The FAA issued an airworthiness directive (AD) on Tuesday prohibiting Boeing 747-8, 747-8F and 777 aircraft from landing at airports where Verizon and AT&T’s 5G C-Band wireless broadband networks could cause radar altimeter interference. The AD requires airplane flight manual (AFM) revisions to add limitations prohibiting dispatching or releasing affected aircraft “to airports, and approaches or landings on runways, when in the presence of 5G C-Band interference as identified by Notices to Air Missions (NOTAMs).” As previously reported by AVweb, the FAA has published more than 1,400 Notices to Air Missions (NOTAMs) related to potential 5G interference with radar altimeters.
“The FAA issued the AD because many systems on Boeing 747-8, 747-8F and 777 aircraft rely on the altimeter, including autothrottle, ground proximity warning, thrust reversers and Traffic Collision Avoidance System,” the agency said in a statement.
The AD (PDF) is expected to affect around 335 aircraft in the U.S. and 1,714 worldwide. The FAA emphasized that it does not apply to landing at airports where the agency has determined that aircraft altimeters are safe and reliable in the 5G C-band environment nor to airports where 5G isn’t deployed. Compliance time for the AD is within two days of when it is officially published in the Federal Register, which is currently scheduled for Jan. 27.