This article presents a cautionary tale about how the failure of interagency coordination between the Federal Communications Commission (FCC or Commission) and the Federal Aviation Administration (FAA) created an avoidable interagency conflict and ensuing crisis in the timely deployment of 5G wireless services over the C-band spectrum in the 3.7–3.98 GHz range of the electromagnetic spectrum. This 11th-hour crisis, unique to the United States, occurred more than four years after the FCC first initiated proceedings inviting comment by all parties on the use of this spectrum and more than a year after the federal government reaped billions of dollars from the public auction of that spectrum for the specific use of 5G service deployment. This cautionary tale highlights a need for better interagency coordination specifically on spectrum issues in view of the incessantly growing demand for broadband capacity, but even more generally on other issues among all federal agencies, particularly as our nation grapples with the challenges presented by climate change.
The C-band controversy has its roots in the ever-increasing—and, by all appearances, insatiable—demand for wireless broadband services. In just the last few years, demand for 5G wireless services in the United States and globally has increased exponentially, reflecting 5G technology’s ability to significantly increase wireless communications performance and offer unparalleled opportunities for innovation. Critical to the deployment of 5G by our nation’s wireless broadband service carriers is use of a particular portion of the electromagnetic spectrum, the 3.7–4.2 GHz band, also known as the “C-band.”
While mobile traffic continues to surge in many areas of the United States, some communities still lack access to efficient wireless broadband connectivity. Wireless networks in the United States, and around the world for that matter, began transitioning to 5G services in 2018–2019 because 5G services enhance the performance and volume of wireless broadband communications while offering new, unparalleled services. In particular, 5G technology allows for innovative services in the areas of health care, transportation, agriculture, education, and more.
Because 5G networks have the potential ability to “transform our economy, boost economic growth, and improve our quality of life,” U.S. policy makers and government officials undertook initiatives to promote deployment of 5G services in the United States and to avoid the prospect that the United States might lag behind China and other countries in deploying 5G services. Numerous observers attributed the risk that the United States might lag other countries in 5G deployment to the potential lack of access by U.S.-based 5G networks and service providers to radio frequencies that are viewed as the best fit for 5G—in other words, the C-band.
In August 2017, the FCC initiated a notice of inquiry (2017 Mid-Band NOI) into making the C-band, as well as two other bands in the mid-band portion of the electromagnetic spectrum, available for 5G terrestrial wireless broadband services, and invited comments from all interested parties. After completing the NOI proceeding, the FCC in July 2018 initiated a formal notice of proposed rulemaking (C-Band NPRM) to establish rules for the licensing and use of the C-band for terrestrial broadband services employing 5G technology.
As part of the rulemaking process, the FCC solicited and examined over a 20-month period numerous comments, information, and data submissions from all interested parties regarding the manner, terms, and conditions upon which it should make the C-band available for 5G-based terrestrial broadband services deployment. The information submitted to the FCC contained details regarding the potential impacts, such as safety impacts on users and uses of spectrum bands adjoining the C-band, including the 4.2–4.4 GHz band reserved globally for use by aircraft radio altimeters and aircraft wireless avionics intra-communications (WAIC) systems.
In March 2020, the FCC issued its C-Band Order, in which it adopted and released for publication in the Federal Register rules to authorize the provision of terrestrial broadband services in the 3.7–3.98 GHz portion of the C-band and to conduct a public auction for licenses to use that part of the C-band for terrestrial broadband services. As part of its order, the FCC also adopted technical rules to ensure that 5G terrestrial broadband services using that portion of the C-band would not interfere with radio altimeters using the nearby 4.2–4.4 GHz frequency band for aeronautical navigation.
Radio altimeters are important components of an aircraft’s navigation systems and provide data about the aircraft’s height above terrain and water. However, the data submitted to the FCC, including data submitted by aviation interests, strongly indicated that the potential for interference with radio altimeter function by 5G broadband service networks operating in the lower portion of the C-band could occur only if those radio altimeters failed to properly filter out signals occurring substantially below—220 megahertz below—the spectrum band in which the altimeters were licensed to operate. Thus, the FCC, as the federal agency with the sole authority to control public airwaves and address potential spectrum interference issues involving nongovernment parties, expressly stated that it “expect[ed] the aviation industry to take account of” the upcoming deployment of 5G services operating within the C-band. The FCC specifically encouraged the aviation industry to “take appropriate action, if necessary, to ensure protection of [radio altimeters]” and upgrade any altimeters that were not “well designed”— that is, that poorly filtered out frequencies outside the part of the spectrum that was designated to them.
