The FAA Is Concerned Enough About 5G’s Potential To Affect Radar Altimeters That It Issued A Directive The wireless communication revolution is slated to arrive with commencement of 5G signals broadcasting in the U.S. on December 5. Many will herald it as progress but the FAA is warning that 5G signals could interfere with the radar altimeters that airliners, bizjets and other aircraft rely on.