The FAA could require some airlines to upgrade to 5G-friendly altimeters

After over a year of delays, concerns, and prohibitions, the 5G C-band deployments are still potentially causing some disruption in the world of airfare.

The FAA in January proposed a new rule requiring airlines to replace or retrofit the radio altimeters in their planes before a proposed deadline of February 1, 2024.

The proposed rules mark another development in a saga that began in December 2021, when the FAA set flight restrictions for pilots over fears that C-band 5G could potentially interfere with some cockpit safety systems.

The spat has been a thorn in the side of telcos, delaying C-band rollouts that they see as critical to expanding 5G networks and which they spent a collective $81.2 billion to secure the right to. Now, the FAA is looking to require airlines to replace certain altimeters due to concerns that 5G interference could cause altimeters to malfunction, issuing erroneous warnings to pilots about their altitude.

If the newly proposed rule from the FAA becomes a requirement, airline trade associations told us that airlines are “committed to complying” and ready to take on any potential costs associated with the upgrades, but that compliance is contingent on suppliers like Honeywell, Thales, or Raytheon manufacturing enough compliant parts before the proposed deadline.

“A4A member carriers are working diligently to ensure fleets are equipped with compliant radio altimeters, but global supply chains continue to lag behind current demand,” Marli Collier, communications manager at Airlines for America, told Emerging Tech Brew in an emailed statement. “Any government deadline must consider this reality.”

The FAA estimates that approximately 180 airplanes would require radio-altimeter replacements, and 820 airplanes would require the addition of a radio-altimeter filter at an estimated total cost of compliance of up to $26 million. Breaking down the cost, the FAA estimated that a full replacement would cost up to $80,000 per altimeter and $5,020 per altimeter filter, including parts and labor.

“AT&T and Verizon agreed in June 2022 to keep their voluntary mitigations in place until July 2023 to give the aviation industry an additional year to retrofit their airplanes with radio frequency filters. Although that work continues at an expedient clip, this proposed AD would make the retrofits mandatory for operators that have not completed the work,” FAA spokesperson Mina Kaji said in an emailed statement.

She added that this is a “this longer-term solution” that “will enable the wireless companies to achieve full use of their networks while maintaining aviation safety.”

As of now, the newly proposed rule applies to domestic carriers, but international carriers face similar deadlines in 2023 and 2024. In a November 2022 letter to the FAA, the International Air Transport Association (IATA) said supply-chain issues and American prioritization by radio-altimeter manufacturers could hamper efforts from international carriers to comply with the new rules before their July 2023 deadline.

So far, Taiwan-based China Airlines has already informed the FAA it won’t be able to upgrade its altimeters before the 2024 deadline, citing issues in the supply chain. China Airlines proposed the FCC extend the deadline further or consider case-by-case “alternate methods of compliance.”

Perry Flint, head of corporate communications, North America at the IATA, told Emerging Tech Brew there is an “equity issue” at play as airlines work to comply with the proposal.

“Every single piece of equipment on an aircraft has been certified-slash-approved by the FAA. That includes the existing radio altimeters,” Flint said. “So for the FAA, owing to a breakdown in intra-government communications working together, to come to the industry and say it is your job to fix a problem that you did not create and to pay for it yourself is simply unfair, and unreasonable. Nevertheless, that’s where we are.”