The FCC’s C-band rules were published in the Federal Register in April 2020. Notably, while certain parties sought reconsideration with the FCC, as well as appellate review of those rules within the 60-day statutory deadline for filing a petition for review with a federal court of appeals, neither the U.S. commercial airline trade group (Airlines for America, a/k/a A4A) nor the federal agency responsible for regulating aircraft and aviation safety in the United States, the FAA, sought reconsideration or appellate review.
The FCC continued moving forward with its process for the deployment of 5G broadband services in the 3.7–3.98 GHz portion of the C-band and issued several additional orders associated with its public auction of licenses for terrestrial broadband service uses in that portion of the C-band. The FCC commenced that auction in December 2020 and completed it in January 2021. Collectively, Verizon Wireless and AT&T Mobility spent more than $68 billion to acquire the majority of the C-band licenses that the FCC auctioned. These licenses included spectrum blocks in the 3.8–3.98 GHz portion of the C-band and spectrum blocks in the lowest (3.7–3.8 GHz) portion of the C-band. Additionally, to ensure that they could secure an early December 2021 nationwide launch date for their 5G terrestrial broadband services using their lower C-band (3.7–3.8 GHz) block licenses, Verizon Wireless and AT&T Mobility paid more than $10 billion in incentive payments to satellite companies to accelerate those satellite companies’ relocation of their technology and services from those lower C-band license blocks.
Remarkably, during the entire more-than-four-year period in which the FCC engaged in its notice of inquiry, rulemaking, and C-band auction and licensing processes, from August 2017 to the fall of 2021, the FAA was a nonparticipant in those processes. Then, on October 29, 2021, the Wall Street Journal reported that FAA officials had leaked plans to order flight delays, flight diversions, and flight cancellations in 46 of the country’s 50 largest metropolitan areas if the FCC did not halt Verizon Wireless’s and AT&T Mobility’s launch of their planned C-band broadband service operations, which were set to begin just over a month later.
The FAA issued a formal safety directive to the airline industry and aircraft owners and operators on November 2, 2021. AT&T Mobility and Verizon Wireless then voluntarily agreed to postpone the launch of their C-band broadband services for one month, until January 5, 2022, and agreed to additional restrictions regarding their turn-up of C-band services at numerous airport locations for an additional six months—restrictions that went beyond what the FCC had concluded were necessary to protect aviation safety.
Then, on December 30, 2021, less than one week before the already-delayed launch of Verizon Wireless’s and AT&T Mobility’s C-band services and almost 22 months after the FCC issued its C-Band Order, A4A, the trade group representing the U.S. commercial airline industry, filed with the FCC an emergency petition for stay of the C-Band Order, seeking to further delay the wireless industry’s deployment of 5G services using the C-band at 135 airport locations throughout the United States. On December 31, 2021, Verizon Wireless and AT&T Mobility, along with the wireless services provider trade group, CTIA (CTIA –The Wireless Association), filed with the FCC their opposition to A4A’s emergency stay petition. On January 2, 2022, AT&T Mobility and Verizon Wireless voluntarily agreed to more restrictions on turning up their C-band services in their licensed 3.7–3.8 GHz spectrum blocks for the following sixth months at numerous airports throughout the United States. Shortly thereafter, and without waiting for the FCC to act on its December 30 emergency stay petition, A4A withdrew that petition, but continued to dispute the sufficiency of the wireless industry’s temporary C-band usage restriction commitments and engaged in an extensive lobbying campaign with the executive and legislative branches of the federal government to enhance those voluntary restrictions and to further delay the wireless carriers’ turnup of their C-band-based 5G networks in numerous locations.
Although A4A’s emergency stay petition can be characterized as the legal equivalent of a Hail Mary football pass, subsequent events in the political sphere obviated the need for the FCC (and potentially the federal courts) to resolve the parties’ dispute via the legal process. For the next few weeks, the FCC, AT&T Mobility, Verizon Wireless, the FAA, and members of the Biden administration (principally the secretary of the U.S. Department of Transportation (DOT) and his staff) sought to resolve the impasse regarding the wireless carriers’ activation of their 5G services using their C-band licenses. From a technical standpoint, this impasse was due largely to the lack of real-world testing and, if necessary, repair or replacement by the aviation industry of radio altimeters that did not sufficiently filter out the electromagnetic signals generated by 5G services in the lower C-band spectrum blocks near U.S. airports, hundreds of megahertz below the frequency range in which those altimeters are licensed to operate.
