FAA to require airplanes to upgrade altimeters by early 2024

The U.S. Federal Aviation Administration (FAA) will require both cargo and passenger airplanes in the U.S. to install 5G C-band tolerant radio altimeters, or an approved radio frequency (RF) filter, by February 24, 2024.

In a statement to FierceWireless, the FAA said that this latest directive is an update to the FAA’s December 2021 requirement that prohibited passenger and cargo planes from operating in the vicinity of 5G C-band wireless transmitters unless they were approved by the FAA.

To give the airlines more time to upgrade their altimeters and to allow normal flight operations to continue, Verizon and AT&T responded to the FAA’s December 2021 directive by voluntarily modifying their 5G C-band deployments. Both companies agreed to use lower power transmitters and incorporate buffer zones around airports.

The FAA said that airlines are making progress at retrofitting their airplanes to accommodate the 5G C-band transmissions, but added that this longer term solution makes the retrofits mandatory. In addition, the FAA is requiring airlines to revise their flight manuals to prohibit low-visibility landings after June 30, 2023, unless the retrofits have been completed on that airplane.

The FAA said that it collaborated with “wireless companies, aviation stakeholders and other federal agencies, including the Federal Communications Commission and the National Telecommunications and Information Administration,” on this solution.  The directive will be open to public comment for 30 days after it posts in the Federal Register.

This latest FAA directive likely comes as a welcome relief to AT&T and Verizon, which have been unable to fully use their 5G C-band spectrum assets in areas around airports. Both operators implemented 5G buffer zones around certain airport runways and also limited their 5G C-band power levels around airports.

In addition, this latest FAA directive will likely impact UScellular and other smaller telecom operators that hold C-band spectrum licenses and are currently planning their 5G C-band deployments. UScellular has said that it was in discussions with the FAA ahead of its planned C-band deployment and said that it had determined that only a small number of airports fall within UScellular’s footprint.