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New swaths of C-band cellular radio spectrum will help make the 5G hype closer to reality, but the big mid-band 5G rollout may have a side effect. The FAA is telling 6,834 airplanes to not land at certain airports because of 5G interference, because they rely on radio altimeters to tell how high they are above the ground.
The FAA ruled on Tuesday that many of the guided and automatic landing systems that are designed to work in poor visibility conditions will not be able to be used by the thousands of US planes. During periods of low visibility, landings could be limited due to concerns that the 5G signal could interfere with the accuracy of an airplane's radio altimeter.
These limitations could cause flight diversions and prevent dispatch of flights.
Flight delays are likely because of the limitations that could prevent flights from being dispatched to certain locations with low visibility.
An FAA spokesman tells us that they are working with the wireless operators to make sure the mitigations are tailored to prevent disruptions.
The FAA ruling gives airlines and pilots an out if they can prove that their airplanes are protected from interference and that they are not going to be affected by it. The airlines pointed us to the Airlines for America industry group, but they wouldn't comment on expected delays.
It is not clear which airports will restrict low visibility flights, but you can imagine that they would be in the same places where the carriers are installing 5G. In December, there were 46 markets designated as partial economic areas, including 1-4, 6-10, 12- 19, 21-41, and 43-50. You can see them all here. Notices will be issued for specific airports later.
The launch of the C-band was pushed back by one month, and AT&T offered to dial back the power of 5G towers for six months to address concerns. The FAA has not been convinced by the suggestion that there isn't a valid reason to fear interference. The FAA did not send a letter to the FCC on Monday suggesting that AT&T and Verizon's proposed power limits don't go far enough for safety. The FAA is not the entity that regulates wireless interference.
The bands are close enough that the fear exists, even though they don't actually operate in the same band. It might take years to certify the band filters and retrofit the planes, according to the Radio Technical Commission for Aeronautics.
