticipates that the requirements imposed by the instrument will remain in force until such time as equipment compliant with the new standards become readily available. It is expected that radio altimeters built to the new international standards will be more resilient to external radio frequency emissions than currently available models.

In the interim, CASA is encouraging aircraft operators purchasing new aircraft or replacing radio altimeters to opt for units which offer the highest protections against radio frequency interference, and to keep reporting to CASA incidents of suspected interference to radio altimeters caused by 5G wireless broadband stations.

Overview of instrument

In accordance with subsection 33(3) of the Acts Interpretation Act 1901, the instrument amends the relevant MOSs to impose requirements on the operator (or, in the case of the amendment to the Part 91 MOS, the pilot in command) of an aircraft used for the conduct of low-visibility approaches in relation to radio altimeters. The person on whom the obligation is imposed must ensure that each radio altimeter installed on such an aircraft complies with the requirements for radio frequency interference tolerance specified in either FAA AD 2023‑10-02 for a “radio altimeter tolerant airplane” or FAA AD 2023-11-07 for a “radio altimeter tolerant rotorcraft”, depending upon the kind of aircraft to which the MOS applies, as follows:

• for aeroplanes — Part 91 MOS, Part 121 MOS and Part 135 MOS –
  FAA AD 2023-10-02 as existing on 26 May 2023
• for rotorcraft — Part 91 MOS and Part 133 MOS – FAA AD 2023-11-07 as existing on 22 June 2023.

The new requirements will commence on 1 April 2026.

Low-visibility approach is defined in Part 1 of the CASR Dictionary as meaning an approach using minima for a runway that are below the category I precision approach minima for the runway published in the AIP. Low-visibility approaches are the following instrument approach procedures (IAPs):

• Instrument Landing System Category II and III (ILS Cat II and III)
• Special Authorisation Category I and II (SA Cat I and II).

The FAA AD performance requirements for radio altimeters do not apply in relation to radio altimeters fitted to aircraft used for the conduct of Required Navigation Performance – Approval Required (RNP-AR) IAPs (see under the heading Consultation below).

CASA has assessed the impact of the instrument on aviation safety and considers that the proposed amendments are necessary to maintain safety during a critical phase of an aircraft’s approach and landing at aerodromes at which 5G stations are operating.

Documents incorporated by reference

Subsection 98(5D) of the Act provides that, despite section 14 of the LA, a legislative instrument made under the Act or the regulations may apply, adopt or incorporate any matter contained in any instrument or other writing as in force or existing from time to time, even if the other instrument or writing does not yet exist when the legislative instrument is made.

In accordance with paragraph 15J(2)(c) of the LA, the following table contains a description of the documents incorporated by reference into the relevant MOSs, the organisation responsible for each document and how they may be obtained. The table also states how the document is incorporated.

Content of instrument

Section 1 names the instrument.

Section 2 provides that the instrument commences on the day after it is registered.

Section 3 provides that each Manual of Standards mentioned in the title of a Schedule to the instrument is amended in accordance with the Schedule.

Schedule 1 amends the Part 91 MOS (the Part 91 (General Operating and Flight Rules) Manual of Standards 2020).

Item 1 of Schedule 1 inserts a new section 26.26A into the Part 91 MOS.

Subsection 26.26A(1) states that the section applies from the beginning of 1 April 2026.

Subsection (2) states that each radio altimeter fitted to an aeroplane used for the conduct of a low-visibility approach in Australian territory must comply with the requirements for tolerance to radio frequency interference specified for a “radio altimeter tolerant airplane” in FAA AD 2023-10-02 as existing on 26 May 2023.

A note is included under this subsection that explains the meaning of “radio altimeter tolerant airplane” under FAA AD 2023-10-02. A second note explains that 26 May 2023 is the date that AD was published in the Federal Register of the United States Government.

Subsection (3) states that each radio altimeter fitted to a rotorcraft used for the conduct of a low-visibility approach in Australian territory must comply with the requirements for tolerance to radio frequency interference specified for a “radio altimeter tolerant rotorcraft” in FAA AD 2023-11-07 as existing on 22 June 2023.

