FAA Issues 5G ADs


The FAA has issued two airworthiness directives (ADs) requiring flight manual revisions “to incorporate limitations prohibiting certain operations requiring radio [also called radar] altimeter data when in the presence of 5G C-Band interference.” The ADs stem from concerns that the planned rollout of wireless broadband operations in the 3.7-3.98 GHz frequency band (5G C-Band) could adversely impact radar altimeters, which operate in the 4.2-4.4 GHz frequency range. The ADs, one of which applies to transport and commuter category airplanes (PDF) and the other to helicopters (PDF), stipulate that the locations affected will be identified by future Notices to Air Missions (NOTAMs). The FAA also published a Special Airworthiness Information Bulletin (SAIB) concerning the potential effects of 5G deployment on radar altimeters last month (PDF).

“The FAA believes the expansion of 5G and aviation will safely co-exist,” the agency said in a statement. “Today, we took an important step toward that goal by issuing two airworthiness directives to provide a framework and to gather more information to avoid potential effects on aviation safety equipment. The FAA is working closely with the Federal Communications Commission and wireless companies, and has made progress toward safely implementing the 5G expansion.”

Delayed from the original rollout date of Dec. 5, 2021, deployment of the 5G C-Band wireless broadband network is currently expected to begin in 46 major U.S. metropolitan areas starting Jan. 5, 2022. Following the issuance of the ADs, a coalition of aviation organizations led by the Aerospace Industries Association (AIA) released a statement urging “a further delay in 5G deployment for the data sharing and consultations necessary to create a win-win situation for both industries.” In addition to AIA, the groups participating in the coalition include the Air Line Pilots Association (ALPA), Experimental Aircraft Association (EAA), Helicopter Association International (HAI), Aircraft Owners and Pilots Association (AOPA), National Business Aviation Association (NBAA), General Aviation Manufacturers Association (GAMA) and International Air Transport Association (IATA).

“We appreciate the FAA’s efforts to find a safe solution for aviation and successful deployment of 5G,” the coalition said in its statement. “While we are currently evaluating the airworthiness directives and preparing to fully abide by them to ensure that aviation operations remain safe, we also expect significant disruptions to the national aviation system due to the rollout of 5G technologies in the C-band unless the FCC acts to mitigate the concerns. … Our coalition continues to call for a long-term solution that will protect the flying public by ensuring radio altimeters operate accurately while allowing 5G to roll out safely.”

Kate O'Connor
Kate O’Connor works as AVweb's Editor-in-Chief. She is a private pilot, certificated aircraft dispatcher, and graduate of Embry-Riddle Aeronautical University.

Other AVwebflash Articles


  1. Wait, they KNOW that 5G has radio interference affecting flight safety of transport and commuter planes, so it’s the job of the FCC to stop the rollout till the phone companies can fix their interference, right?

  2. I doubt the FCC will take any action until some congressperson or senator is unable to get into DCA (their personal airport) due to this 5G issue, and has to land at a less congressional convenient airport.

  3. Clash of the intractable interests! Watch as the great & powerful deploy their agencies on the field of combat! Bring popcorn 🍿

    • True…

      However, I don’t recall many fatalities from the simple use of a phone. Now if that Member of Congress is involved in a crash (See Matt W’s comment above)…and killed or injured, or if an airliner full of people has a traceable mishap the debate will take on real significance. ‘Til then… it’s all theoretical and of no interest.

    • Maybe, but one thing is certain: The solution will cost airplane operators more than it will wireless providers.

  4. “limitations prohibiting certain operations requiring radio [also called radar] altimeter data when in the presence of 5G C-Band interference.”

    How will this help? How is a pilot supposed to know that there is interference? How is one supposed to know where the 5G towers are?

    • According the article – “stipulate that the locations affected will be identified by future Notices to Air Missions (NOTAMs). “

  5. Perhaps our “Neighbors To The North” (Canada) have the most reasonable approach: Canada prohibits any cell phone towers or 5G activities within 5 miles of any public airport.

  6. From what I have seen is, the problem is more of a matter of the radar altimeters having a very wide front end, making them susceptible to interference from the devices that are 200 MHz to 700 MHz away. Remember the entire VHF aviation band is only 29 MHz wide.

  7. As with the 737Max issue, looks like there will have to be a fatality with this issue for action to happen.
    Oh yes, we learn from history, don’t we?