5G can interfere with aircraft's automatic landing system

6,834 aircraft in the US have received FAA guidance that when landing at an airport should not rely entirely on radio altimeter systems due to concerns about 5G waves. Radio altimeter systems are often used mainly during landings when pilots cannot see the ground clearly due to bad weather.

Lynn Lunsford, an FAA spokeswoman, said the agency was concerned that 5G signals could affect the accuracy of aircraft radio altimeters. Therefore, to limit the risk to aircraft when landing in bad weather, the FAA is working with wireless network operators and interagency partners to find ways to mitigate the problem.

The US Federal Aviation Administration says the aircraft radio altimeter and 5G C-band (which has a frequency range of 3.3 GHz to 4.2 GHz) do not operate on the same band but are close enough to may interfere with each other.

Currently, both US carriers, Verizon and AT&T, have suspended the use of C-band on 5G towers near the airport. To overcome this situation, airlines are also starting to consider installing band filters on radio altimeters, but it will take years for mass deployment.