A note is included under this subsection that explains the meaning of “radio altimeter tolerant rotorcraft” under FAA AD 2023-11-07. A second note explains that 22 June 2023 is the date that AD was published in the Federal Register of the United States Government.

Because of subsection 26.01(2) of the Part 91 MOS, the pilot in command is subject to these requirements relating to radio altimeters.

Schedule 2 amends the Part 121 MOS (the Part 121 (Australian Air Transport Operations—Larger Aeroplanes) Manual of Standards 2020).

Item 1 of Schedule 2 inserts a new section 11.20A into the Part 121 MOS.

Section 11.20A states that from the beginning of 1 April 2026, each radio altimeter fitted to an aeroplane used for the conduct of a low-visibility approach in Australian territory must comply with the requirements for tolerance to radio frequency interference specified for a “radio altimeter tolerant airplane” in FAA AD 2023-10-02 as existing on 26 May 2023.

A note is included under this section that explains the meaning of “radio altimeter tolerant airplane” under FAA AD 2023-10-02. A second note explains that 26 May 2023 is the date that AD was published in the Federal Register of the United States Government.

Because of subsection 11.03(1) of the Part 121 MOS, the operator of the aeroplane must ensure that these requirements relating to radio altimeters are met.

Schedule 3 amends the Part 133 MOS (the Part 133 (Australian Air Transport Operations—Rotorcraft) Manual of Standards 2020).

Item 1 of Schedule 3 inserts a new section 11.17A into the Part 133 MOS.

Section 11.17A states that from the beginning of 1 April 2026, each radio altimeter fitted to a rotorcraft used for the conduct of a low-visibility approach in Australian territory must comply with the requirements for tolerance to radio frequency interference specified for a “radio altimeter tolerant rotorcraft” in FAA AD 2023-11-07 as existing on 22 June 2023.

A note is included under this section that explains the meaning of “radio altimeter tolerant rotorcraft” under FAA AD 2023-11-07. A second note explains that 22 June 2023 is the date that AD was published in the Federal Register of the United States Government.

Because of subsection 11.01(2) of the Part 133 MOS, these requirements relating to radio altimeters apply to the rotorcraft’s operator.

Schedule 4 amends the Part 135 MOS (the Part 135 (Australian Air Transport Operations—Smaller Aeroplanes) Manual of Standards 2020).

Item 1 of Schedule 4 inserts a new section 11.21A into the Part 135 MOS.

Section 11.21A states that from the beginning of 1 April 2026, each radio altimeter fitted to an aeroplane used for the conduct of a low-visibility approach in Australian territory must comply with the requirements for tolerance to radio frequency interference specified for a “radio altimeter tolerant airplane” in FAA AD 2023-10-02 as existing on 26 May 2023.

A note is included under this section that explains what a “radio altimeter tolerant airplane” is under FAA AD 2023-10-02. A second note explains that 26 May 2023 is the date that AD was published in the Federal Register of the United States Government.

Because of subsection 11.01(2) of the Part 135 MOS, these requirements relating to radio altimeters apply to the aeroplane’s operator.

Legislation Act 2003

Under subsection 8(4) of the LA, an instrument is a legislative instrument if it is made under a power delegated by the Parliament, any provision of it determines the law or alters the content of the law, and it has the direct or indirect effect of affecting a privilege or interest, imposing an obligation, creating a right, or varying or removing an obligation or right. The instrument satisfies these requirements.

Paragraph 10(1)(d) of the LA provides that an instrument will be a legislative instrument if it includes a provision that amends or repeals another legislative instrument. This instrument amends the relevant MOSs, which are legislative instruments. The instrument is, therefore, also a legislative instrument and subject to tabling and disallowance in the Parliament under sections 38 and 42 of the LA.

Sunsetting

Part 4 of Chapter 3 of the LA (the sunsetting provisions) does not apply to the instrument, because the instrument relates to aviation safety and is made under CASR (item 15 of the table in section 12 of the Legislation (Exemptions and Other Matters) Regulation 2015).