To permit altimeter testing and remediation to occur, AT&T Mobility and Verizon Wireless ultimately agreed to delay the rollout of their C-band 5G terrestrial broadband services at approximately 50 U.S. airports until July 6, 2022. On January 18, 2022, the DOT announced an agreed framework among the interested parties and federal agencies to delay the wireless carriers’ 5G services activation at certain U.S. airport locations and resolve the potential altimeter interference issues. In late January 2022, as the parties began engaging in real-world testing and further exchanged data with each other, the FAA began clearing aircraft for normal operations at the affected airports and also began reducing the number of airports at which flight operations were restricted due to C-band-related aircraft safety concerns. However, as of late July 2022, that process was still ongoing.
Although the parties have made significant progress in resolving C-band-related aviation safety concerns, the aviation industry’s testing and repair programs for radio altimeters and the FAA’s clearance of those altimeters for unrestricted operations in airport landing zones where C-band-based 5G broadband services are provided are occurring at a slower pace than the parties originally anticipated. As a result, in June 2022, after additional discussions among the FCC, the FAA, and the aviation and communications industry parties, AT&T Mobility and Verizon Wireless agreed to delay full deployment of their broadband services using their C-band licenses at certain U.S. airports for an additional year, until July 5, 2023.
Due to the favorable propagation and channel reuse characteristics of the mid-band portions of the electromagnetic spectrum, the U.S. communications industry and U.S. policy makers began to focus their attention on those spectrum portions, including the C-band, for broadband services use more than five years ago. The C-band, in particular, has “desirable coverage, capacity, and propagation characteristics” that are crucial to 5G build-out, thus making it important that the band became more accessible to providers of 5G terrestrial broadband services. Not surprisingly, in early 2018, in section 605(b) of the MOBILE NOW Act, Congress directed the FCC to evaluate “the feasibility of allowing commercial wireless services, licensed or unlicensed, to use or share use of the frequencies between 3,700 megahertz and 4,200 megahertz”—that is, the C-band.
As noted above, even before Congress’s 2018 directive, the FCC had initiated, on August 3, 2017, a notice of inquiry regarding expanding flexible use of the mid-band spectrum. The FCC’s inquiry sought input on opportunities to increase access to spectrum bands between 3.7 GHz and 24 GHz, particularly for wireless broadband services. Specifically, the FCC requested comment on the use of three bands for such services: 3.7–4.2 GHz (the C-band), 5.925–6.425 GHz, and 6.425–7.125 GHz. For the C-band, the FCC asked for comment on how existing rules could be changed to promote flexible use, increase investment, and encourage intensive deployment for wireless broadband services.
Eight months later, in April 2018, the FCC established by public notice GN Docket No. 18-122, captioned “Expanding Flexible Use of the 3.7 GHz to 4.2 GHz Band.” This notice encouraged parties to submit filings in that docket regarding the opportunity for more intensive use of the C-band. A few months later, in July 2018, the FCC issued an order and notice of proposed rulemaking within the docket. The FCC explained that it hoped to make all or part of the C-band available for wireless broadband services, enabling the next generation of wireless services, including 5G. The FCC proposed allowing for more flexible and efficient use of that spectrum band by transitioning services currently operating within the entire band, principally satellite operations, to a narrower section of the band and to other frequency bands available for satellite service use. The FCC sought comment on its various proposals for the C-band—in particular for terrestrial broadband services use—and conducted its rulemaking proceeding over a 20-month period, until March of 2020. One of the many areas in which the FCC solicited comments was the technical restrictions needed to protect aeronautical radio navigation services that operate in the 4.2–4.4 GHz band.
During this period, A4A and several other aviation industry organizations filed comments with the FCC, raising concerns about C-band terrestrial wireless service signals causing potential interference with radio altimeters licensed to operate within the 4.2–4.4 GHz band. As noted above, radio altimeters are important systems that allow airplanes to gather information about their height above terrain and water. Many crucial life systems for airplanes rely on data from radio altimeters. Nonetheless, the federal agency primarily responsible for aviation safety, the FAA, did not file any comments or participate in the FCC’s NOI and rulemaking processes.
