FAA Bulletin May Not Deter AT&T, Verizon on C Band

The FAA's air safety warning about 5G use on the C band (see 2110290065) is unlikely to cause delays to planned deployments on the frequency, experts told us. They still expect AT&T and Verizon to start deployments in 2021, as both work to close to their 5G spectrum gap with T-Mobile. CTIA now has a webpage addressing the issue. Observers noted the first spectrum deployed isn’t close to that used by radio altimeters.

Sen. Marsha Blackburn, R-Tenn., pressed FAA Administrator Stephen Dickson during a Wednesday Senate Commerce Committee hearing on aviation safety on the reasoning for the alert. The issue also factored into a Wednesday House Communications Subcommittee markup session (see 2111030064). Blackburn noted 39 other countries use the C band "for 5G services without any interference to aviation” and questioned whether the FAA was “taking this evidence into consideration.” Two dozen European countries have been using the C band and other frequencies for three years to accommodate 5G services and “they have had zero adverse occurrences and zero claims of interference,” Blackburn said.

“I need to make sure that the safety of the public is protected ,” Dickson said. “We are working very closely with the FCC” and the telecom industry and “we will figure this out so that 5G and aviation safety can coexist” without “an adverse impact to aviation safety.” Other countries’ 5G use of the C band differs from what’s planned in the U.S. “in terms of power levels and specific deployment locations,” so citing a lack of interference in those cases is “a bit of an apples-to-oranges comparison,” he said. The U.S.’ RTCA aviation safety group and the European Organisation for Civil Aviation Equipment are “looking very closely at these issues” and there’s an expectation that “there will be some modifications eventually over time that will need to occur to some of those avionics.”

Tuesday's special airworthiness information bulletin (SAIB) alerts aircraft manufacturers, radio altimeter manufacturers, operators and pilots of the planned deployment of 5G in the C band starting Dec. 5. The SAIB “recommends that radio altimeter manufacturers, aircraft manufacturers, and operators voluntarily provide to federal authorities specific information related to altimeter design and functionality, specifics on deployment and usage of radio altimeters in aircraft, and that they test and assess their equipment in conjunction with federal authorities.” Test results are to be reported “to the appropriate civil aviation authorities and spectrum regulators.” The FAA said it’s “collaborating” with the FCC and NTIA “to assess the need for mitigation beyond the recommended action in this SAIB.”

The Aerospace Industries Association (AIA), Air Line Pilots Association and other aviation groups and companies sent the FCC a letter, posted Wednesday in docket 18-122, asking the agency to demand more data from carriers. “Efforts are being made to provide pertinent” radio altimeter data “to the Commission and other interested parties,” the letter said: “There are still multiple unanswered questions for the 5G carriers, equipment manufacturers, and the Commission on the exact operational parameters of 5G networks.” AIA didn’t comment further.

“There is little chance that Verizon and AT&T will delay their C-band deployments in the A blocks,” BitPath Chief Operating Officer Sasha Javid told us. “These blocks, which are available in 46 of the largest [markets] starting in December, are critical to both carriers’ 5G plans and are no less than 400 MHz away from the frequencies used for radio altimeters. This is significantly further than the 100 MHz separation that exists between already deployed mobile broadband and radio altimeter operations in Japan.” AT&T and Verizon didn't comment.

The bulletin has “certainly escalated awareness of these C-band deployments in the aviation community,” Javid said. “This will undoubtedly put pressure on the FCC and FAA to address concerns well before the next C-band blocks become available in two years, as those could be as close as 220 MHz away from radio altimeters.”

The FAA bulletin is “mainly a data collection effort that should have been completed in 2017” when the FCC started to target the 3 GHz spectrum, said High Tech Forum founder Richard Bennett. “Better late than never, but these things need to be done more expeditiously,” he said: Problems are unlikely because 5G power levels are relatively low, he said.

“The FAA and the altimeter industry proved dreadful in trying to make cogent arguments during C-band's consideration, almost to a point of being laughable,” emailed former FCC Commissioner Mike O’Rielly. “Now, they want to falsely scare the American people to get what they couldn't convince the FCC or have any defensible data to support, when real facts and international experience completely disproves their empty concerns,” he said: “The impact on C-band licenses and 5G would be devastating -- basically invalidating licenses and halting deployment in the band at such a crucial time -- and would directly obliterate the spectrum auction process.”

The FAA won’t deter AT&T and Verizon from deploying “this time around, but I believe the FAA’s motives are designed to deter subsequent activities and perhaps small operators,” said Strand Consult Senior Vice President Roslyn Layton. “FAA wants to be the one to call the shots,” she said: “Collaboration is great, but we don’t have time to lose. We are in a race with China to get devices, services, and industries deployed on 5G. No other country having deployed 5G is losing time on this issue. It’s a regulatory smokescreen.”

The Aerospace Vehicle Systems Institute, meanwhile, “provided highly confidential information subject to protective order” to the FCC in the proceeding, said a Wednesday filing.