Carriers are satisfied‚ but airlines object
Verizon said the latest development will let it “make full use of our C-Band spectrum for 5G around airports on an accelerated and defined schedule. Under this agreement reached with the FAA, we will lift the voluntary limitations on our 5G network deployment around airports in a staged approach over the coming months meaning even more consumers and businesses will benefit from the tremendous capabilities of 5G technology.” Verizon said the deal “is the result of months of close collaboration with the FAA, FCC, and aviation industry.”
AT&T said that “close coordination with the FAA over the last several months” has helped the carrier develop “a more tailored approach to controlling signal strength around runways that allows us to activate more towers and increase signal strength.”
“Though our FCC licenses allow us to fully deploy much-needed C-Band spectrum right now, we have chosen in good faith to implement these more tailored precautionary measures so that airlines have additional time to retrofit equipment. We appreciate the FAA’s support of this approach, and we will continue to work with the aviation community as we move toward the expiration of all such voluntary measures by next summer,” AT&T said.
Airlines for America, a trade group that represents the major US airlines, is not so happy. “We have serious concerns that the Federal Aviation Administration (FAA) has placed the burden on the aviation industry to act in a way that would previously be considered, by the FAA itself, to be reckless in the context of design changes to safety-critical avionics,” the group told FAA Acting Administrator Billy Nolen in a letter on Friday. The letter was posted on Twitter by Reuters reporter David Shepardson.
“At today’s FAA roundtable we were told that the vast majority of our fleet (approximately 4,800 aircraft) would need to be retrofitted by July 2023,” Airlines for America also wrote. “Given that the FAA has not even approved solutions nor have manufacturers manufactured these products for most of this fleet, it is not at all clear that carriers can meet what appears to be an arbitrary deadline.” The trade group accused the FAA of “acced[ing] to the demands of the telecommunications companies.”
In Friday’s FAA announcement, Nolen said the compromise is fair. “We believe we have identified a path that will continue to enable aviation and 5G C-band wireless to safely co-exist,” he said. “We appreciate the willingness of Verizon and AT&T to continue this important and productive collaboration with the aviation industry.” Nolen became the acting FAA head in March, after the resignation of Administrator Steve Dickson.
FCC considers crackdown on bad receivers
Airlines for America argued that the 220 MHz guard band isn’t enough because 5G transmissions use “such high power that significant bleed-over to the radio altimeter band is inevitable.” The 220 MHz guard band is really 400 MHz in practice this year because AT&T and Verizon are not yet deploying above 3.8 GHz.
The altimeter design problem goes back decades. “Fundamentally, the problem is a design issue with the aviation industry’s radar altimeters,” Dennis Roberson, who runs a technology consulting firm and is a research professor at Illinois Institute of Technology, told lawmakers during a House subcommittee hearing in February.
When altimeters were designed, “they had very low-power neighbors, i.e., satellites beaming their information to the earth from very distant orbits… This led the early designers of the altimeters to decide they really could ignore their assigned spectrum boundaries, and as a result they allow transmitted energy far outside their band into the receiver,” Roberson explained.
The aviation industry’s slowness in fixing altimeters may lead to the FCC cracking down on bad wireless receivers. In April, the FCC voted unanimously to launch an inquiry into poorly designed wireless devices that receive transmissions from outside their allotted frequencies.
The inquiry could result in new receiver regulations similar to the rules that already require wireless devices to transmit only in their licensed frequencies. “To avoid harmful interference, we typically have rules about how and when transmitters can operate,” FCC Chairwoman Jessica Rosenworcel said at the April meeting. “But wireless communications systems involve transmitters and receivers… so we need to rethink our approach to spectrum policy and move beyond just transmitters and consider receivers, too.”