AT&T, Verizon Propose C Band Power Limits to Address FAA 5G Air Safety concerns

AT&T and Verizon said today that they would limit some of their 5G wireless services for six months while federal regulators review the signals’ effect on aircraft sensors, an effort to defuse a conflict about C band interference that has roiled both industries.

The cellphone carriers detailed the proposed limits Wednesday in a letter to the Federal Communications Commission (FCC). The companies said they would lower the signals’ cell-tower power levels nationwide and impose stricter power caps near airports and helipads, according to a copy reviewed by The Wall Street Journal.   This comes after, both companies agreed to push back their 5G C band rollouts by an additional month to January 5, 2022 after the FAA issued a Nov. 2 bulletin warning that action may be needed to address the potential interference caused by the 5G deployment.

“While we remain confident that 5G poses no risk to air safety, we are also sensitive to the Federal Aviation Administration‘s desire for additional analysis of this issue,” the companies said in the letter to FCC Chairwoman Jessica Rosenworcel.

“Wireless carriers, including AT&T and Verizon, paid over $80 billion for C-band spectrum—and have committed to pay another $15 billion to satellite users for early access to those licenses—and made those investments in reliance on a set of technical ground rules that were expressly found by the FCC to protect other spectrum users.”

AT&T and Verizon said they had committed for six months to take “additional steps to minimize energy coming from 5G base stations – both nationwide and to an even greater degree around public airports and heliports,” and said that should address altimeter concerns.

Wireless industry officials have held frequent talks with FCC and FAA experts to discuss the interference claims and potential fixes, according to people familiar with the matter. An FCC spokesman said the agreed-upon limits “represent one of the most comprehensive efforts in the world to safeguard aviation technologies” and the agency will work with the FAA “so that 5G networks deploy both safely and swiftly.”  Wireless groups argue that there have been no C-Band aviation safety issues in other countries using the spectrum.

Earlier this month, the Federal Aviation Administration (FAA) warned it could restrict U.S. airspace in bad weather if the networks were turned on as planned in December. The FAA warning came in the thick of cellphone carriers’ network upgrade projects.  A spokesman for the FAA called the proposal “an important and encouraging step, and we are committed to continued constructive dialogue with all of the stakeholders.” The FAA believes that aviation and 5G service in the band telecom companies have planned to use can safely coexist, he said.

AT&T and Verizon said they would temporarily lower cell-tower power levels for their 5G wireless services nationwide.

Photo Credit: GEORGE FREY/AGENCE FRANCE-PRESSE/GETTY IMAGES

Wireless industry executives don’t expect the temporary limits to seriously impair the bandwidth they provide customers because networks already direct signals away from planes and airport tarmacs, according to another person familiar with the matter.

Still, the voluntary limits are a rare step for wireless companies that place a high value on the spectrum licenses they hold. U.S. carriers spent $81 billion to buy licenses for the 5G airwaves in question, known as the C-band, and spent $15 billion more to prepare them for service this winter.

The carriers earlier this month delayed their rollout plans until early January after FAA leaders raised concerns about the planned 5G service. Air-safety officials worried the new transmissions could confuse some radar altimeters, which aircraft use to measure their distance from the ground.

At an industry event last week, FAA Administrator Steve Dickson said conducting flights in a safe manner and tapping spectrum for 5G services can both occur. He said the question was how to “tailor both what we’re doing in aviation so that it dovetails with the use of this particular spectrum.”  Mr. Dickson said another focus is the use of the spectrum in other parts of the world and how it differs compared with the U.S. “That’s what the discussions are that we’re having with the telecoms right now.”

U.S. wireless companies send 5G signals over lower frequencies than the altimeters, but air-safety officials worried that some especially sensitive sensors could still pick up cell-tower transmissions. Regulators in Canada and France have also imposed some temporary 5G limits.

The carriers’ letter said the mitigation measures would provide more time for technical analysis “without waiver of our legal rights associated with our substantial investments in these licenses.”

C-band limits are most relevant to AT&T and Verizon, which paid premiums to grab licenses for the new signals ready for use in December 2021. The companies still plan to launch their service, subject to the new limits, in January 2022. The proposed limits would extend to July 6, 2022 “unless credible evidence exists that real world interference would occur if the mitigations were relaxed.”