The instrument deals with aviation safety matters that, once identified, require a risk response or treatment plan. Generally speaking, item 15, when invoked, is necessary to ensure that, in the interests of aviation safety, a relevant instrument has enduring effect, certainty and clarity for aviation operators and organisations. That is the case for the Manuals of Standards themselves, which are enduring pieces of aviation safety legislation.

However, the instrument is an amending instrument and, therefore, will be automatically repealed under section 48A of the LA, which will happen before the sunsetting provisions would have repealed the instrument if they had applied.

Consultation

Consultation under section 17 of the LA was undertaken on a draft of the instrument before the instrument was made. The consultation opened on 7 July 2025 and closed on 3 August 2025 and was undertaken at the same time as consultation on instrument CASA 06/26, the related direction for foreign registered aircraft.

Fourteen responses were received. Of the 14 responses received:

• 9 responses were sent on behalf of airlines
• 4 responses were received from individuals
• 1 was from an aircraft manufacturer.

As a result of the consultation feedback, and further risk analysis of the safety impact of 5G transmissions on the conduct of RNP-AR IAPs, CASA removed the requirement in the draft instrument for operators of aircraft fitted with radio altimeters that are used for RNP-AR IAPs from having to ensure that the radio altimeters comply with the FAA performance requirements. This is consistent with the approach taken by the FAA, which revised its ADs to remove RNP-ARs from the list of operations considered susceptible to 5G transmissions.

CASA is satisfied that no further consultation is appropriate or reasonably practicable for this instrument for section 17 of the LA.

Sector risk, economic and cost impact

Subsection 9A(1) of the Act states that, in exercising its powers and performing its functions, CASA must regard the safety of air navigation as the most important consideration. Subsection 9A(3) of the Act states that, subject to subsection (1), in developing and promulgating aviation safety standards under paragraph 9(1)(c), CASA must:

(a) consider the economic and cost impact on individuals, businesses and the community of the standards; and

(b) take into account the differing risks associated with different industry sectors.

The cost impact of a standard refers to the direct cost (in the sense of price or expense) which a standard would cause individuals, businesses and the community to incur. The economic impact of a standard refers to the impact a standard would have on the production, distribution and use of wealth across the economy, at the level of the individual, relevant businesses in the aviation sector, and the community more broadly. The economic impact of a standard could also include the general financial impact of that standard on different industry sectors.

The economic and cost impact of the instrument has been determined by:

(a) the identification of individuals and businesses affected by the instrument; and

(b) consideration of how the requirements to be imposed on individuals and businesses under the instrument will be different compared to existing requirements; and

(c) a valuation of the impact, in terms of direct costs, on individuals and businesses affected by the instrument to comply with the different requirements. This valuation is consistent with the principles of best practice regulation of the Australian Government; and

(d) a valuation of the impact the different requirements would have on the production, distribution and use of wealth across the economy, at the level of the individual, relevant businesses in the aviation sector and the community more broadly; and

(e) consideration of community impacts, beyond those direct impacts on individuals and businesses affected by the instrument, that are relevant if the instrument were to result in flow‑on effects to other aviation businesses, or local non-aviation businesses that experience a change in their activity due to the instrument.

The amendments are required because the most recent 5G systems in Australia are licensed to operate in a frequency band near to the radio altimeter frequency band and can interfere with radio altimeters. This is an issue faced by other National Aviation Authorities and the approach taken in the instrument is consistent with the approach taken by the FAA.

Under the amendments, radio altimeter upgrades are only required for radio altimeters fitted to aircraft conducting low-visibility approaches (only available at Melbourne, Sydney, Canberra and Perth airports (and at Western Sydney International when it begins operations)). Aircraft operators can choose to avoid the direct costs of upgrading by not conducting low-visibility approaches. However, this may incur indirect costs such as increased fuel carriage or diversions to airports other than the desired destination.

Most of the amendments made by the instrument to Manuals of Standards must be complied with by operators of aircraft (other than the amendment made to the Part 91 MOS which applies to pilots in command). Currently there are 18 operators approved by CASA to undertake low-visibility operations. It was determined during informal and formal consultation that most of these operators are upgrading or replacing radio altimeters to meet the FAA AD requirement. Many radio altimeters fitted to aircraft already meet the FAA AD requirements, as this is a requirement for air transport aircraft that fly to the United States of America. New aircraft are likely to be supplied with radio altimeters that are compliant with the relevant FAA AD.

