We are working with the aviation industry and the Australian Communications and Media Authority (ACMA) to ensure the safety of flights during the introduction of the expanded 5th generation (5G) mobile network in Australia.
This includes measures to mitigate potential interference from 5G to radio altimeters (radalts).
Background
Pilots use radalts to determine an aircraft’s height above terrain. Other safety systems on aircraft also use radalts making them important to some aircraft operations including final approach and landing, especially when visibility is poor and the flight crew are reliant on the aircraft’s instruments
5G is expanding worldwide, bringing faster network speeds and reduced latency. 5G will also support new applications and technologies across Australia.
In Australia, 4G and 5G wireless broadband services have been operating in the nearby 3.4-3.7GHz band since 2016 and 2019 respectively. Radalts operate in the radio frequency band between 4.2 and 4.4 GHz. ACMA is planning new allocations for 5G in the adjacent 3.7-4.0 GHz spectrum.
There has been international concern about the interaction between 5G and radalts. Concerns include the potential for interference to radalts resulting in intermittent operation, false measurements, or temporary loss of function.
Potential issues and reporting
If aircraft operators experience issues where newly deployed 5G wireless communications operate near aircraft and airports, we encourage them to continue reporting this through our defect report service.
We would like occurrences at or below 2500ft AGL of:
- all spurious radalt displays or indications during take-off and landing
- any aircraft system faults/failures caused by radalt RA inputs/data.
Refer to Airworthiness Bulletin AWB 34-020 for further details on what to report.
Upgrading radalts
In the United States, the FAA has mandated that aircraft operators upgrade to the highest performing radalts currently available (those which meet what is known as the Group 4 performance standard) to operate without operational restrictions.
Separately, the Radio Technical Commission for Aeronautics (RTCA) and the European Organisation for Civil Aviation Equipment (EUROCAE) are currently updating the international standards for radio altimeters. These updates will ensure they can operate reliably when near 5G signals.
We will provide further information on available avenues for operators to upgrade their radalts.
Mitigations until 31 March 2026
ACMA has introduced measures to protect radio altimeters from 5G transmissions until 31 March 2026.
The mitigations restrict wireless broadband deployments in the 3.7-4.0 GHz band around runways and approaches at 19 airports across Australia nominated by CASA. These are airports with instrument approach procedures which are reliant on radio altimeters:
- Avalon (Vic)
- Adelaide (SA)
- Alice Springs (NT)
- Ballina (NSW)
- Brisbane (Qld)
- Broome (WA)
- Cairns (Qld)
- Canberra (ACT)
- Darwin (NT)
- Gold Coast (Qld)
- Hamilton Island (Qld)
- Melbourne (Vic)
- Mount Isa (Qld)
- Norfolk Island
- Perth (WA)
- Sunshine Coast (Qld)
- Sydney (NSW)
- Townsville (Qld)
- Wellcamp (Qld)
The mitigation measures also restrict the 5G signal power which aircraft on final approach and landing will be exposed to.
We do not expect to impose operational restrictions on air operators during this interim period, however we will keep monitoring the situation and will review any incident reports we receive.
Operating internationally
United States
In the United States (US), the Federal Aviation Administration (FAA) has published airworthiness directives for 5G. These directives require specified categories of aircraft to be fitted with radio altimeters which meet minimum performance standards.
We have issued exemptions to these directives in EX81/23, because of the mitigation measures being implemented. However, Australian aircraft operators that fly into the United States will have to comply with the FAA rules. This includes upgrading equipment where required.
Other countries
Australian aircraft operators that fly to other countries will need to comply with the rules regarding radio altimeters imposed by the relevant aviation authorities in those countries.