Rival carrier T-Mobile US Inc. is less vulnerable to delay because it spent a smaller amount for licenses that are eligible for use in December 2023. It also controls a swath of licenses suitable for 5G that aren’t subject to air-safety claims.

It’s not yet clear whether the proposal will be accepted by the FAA, which has warned pilots of the possibility that “interference from 5G transmitters and other technology could cause certain safety equipment to malfunction, requiring them to take mitigating action that could affect flight operations.” After July 6th, both carriers say they’ll set everything back to normal “unless credible evidence exists that real-world interference would occur if the mitigations were relaxed.”

“Our use of this spectrum will dramatically expand the reach and capabilities of the nation’s next-generation 5G networks, advancing US leadership, and bringing enormous benefits to consumers and the US economy,” Verizon and AT&T claimed in their joint letter sent to the FCC.

The federal agencies and the companies they oversee are meanwhile stuck in what New Street Research analyst Blair Levin called “a deep state game of chicken” guided by each regulator’s particular interest, with no clear path towards resolution.

References:

https://www.wsj.com/articles/at-t-verizon-propose-5g-limits-to-break-air-safety-standoff-11637778722

https://www.wsj.com/articles/fight-over-5g-and-aviation-safety-clouds-big-outlays-made-by-at-t-verizon-11636894800?

https://www.bloomberg.com/news/articles/2021-11-24/at-t-and-verizon-to-cut-5g-power-to-meet-aviation-safety-worries

https://www.reuters.com/technology/att-verizon-agree-new-precautions-address-5g-air-safety-concerns-2021-11-24/

 

C-Band 5G’s Threat to Aviation

Analysis: FCC’s C band auction impact on U.S. wireless telcos

Importance of FCC C Band Auction for 5G in the U.S.

https://transportation.house.gov/news/press-releases/committee-leaders-urge-fcc-to-act-to-protect-aviation-safety-amid-5g-broadband-implementation

 

5 thoughts on “AT&T, Verizon Propose C Band Power Limits to Address FAA 5G Air Safety concerns

  1. Thanks for the summary on this issue which the FCC could have been more proactive about earlier. For instance, as suggested in the referenced Viodi article, the FCC could have coordinated a pilot program to measure the real-world impact of the 5G radios on altimeters.

    Hopefully, the various players (e.g. FAA, FCC, industry) will come together to create this type of environment in the next 6 months to create a real-world pilot testing program. Six months is not a lot of time to pick sites, determine a test plan, measure, and report. They better get going.

    Lastly, to put things in perspective, the FCC’s Report and Order for auctioning the C-Band was issued on March 3rd, 2020. The auction launched on December 8th, 2020. RTCA formed a special committee of industry and the FAA to investigate the potential impact of C-Band licensing for 5G shortly after the FCC’s March 2020 Report and Order and issued their report on October 7th, 2020, approximately 7-months after the FCC Report and Order.

  2. AT&T’s Jeff McElfresh said that worries over the operator’s midband 5G delay have been “somewhat overblown.” He added that temporary tweaks to the operator’s network will not have a “major impact” on its customers.

    “I have a lot of confidence we will work through this,” McElfresh said Tuesday during an investor event.

    McElfresh is the CEO of AT&T Communications, the division of the company in charge of selling 5G and fiber Internet connections.

    AT&T’s Jeff McElfresh said that worries over the operator’s midband 5G delay have been “somewhat overblown.” He added that temporary tweaks to the operator’s network will not have a “major impact” on its customers.

    “I have a lot of confidence we will work through this,” McElfresh said Tuesday during an investor event.

    McElfresh is the CEO of AT&T Communications, the division of the company in charge of selling 5G and fiber Internet connections.

    https://www.lightreading.com/5g/atandts-networking-chief-downplays-c-band-delay-in-5g/d/d-id/773799?

  3. US aviation groups are warning that the deployment of certain 5G mobile networks in the country could result in disruption to flights, including delays to air cargo shipments.

    The Aviation 5G Coalition, an industry consortium representing airlines, manufacturers and associations, said that AT&T and Verizon will activate their C-Band 5G on January 5.

    The group is not against the use of 5G but claimed that transmissions in the “C-Band” could interfere with radar altimeters when deployed close to airports.