After almost three years of seeking comments through its NOI and rulemaking processes, in March 2020 the FCC issued the C-Band Order. The C-Band Order made a portion of the C-band, from 3.7 GHz – 3.98 GHz, available for 5G terrestrial broadband services. The order provided that the FCC would sell by auction later in 2020 and in 2021 licenses to operate such services within the C-band. The FCC stated that it intended to have a “robust transition schedule to ensure that a significant amount of spectrum is made available quickly for upcoming 5G deployments.” Specifically, the FCC adopted two accelerated relocation deadlines that provided incentives for space station (satellite) operators to meet early clearance deadlines for the band. The first accelerated timeline was clearing the 3.7–3.8 GHz portion of the band by December 5, 2021, followed by the remaining 3.8–3.98 GHz portion by December 5, 2023.
As part of the order, the FCC also adopted technical rules to prevent 5G C-band services from interfering with radio altimeters operating in the nearby 4.2–4.4 GHz band. These technical rules included limits on 5G antenna power and emissions in addition to spectral separation between services. Even though radio altimeters are not licensed to operate (and should not operate) outside of their designated spectral band, the FCC established that the upper spectral limit of the C-band licenses it would issue for flexible use—including for C-band terrestrial broadband services—would be 3.98 GHz. This meant that, for the initial planned December 2021 deployment of 5G broadband services using the lower C-band license blocks (3.7–3.8 GHz), there would be a separation of at least 400 megahertz between 5G C-band service frequencies and radio altimeter frequencies. Further, there would be at least a 220-megahertz separation after the upper portion of the C-band license blocks (3.8–3.98 GHz) was cleared for 5G broadband services use, which was scheduled to occur in December 2023. This 220-megahertz guard band was double the minimum requirement identified by both Boeing and the Aerospace Vehicle Systems Institute (AVSI) in their comments to the FCC during the FCC’s C-band rulemaking proceeding.
Additionally, the FCC’s order analyzed test results that AVSI provided in a report to the FCC after the comment and reply period. The AVSI report concluded that there could be concerns of radio altimeter interference from C-band terrestrial broadband service signals in some worst-case-scenario conditions where some radio altimeter receivers are susceptible to “performance degradation.” Following AVSI’s submission of its report, T-Mobile commissioned a study by Alion, an engineering firm, to review the test results underlying AVSI’s report. Alion raised several concerns about the report, particularly about the lack of actual testing results showing interference in any reasonable scenarios. AVSI, in subsequent filings, claimed that some radio altimeter receivers might be susceptible to performance issues and that further testing was required. The FCC determined that the AVSI report was not sufficient to warrant further safety protocols or prevent C-band flexible-use access. Specifically, the FCC stated that the report did not demonstrate that harmful interference to radio altimeters would likely occur under reasonable or even reasonably foreseeable scenarios.
In sum, the FCC concluded that the spectral separation of 220 megahertz that it created and the rules it imposed on C-band licensee power and emission limits were enough to offer “all due protection to services in the 4.2–4.4 GHz band.” At the same time, however, given that certain data from the AVSI report suggested that some radio altimeters might be operating outside of their designated frequency band, the FCC agreed that it would behoove the aviation industry to engage in further real-world testing and analysis of its radio altimeters, and encouraged AVSI (and the aviation industry generally) to continue with that testing and analysis. The FCC also stated that it expected the aviation industry to take account of the new C-band service environment (in particular, the licensing of spectrum blocks within the 3.7–3.98 GHz portion of the C-band for terrestrial broadband services use) and “take appropriate action if necessary to ensure protection” of radio altimeters.
In May 2020, following the FCC’s release of its C-Band Order and publication of its rules in the Federal Register, a group of aviation organizations, not including the A4A or the FAA, filed a petition for reconsideration of the FCC Order. The FCC did not rule on this petition and continued forward with its preparations for its C-band license auction, which it scheduled to begin in December 2020.
In November 2020, more than seven months after the FCC issued its C-Band Order and long after the deadline for reconsideration petitions had passed, the RTCA, another aviation industry group, filed a report with the FCC. This report asserted that, using the RTCA’s own self-created model and certain unspecified data from the AVSI report, there was a “major risk” of harmful radio altimeter interference from 5G service signals operating in the planned C-band license blocks. However, the RTCA did not file its report alongside any petition to the FCC or in any official rulemaking process pending at the FCC, nor did the RTCA make available at that time the underlying data upon which its reported “model” relied.
