AT&T, Verizon delay 5G C-band rollout over FAA fears of passenger plane radars jammed by signals

Telcos miffed, pilots are fine with it

AT&T and Verizon have agreed to further delay the US rollout of their previously delayed 5G C-band wireless service only one day before the planned launch date.

On December 31, 2021, US Secretary of Transportation Secretary Pete Buttigieg and Federal Aviation Administration chief Steve Dickinson sent a letter [PDF] to AT&T CEO John Stankey and Verizon CEO Hans Vestberg warning of travel sector chaos if aviation industry concerns about 5G interference with aircraft equipment are not addressed by Wednesday, January 5, 2022 – the date the two companies previously said they'd start using the C-band spectrum.

The FAA has based its concern on an October 2020 report [PDF] from the Radio Technical Committee for Aeronautics (RTCA) that found "a major risk that 5G telecommunications systems in the 3.7-3.98 GHz band [used by 5G C-band] will cause harmful interference to radar altimeters on all types of civilian aircraft."

Worries that 5G signals may interfere with aviation equipment date back at least to 2015 when the International Mobile Telecommunications (IMT) first considered additional spectrum allocation for mobile wireless service.

The letter proposes a framework by which commercial C-band service can begin as planned except around major airports, to be identified by the FAA. Service around these priority airports would be phased in by the end of March 2022, barring unforeseen technical problems.

AT&T and Verizon had previously planned to make their respective 5G services available in the US last December, but delayed launching their services while discussions with the FAA remained ongoing.

Telcos aren't happy

On Sunday, Stankey and Vestberg rejected the concerns raised by Buttigieg and Dickinson. In a joint reply obtained by the New York Times [PDF], the two CEOs said while they care deeply about the safety of their customers, employees, and families, "the question of whether 5G operations can safely coexist has long been settled."

The response letter contends that "radio altimeters do not operate on, or anywhere near, the C-band frequencies," noting that altimeters operate on the 4.2-4.4 GHz frequency band. The C-band spectrum covers 3.7-3.8 GHz.

It goes on to chide the federal government and the FAA for waiting until November last year to begin collecting altimeter data and for asking the two companies to make additional accommodations just five days before their planned 5G deployment – for which the wireless industry paid $80bn in spectrum fees last year.

"Agreeing to your proposal would not only be an unprecedented and unwarranted circumvention of the due process and checks and balances carefully crafted in the structure of our democracy, but an irresponsible abdication of the operating control required to deploy world-class and globally competitive communications networks that are every bit as essential to our country's economic vitality, public safety and national interests as the airline industry," the CEOs' letter says.

As a concession, the two company leaders said they'd adopt C-band signal level reduction zones similar to those implemented around airport runways in France – where 5G service currently coexists with aviation – until July 5, 2022.

That same day, the FAA issued a statement indicating that proposals from wireless carriers were being reviewed as the agency tries to find a way for 5G C-band service to operate without harming aviation safety. The agency said while the situation remains unresolved, it may issue Notices to Air Missions (NOTAMs) that limit aviation in areas where 5G interference is possible.

Hitting pause

Evidently unwilling to take the blame for cancelled flights and stranded travelers, AT&T and Verizon on Tuesday said they would accept a brief delay.

"At Secretary Buttigieg's request, we have voluntarily agreed to one additional two-week delay of our deployment of C-band 5G services," an AT&T spokesperson said in a statement provided to The Register.

"We also remain committed to the six-month protection zone mitigations we outlined in our letter. We know aviation safety and 5G can co-exist and we are confident further collaboration and technical assessment will allay any issues."

"We’ve agreed to a two-week delay which promises the certainty of bringing this nation our game-changing 5G network in January, delivered over America’s best and most reliable wireless network," a Verizon spokesperson told The Register in an email.

Captain Joe DePete, president of the Air Line Pilots Association (ALPA), welcomed the delay in a statement emailed to The Register.

“It’s clear that this irresponsible rollout of 5G wasn’t ready for takeoff, and that’s why US Transportation Secretary Buttigieg, ALPA and other frontline aviation workers and stakeholders had called for a delay in implementation," he said. "We’re glad Verizon and AT&T were listening to the flight crew’s safety instructions."

"Now the real work begins. We are hopeful that this delay will enable the wireless industry and the broader aviation community to work together on effective solutions that will ensure that every passenger and cargo flight arrives safely without severe disruptions to aviation operations." ®