As of February 2026, CASA estimates that there are approximately 90 aircraft that will need upgraded radio altimeters in order to undertake low-visibility operations from 1 April 2026. The average cost to ensure compliance with the FAA AD requirement is estimated at $70 000.

However, the immediate impact of these amendments is ameliorated by CASA EX15/26, which provides affected operators with a further period of up to 12 months after 1 April 2026 in which to complete the necessary equipment upgrades. That period will be shortened in relation to a particular airport if a 5G mobile base station becomes active in the extended runway centreline zone at the airport before the end of the 12 months. Access to that exemption is anticipated to allow operators to manage cost, supply or maintenance scheduling challenges which would have prevented them from completing upgrades before 1 April 2026.

Impact on categories of operations

The operators of aircraft to which the instrument applies may be unable to use some of their aircraft for low-visibility approaches at those airports that have facilities for low-visibility instrument approaches (Sydney, Melbourne, Perth, Canberra and Western Sydney International Airport when it opens in 2026) if the radio altimeters of those aircraft do not comply with the new requirements, unless CASA provides alleviation from the requirements. However, operators have been advised of the new requirements in advance, and many operators have other aircraft with compliant radio altimeters that can perform these approaches.

Impact on regional and remote communities

The instrument will have no specific impact on regional and remote communities.

Office of Impact Analysis (OIA)

An impact analysis (IA) is not required in this case, as the instrument is covered by a standing agreement between CASA and the OIA under which an IA is not required for amendments to Manuals of Standards (OIA reference number OIA23-06250).

Statement of Compatibility with Human Rights

The Statement of Compatibility with Human Rights at Attachment 1 has been prepared in accordance with Part 3 of the Human Rights (Parliamentary Scrutiny) Act 2011.

Making and commencement

The instrument has been made by the Director of Aviation Safety, on behalf of CASA, in accordance with subsection 73(2) of the Act.

The instrument commences on the day after it is registered and is automatically repealed in accordance with section 48A of the LA.

Attachment 1

Statement of Compatibility with Human Rights

Prepared in accordance with Part 3 of the
Human Rights (Parliamentary Scrutiny) Act 2011

Parts 91, 121, 133 and 135 Manuals of Standards Amendment Instrument 2026

This legislative instrument is compatible with the human rights and freedoms
recognised or declared in the international instruments listed in section 3 of the
Human Rights (Parliamentary Scrutiny) Act 2011.

Overview of the legislative instrument

The purpose of the legislative instrument is to amend 4 Manuals of Standards to ensure each radio altimeter fitted to aircraft operates reliably in the presence of fifth-generation (5G) wireless broadband transmissions when the aircraft is used for the conduct of low-visibility approaches in Australian territory.

The instrument amends specified Manuals of Standards to require aircraft operators ensure that each radio altimeter fitted to an aeroplane or rotorcraft used for low-visibility approaches at Australian aerodromes meets the requirements for tolerance to radio frequency interference set out in a specified Federal Aviation Administration of the United States of America (FAA) Airworthiness Directive (AD) that applies for the kind of aircraft. The requirement imposed by the amendment to the Part 91 Manual of Standards is imposed on the pilot in command.

The specified FAA ADs are:

• AD 2023-10-12 — for aeroplanes
• AD 2023-11-07 — for rotorcraft.

The requirements imposed by the amendments will commence on 1 April 2026. This is because interim measures imposed by the Australian Communications and Media Authority to mitigate the effects of 5G transmissions on radio altimeters around airports are scheduled to end on 31 March 2026. The requirements are expected to be reviewed once new global standards for radio altimeters are developed.

Human rights implications

The instrument promotes the right to life in Article 6 of the International Covenant on Civil and Political Rights by protecting aviation safety during the conduct of low-visibility approaches for landing of aircraft.

Conclusion

This legislative instrument is compatible with human rights.

Civil Aviation Safety Authority