    In response, the FAA has issued an order prohibiting many flight operations related to poor weather landings when C-Band 5G networks are within a certain range of airports.

    “Airlines operate safely in these conditions today but will be prohibited from operating in them if C-Band 5G is transmitted near the airport,” the group said.

    Potential impacts include delayed and cancelled passenger flights; delayed air cargo shipments; significant schedule disruptions; and inability for first responders, military, and law enforcement to fly helicopter missions.

    In a joint statement, the members of the Aviation 5G Coalition said: “Time is running out before millions of air travellers and the shipping public experience significant disruptions such as flight delays, flight cancellations and backups to the already-stressed supply chain.

    “We implore the Federal Communications Commission, Federal Aviation Association (FAA) and National Economic Council to continue meaningful discussions in good faith and to identify mitigations and reach a successful implementation plan that will ensure new 5G technologies can safely co-exist with the aviation industry.

    “We strongly believe that by working together these groups can create a win-win situation for all stakeholders – the telecommunications industry, the aviation industry and most importantly the millions of customers who depend on our services every day across the country.”

    The group has tabled its own set of counter proposals that it hopes will offset the concerns.

    HKSG Media Ltd.

  4. Dec 23, 2021 Update from Bloomberg:

    U.S. aviation regulators on Thursday expanded their warning about 5G service set to launch Jan. 5 on new frequencies, saying potential interference could have a broad impact on aircraft safety systems.

    The Federal Aviation Administration issued a Safety Alert for Operators warning that “a wide range” of aircraft safety devices could malfunction and laid out the process it will follow in coming days to potentially issue specific restrictions on flights.

    he FAA actions come as telecommunications and aviation companies agreed on Wednesday to share more data in an attempt to head off what has become a tense standoff over whether the 5G service could disrupt airlines and helicopter operations.

    “The FAA is working with the aviation and wireless industries to find a solution that allows 5G C-band and aviation to safely coexist,” the agency said in a statement that accompanied the release of the alert and a Special Airworthiness Information Bulletin.

    In the alert, the FAA identified 17 different safety systems and aircraft functions that could fail if 5G airwaves interfere with radar altimeters, which use radio waves to calculate an aircraft’s altitude.

    As talks with the telecommunications industry are underway, the FAA is preparing what are known as Notices to Air Missions that may restrict flights in dozens of locations, it said.

    The wireless industry and the Federal Communications Commission have said the new high-speed wireless service on the so-called C-band of spectrum don’t pose a threat, but the FAA and airlines are warning that there could be flight disruptions including delays and the diverting of planes to different airports. C-band airwaves are near the frequencies used by altimeters.

    “We share the FAA and FCC’s confidence that we can and will have safe flights and robust and reliable 5G,” Nick Ludlum, a spokesman for the CTIA telecommunications trade group, said in an email. “We continue to work closely with the aviation industry and we look forward to joining the nearly 40 countries already operating 5G in the C-band on January 5th.”

    A radar altimeter’s data is fed into numerous systems on aircraft, from basic help to pilots during landing to multiple safety devices, according to the FAA. Its data is used to prevent crashes into the ground and mid-air collisions, for example. But it also feeds aircraft automation that control throttle settings, takeoff guidance, windshear alerts and thrust reversers that help stop after landing.

    “Anomalous (missing or erroneous) radio altimeter inputs could cause these other systems to operate in an unexpected way during any phase of flight – most critically during takeoff, approach, and landing phases,” the FAA said in the safety alert.

    https://www.bloomberg.com/news/articles/2021-12-23/safety-alert-on-5g-interference-with-aircraft-expanded-by-faa

  5. Another update: AT&T, Verizon Refuse FAA Request to Delay 5G Launch

    AT&T and Verizon rebuffed a request from federal transportation officials to voluntarily delay the launch of new 5G wireless services, extending a showdown that could lead to potentially disruptive U.S. flight restrictions as soon as this week.

    The cellphone carriers on Sunday offered a counterproposal that would further dim the power of their new 5G service for six months to match limits imposed by regulators in France, giving U.S. authorities more time to study more powerful signals’ effect on air traffic. The companies had planned to launch the service Wednesday in as many as 46 of the nation’s largest metropolitan areas.

