FAA announced large, long-range wide-body airliners, including Boeing 747S and Boeing 777S, are subjected to 5G interference. The agency has issued safety directives for both planes. 

The rollout of 5G has been a big mess in American skies. AT&T and Verizon began deploying the new high-speed cellular network on Jan. 19 while agreeing to create buffer zones around certain airports. 

The crux of the problem lies in the aircraft's radar altimeter uses frequencies close to C-band. 5G towers also use C-band radio spectrum frequencies that have the potential to disrupt radar altimeters, an important device on aircraft that informs the pilot of the altitude.