As the 5G mobile network expands, it could interfere with radio altimeters (radalts).
The Australian Communications and Media Authority (ACMA) has put temporary measures in place to reduce the effect of 5G transmissions around airports. These measures end on 31 March 2026. An exemption applies if 5G towers are not installed yet.
Read more about 5G and aviation safety.
What operators must do
Operators conducting low-visibility approaches must upgrade their radalts.
Low-visibility approaches include:
- Instrument Landing System (ILS) category II and III
- Special Authorisation ILS category I and II.
When you must upgrade your radalts
You must upgrade your radalt when a 5G base station begins operating in a runway notification zone at that aerodrome.
If a base station hasn't been installed yet, you can use exemption (CASA EX15/26) until a station is installed.
We strongly encourage operators to continue upgrading their radar altimeter during the period of exemption.
We will notify operators and update this page regarding any changes with a maximum of 4 weeks' notice.
We will not provide individual exemptions to operators who have not upgraded their radio altimeter when a 5G station becomes active near an aerodrome.
Radalt requirements
We have adopted the performance requirements from the following United States' Federal Aviation Administration (FAA) airworthiness directives. These provide the most protective internationally recognised technical standard available:
- AD 2023-10-02 (aeroplanes)
- AD 2023-11-07 (rotorcraft).
Operators should talk to aircraft and equipment manufacturers about upgrading or replacing radalt equipment.
Legislation changes from 31 March 2026
From 31 March 2026, new radalt requirements apply to domestic and foreign aircraft operators conducting instrument approach procedures with minima below ILS Category I.
Part 129 operators and NZ AOC with ANZA privilege
The requirements are in:
- CASA 06/26 Foreign registered aircraft in Australian territory (radio altimeters) direction (we will include the the link when it's published on the Federal Register of Legislation website)
This instrument applies to:
- foreign air transport air operator certificate (AOC) holders operating under CASR Part 129
- New Zealand AOC holders with Australia New Zealand (ANZA) privileges.
The direction provides operators extra time to upgrade their radalts after 31 March 2026.
Domestic operators and other foreign operators
Requirements for domestic operators and other foreign operators are contained in our amended Manuals of Standards:
- Part 91 MOS – Section 26.26A – for all domestic operators other than Australian air transport operators, and all other foreign operators
- Part 121 MOS – Section 11.20A – for larger aeroplane Australian air transport operators
- Part 133MOS – Section 11.17A – for rotorcraft Australian air transport operators
- Part 135 MOS – Section 11.21A – for smaller aeroplane Australian air transport operators.
The temporary exemption CASA EX15/26 provides domestic operators and other foreign operators additional time to upgrade after 31 March 2026:
- CASA EX15/26 – Aircraft Used for Low-visibility Approaches (Radio Altimeters) Exemption 2026
RNP-AR approaches do not require radalt upgrades
In December 2025 we removed Required Navigation Performance – Authorisation Required (RNP-AR) instrument approach procedures from the requirement to upgrade radalt.
We did this because:
- Design rules for RNP-AR approaches don't rely on radalt to show height. They use barometric altitude instead.
- Incorrect radalt data may affect the aircraft's allowed maximum bank angle. If the aircraft cannot stay on the RNP-AR path, the pilot will get an 'unable RNP' alert and must stop the approach.
- Aircraft using RNP-AR must also have terrain awareness and warning systems (TAWS).Some TAWS use radaltdata. A false TAWS alert could distract the pilot. If the aircraft cannot follow the path, the automation will still tell the pilot to stop the approach. 
Other operations this may affect
We will continue to review other operations which require the use of radalts, such as NVIS helicopter operations.
We will engage with the industry before making any further changes.
Aerodromes with low-visibility procedures
As of March 2026, 5 aerodromes have low-visibility instrument approach procedures: 
- Canberra
- Melbourne
- Perth
- Sydney
- Western Sydney (forthcoming).
None of these have 5G base stations in the runway notification zone.
Reporting issues
Use our defect report service to report aircraft issues that 5G wireless communications may have caused.
Please report:
- occurrences at or below 2500 ft above ground level
- all incorrect radalt displays or indications during take-off and landing
- any aircraft system faults or failures caused by radalt inputs or data.
Refer to Airworthiness Bulletin AWB 34-020 for further details on what to report:
Operating overseas
United States
Australian aircraft operators that fly into the United States must follow the FAA rules. This may include upgrading equipment in line with the airworthiness directives for radalts.
Other countries
Australian aircraft operators flying to other countries must follow the rules set by the local aviation authorities. These rules may differ from Australian regulations.