Airport operators across Australia warn 5G services in certain spectrum bands could interfere with radio altimeters in aircraft.

Australian aircraft flying in controlled airspace are so far protected from the effects of 5G signals on their safety systems and there is no indication of any problems in the US.

The Civil Aviation Safety Authority of Australia (CASA), has been closely following the issue, and has not seen any evidence that 5G transmissions are currently affecting planes.

Airport operators across Australia warned that 5G services within certain spectrum bands could cause interference with radio altimeters on planes, which could pose a threat to passenger safety by impacting aircraft systems like automatic landings, wind prediction, and terrain warnings.

The Australian Communications and Media Authority (ACMA) received comments and is currently consulting on the replanning or reuse of the 3.4GHz spectrum that was once with NBN Co and the 3.7GHz-4.2GHz spectrum in order to, among other things, support 5G services..

CASA stated that there have been no reports from the Australian Transport Safety Bureau of radio altimeter incidents related to 5G since the introduction of telecommunications technology 2 years ago.

It issued a airworthiness bulletin on the 5G issue on 24 December 2021 to alert pilots and airlines of possible interference.

CASA also cautioned the Australian Communications and Media Authority, who manages the assignment of frequency spectrum in Australia.

One of the main differences between Australia’s 5G network and the US’s is that transmissions do not reach the part of spectrum that CASA fears for the US aviation industry.

The frequency range of aircraft radio altimeters is 4.2-4.4Ghz, and 5G transmissions that are subject to interference debate are within the adjacent spectrum of 3.7-4.2GHz. Australian 5G transmissions peak at 3.7GHz according to CASA, which is well below radio altimeter frequencies.

Airservices Australia stated that aircraft radio altimeters are “highly vulnerable to RF interference entering their receivers, which could negatively impact their performance.”

It also wrote “A set of worst-case circumstances leading to an aircraft accident could conceivably exist in the real world due to the uncontrolled nature of aircraft refection near 5G base stations.”

The Australian Airports Association, representing over 330 airports and aerodromes in Australia, supports mitigations to “limit any potential adverse impacts on aviation caused by the proposed re-allocations of the 5G spectrum”.

Boeing Australia says that mitigations varied from country to country, and that “one size does not fit all” when it came to shielding aviation systems from potential interference.

A CASA spokesman said in January “we are monitoring the situation but telecommunications companies in Australia do not operate 5G in a higher frequency range used in the US and believed to affect radio altimeters.”

“We are not aware of any confirmed cases of 5G interference with radio altimeters in this country since the technology rolled out. Nonetheless, we have asked pilots to report radio altimeter issues so that any information on potential interference can inform future decisions.” says the CASA spokesman.

Sydney Airport (YSSY) also raised other “potential” impacts from 5G in a submission of its own.

“Increased 5G around airports could lead to more flight diversions in low visibility conditions like heavy fog, increase the landing distance requirements for aircraft flying in wet weather and make shorter runways usable,” says Sydney Airport

The ACMA proposed a re-allocation which would allow telecommunication companies licenses to utilize frequencies adjacent to the RA band for Wireless Broadband (WBB) 5G operations.

CASA says that it “understands ACMA will protect aviation from interference from other transmissions” in keeping with obligations under the Radiocommunications Act.

In 2021, US airlines and aircraft producers raised serious concerns about the proximity to a segment of airwaves used by American telecommunications companies for 5G were to close to those used by radio altimeters to measure aircraft clearance over terrain.

There’s good news for high flyers who are worried about the fierce debate in the United States about the impact of 5G signals on aircraft safety systems: there are no indications of similar problems in Australia.

Qantas also insisted it is perfectly safe to fly its Boeing A380s and 787s to the US, despite numerous airlines cancelling US flights or changing flightpaths in the midst of concerns.

Chief technical pilot, Captain Alex Passerini says Qantas flights in the United States will fully comply with the safety regulator’s requirements.

“We would never operate unless it was completely safe to do so.” says Pesserini