Fight may not be over
As previously noted, there could be another showdown later this year when AT&T and Verizon lift temporary 5G restrictions around airports. One of the FAA’s statements this week seems to indicate that its approvals for altimeters are good for only as long as those voluntary restrictions are in place. “The new safety buffer announced Tuesday around airports in the 5G deployment further expanded the number of airports available to planes with previously cleared altimeters to perform low-visibility landings,” the FAA said on Wednesday.
If “previously cleared altimeters” can only work properly at airports with the newly announced buffer zone, then the FAA presumably hasn’t determined whether those altimeters will work after carriers deploy C-band 5G without the voluntary limits that go beyond FCC requirements.
We asked the FAA today if this means that the current approvals only apply for as long as the “safety buffer” and other temporary 5G limits are in place and whether new FAA approvals will be needed after temporary restrictions are lifted. The FAA did not answer those questions directly but told Ars, “The buffers around airports reduce 5G signal strengths and allow aircraft to land safely in low-visibility conditions. Prior to these buffers, the signal strength was too strong in certain areas for low-visibility landings to safely occur.”
Although the FAA said nothing about needing to grant new approvals later on, its answer today and the statement on Wednesday suggest that the agency is not ready to declare planes safe to land once temporary 5G limits are lifted.
“Wow. It does appear that we are set for another showdown in early July when the current restrictions are supposed to be lifted,” telecom consultant Tim Farrar told Ars today after we shared the FAA’s response with him. Farrar previously published a blog post analyzing what he called “the FAA’s fearmongering” and slow progress in approving altimeters.
On Twitter, Farrar wrote, “It appears clear from the FAA statements that all [approvals of altimeters] will be invalidated if the 5G deployment restrictions (‘safety buffer’) are removed.”
Feld was disappointed in the FAA’s response to Ars, saying that “it looks very much like a non-answer, which unfortunately has been consistent with everything the FAA has done until now.” The FAA has exhibited “passive-aggressive behavior where it simply refuses to commit to anything until it has its arms twisted” and is “constantly undermining the idea that there is any finality” with “statements that don’t definitively say no,” he said.
One of the first major concessions from AT&T and Verizon was to implement “C-band radio exclusion zones” around 50 US airports for six months, until July 5. The carriers also delayed their widespread rollout of C-band spectrum from December 5 to January 19.
The new safety buffer appears to be in addition to the previously agreed-to exclusion zones. “At our sole discretion, we have voluntarily agreed to temporarily defer turning on a limited number of towers around certain airport runways as we continue to work with the aviation industry and the FAA to provide further information about our 5G deployment, since they have not utilized the two years they’ve had to responsibly plan for this deployment,” AT&T told The Hill on Tuesday. AT&T explained further that it had “temporarily deferred turning on C-band transmitters within a two-mile radius of the airport runways specified by the FAA.” The two-mile radius was requested in the letter signed by Parker, Kirby, and other airline CEOs.
It’s not clear whether the safety buffer that carriers agreed to this week will expire on the same six-month timeline. AT&T told Ars today, “We will notify the FAA before any towers are activated within the additional buffer zone announced on Tuesday. We are continuing to engage with the FAA, FCC, and other stakeholders—including providing details about our deployments—to help facilitate the FAA’s technical assessments and clearance of aviation equipment.” We also contacted Verizon today and will update this article if we get more information.
T-Mobile also purchased C-band spectrum licenses at the FCC auction but isn’t deploying on the frequencies until late next year. “We don’t anticipate any limitations when we are ready to deploy it in late 2023,” T-Mobile said.
FAA has more testing to do
At a minimum, the FAA should already be testing altimeters against the levels of 5G transmissions that will occur near airports in July, Feld said. The FAA also needs to verify that altimeters can continue to work properly after AT&T and Verizon deploy in the upper C-band (from 3.8 GHz to 3.98 GHz) in 2023.
“At this point, it isn’t about hypothetical situations with an unknown set of altimeters… You know what the rules are. You know what the altimeters are. You know the date on which we’re going to revert to a different set of rules. How the hell can you not know whether these devices are safe or not under the new rules? The only way you can not know is if you refuse to know,” Feld said.
Feld also said he finds it “increasingly difficult to understand the FAA’s rationale around any of these things, especially given the statements from the [airline] CEOs who actually own and operate this equipment that ‘yeah we’ve done tests, and yeah there’s no problem.'”