Why new 5G tech could pose big risk to airline safety

US carriers are concerned that newly auctioned 3.7-3.98 GHz spectrum may interfere with key aviation instruments such as altimeters

The FAA has introduced a set of 5G directives that bar the use of radio altimeters at around 40 US airports. (Representational image)

In a development that most fliers would find worrying, the top executives of American passenger and cargo airlines have said the 5G service set for launch in the US may leave a large number of aircraft unusable. This could cause chaos for US flights, and disrupts journeys, they said. The 5G services are being rolled out by AT&T and Verizon.

US aviation regulator Federal Aviation Administration (FAA) has also warned that the new 5G technology may interfere with altimeters and other flight instruments, said a Reuters report. Altimeters, which measure the height of the plane from the ground, typically operate in the 4.2-4.4 GHz range. This may be too close to the 3.7-3.98 GHz range that the US auctioned to mobile phone companies in early 2021. The US government had auctioned the spectrum, called the C band, for $80 billion.

Altimeters go beyond reading the height. They facilitate automated landings and help detect wind shear.

Possible disruptions


The FAA has put forth a set of 5G directives that bar the use of radio altimeters at around 40 airports. These include some of the busiest airports in the US, and therefore there could be total chaos. As is, US airlines expect a 4% disruption of daily flights. Clementine weather — particularly since it’s now peak winter — could worsen the situation.

The potential risk is rather serious, said aviation experts. The RTCA (formerly Radio Technical Commission for Aeronautics), a US-based private non-profit that issues technical aviation guidance, said there was “potential for broad impacts to aviation operations in the United States, including the possibility of catastrophic failures leading to multiple fatalities, in the absence of appropriate mitigations”.

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The FAA has warned that 5G interference may trigger issues in various systems aboard Boeing’s 787 Dreamliner. As a result, the plane could slow down on landing, thereby veering off the runway.

To mitigate these risks, the FAA is identifying altimeters which can be deployed in ‘5G areas’. Further, it has identified airports where GPS systems can replace radio altimeters for aircraft guidance. What the airlines want, however, is for 5G networks to be deactivated within 2 miles of affected airports.

Do the telecom firms agree?

Representatives of Verizon and AT&T have pointed out that C band 5G has done little harm in the roughly 40 other countries it has already been deployed in. Nevertheless, they have consented to buffer zones near 50 US airports for around six months to temper the risks. Such a step was adopted in France earlier.

An option would be for the telecom firms to go for lower frequency, but that would disrupt their services. The higher the spectrum frequency, the more efficient the telecom service. Verizon has clarified that though it holds spectrum with higher bandwidth, it will not use it for several years.

What the other nations are doing

In 2019, the EU formed guidelines for 5G frequencies in the 3.4-3.8 GHz range — lower than what the US is rolling out. This bandwidth has not triggered any issue so far in the EU.

South Korea similarly has rolled out 5G in the 3.42-3.7 GHz range. Though some of its 5G mobile communication wireless stations are close to airports, no problems have been reported till date.