    “If U.S. airlines are permitted to operate flights every day in France, then the same operating conditions should allow them to do so in the United States,” the chief executives wrote in a letter reviewed by The Wall Street Journal.

    The Federal Aviation Administration has been preparing to issue flight restrictions that could go into effect around the country as soon as Wednesday. The limits could restrict pilots from using certain automated systems to help land aircraft in bad weather, a move that could disrupt air travel and cargo shipments.

    “U.S. aviation safety standards will guide our next actions,” the FAA said Sunday. The agency declined to comment about when it might issue the flight limits in official notices to air missions.

    Telecom-industry officials have pointed to dozens of countries, including France, that have already allowed cellular service over parts or all of the frequencies in question, known as C-band. France is among the countries that have imposed wireless limits near airports while regulators study the effect the signals have on aircraft.

    The letter by AT&T CEO John Stankey and Verizon CEO Hans Vestberg was in response to one sent by Transportation Secretary Pete Buttigieg and Federal Aviation Administration chief Steve Dickson late Friday. The New Year’s Eve missive asked the carriers to postpone their planned 5G launch by “no more than two weeks” while officials worked to address the wireless services’ effect on specific airports over the coming weeks.

    Air-safety regulators have said the new cellular services could confuse key cockpit safety systems and have been preparing to impose potentially disruptive flight restrictions.

    AT&T and Verizon, which combined serve more than half of all U.S. cellphone connections, disputed officials’ claims of air-safety risks. The companies postponed a planned December debut of the new signals to provide more time for telecom and aviation regulators to share information about the wireless infrastructure and aircraft equipment in question.

    Wireless companies later pledged to limit C-band signals for another six months through early July. The letter Sunday proposed even stricter 5G limits over the same period.

    But the telecom CEOs said transportation regulators’ latest delay request would be to “the detriment of millions of our consumer, business and government customers.” The CEOs added that carriers spent more than $80 billion to acquire the licenses in a Federal Communications Commission auction that closed in January 2021.

    FCC authorities padded the spectrum they auctioned with a swath of buffer frequencies to prevent interference with cockpit systems. But air-safety regulators have expressed concern that more sensitive altimeters could mistake cellular transmissions for terrain.

    AT&T and Verizon have spent the past year preparing to turn on new signals to provide new fifth-generation wireless technology, a faster and more capable mobile service. Wireless companies in other countries already use similar frequencies, but the spectrum wasn’t available to U.S. providers until recently.

    Without a resolution to the dispute, Messrs. Buttigieg and Dickson warned the FAA’s flight limits would bring severe economic consequences.

    “Failure to reach a solution by Jan. 5 will force the U.S. aviation sector to take steps to protect the safety of the traveling public, particularly during periods of low visibility or inclement weather,” they wrote in their Dec. 31 letter.

    Airlines have been bracing for significant flight cancellations and diversions due to potential FAA flight restrictions because of the regulator’s aviation-safety concerns. Pilots and airlines had been awaiting details of potential FAA flight restrictions that limit the use of systems that rely on radar altimeters.

    Over the past week, U.S. air travel has been snarled by a mix of winter storms and staffing challenges because of increasing ranks of airline crews calling in sick with Covid-19 as the U.S. deals with a surge by the Omicron variant. Thousands of flights have been canceled and delayed.

    The competing proposals are the latest in a flurry of behind-the-scenes work by aerospace manufacturers and wireless companies, their regulators and senior White House officials. As they attempted to hammer out solutions to allow the new 5G service to go live without prompting severe flight restrictions, the trade group Airlines for America asked the FCC to consider an emergency request to delay the wireless rollout.

    The airline trade group said Sunday it continued to urge the FCC and telecom industry to work with the FAA and aviation industry to reach a compromise.

    The FCC is an independent agency that acts outside the Biden administration’s direct authority. The commission hasn’t shown an interest in limiting licenses that it found safe to grant in a 2020 order authorizing the 5G auction.

    An FCC spokeswoman declined to comment on the airline group’s request but said the commission remained optimistic that “by working together we can both advance the wireless economy and ensure aviation safety.”

    https://www.wsj.com/articles/at-t-verizon-refuse-faa-request-to-delay-5g-launch-11641146719?mod=hp_lead_pos2

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