On December 1, 2020, the DOT and the FAA sent a letter to the National Telecommunications and Information Administration (NTIA), another federal agency with responsibility for, among other things, advising the U.S. President on telecommunications policy issues, serving as the federal executive branch’s representative on telecommunications policy matters, and managing the federal government’s use of electromagnetic spectrum. In this latter role, the NTIA is often referred to as having joint jurisdiction with the FCC over electromagnetic spectrum management, with the NTIA responsible for spectrum allocation and use by federal agencies and the FCC responsible for spectrum allocation and use by everyone else. The DOT/FAA letter requested that the NTIA interact with the FCC to defer the FCC’s further implementation of its flexible-use plans for the C-band, particularly with regard to the FCC’s planned auction of C-band licenses for terrestrial broadband service use, which the FCC had announced several months earlier would start on December 8, 2020. The DOT/FAA letter discussed the DOT/FAA’s concerns regarding interference with radio altimeters from 5G services deployment in the planned C-band license blocks and asserted that the “FCC’s path” in its multiple, multiyear proceedings to investigate and address issues associated with the more flexible and intensive use of the C-band, including for the provision of 5G broadband services, was “insufficient” to address the DOT/FAA’s stated concerns.
However, the NTIA did not submit this letter to the FCC docket, nor did the FAA or DOT engage with the FCC directly.
On December 8, 2020, the FCC began its auction of licenses to utilize the 3.7–3.98 GHz band for flexible use, including terrestrial broadband service use. The bidding closed in January 2021, with Verizon Wireless acquiring the largest number of licenses for $45.5 billion and AT&T Mobility acquiring the second-largest number for $23.4 billion.
After acquiring these licenses, AT&T Mobility and Verizon Wireless spent much of 2021 preparing to launch their 5G services within their lower C-band license blocks (3.7–3.8 GHz) in December 2021. They paid over $10 billion more to satellite companies to expedite the clearing of those lower C-band license blocks as part of the optional accelerated timeline that the FCC established in its C-Band Order. In addition, AT&T Mobility and Verizon Wireless spent billions of dollars more to lease tower space and purchase the necessary equipment for deployment of 5G services using those license blocks.
Despite the FCC’s extensive proceedings and processes intended to ensure a timely and smooth deployment of 5G broadband services within the C-band, and despite the wireless carriers’ sizable investments to ensure that they were ready to activate their 5G broadband services nationwide in December 2021 using their lower C-band license blocks, that deployment went nowhere near as planned. As noted above, on October 29, 2021, slightly more than a month before AT&T Mobility’s and Verizon Wireless’s scheduled nationwide activation of 5G broadband services using their lower C-band license blocks, the Wall Street Journal reported that FAA officials were planning to issue warnings to pilots and airlines about potential radio altimeter interference from the new 5G services.
The FAA claimed that if airplanes were unable to use their automated features because of interference, that situation “could lead to flight cancellations, delays, or diversions in 46 of the country’s largest metropolitan areas.” It was expected that the FAA would limit pilots’ use of those automated systems in order to avoid alleged potential interference. It was anticipated that such limits could result in entire regions or airports being shut down, according to a letter presented by aviation groups to the White House.
The FAA issued its formal safety alert on November 2, 2021. At that time, aircraft appeared to be operating safely—without experiencing radio altimeter interference from terrestrial broadband services using the C-band—in 40 other countries around the world, albeit those aircraft operations, and the provision of broadband services using the C-band, were subject to certain restrictions in certain airport landing zones.
What followed thereafter was several months of political and legal maneuvering by the affected parties and federal agencies and several halting attempts among those parties to find common ground: the FAA and aircraft manufacturers issued several additional radio altimeter safety alerts and directives, the wireless providers agreed to several short delays on their planned C-band 5G broadband services activation and to certain restrictions on their C-band 5G services activation near certain airports for an additional six months, the parties engaged in tense negotiations with each other and engaged in intensive lobbying of the legislative and executive branches of the federal government, and A4A filed with the FCC its Hail Mary emergency petition to stay—all with media headlines to match.
These activities were not without ramifications. The FAA’s and the aircraft manufacturers’ safety alerts led to numerous flight schedule disruptions during the traditionally heavy holiday travel season. The repeated safety alerts also stoked numerous media reports expressing concern about the safety of air travel and of the wireless carriers’ 5G services. To an outside observer, it was difficult to decipher how the parties arrived at their impasse. In addition, the process for resolving that impasse appeared, at times, chaotic.
Ultimately, however, cooler heads prevailed, and on January 18, 2022, the FAA, the FCC, government officials from the DOT, wireless service providers, and the aviation industry arrived at a tentative agreement for resolving their respective concerns. The parties’ agreement delayed the rollout of C-band 5G wireless services around certain U.S. airports until July 6, 2022, to allow the aviation industry to test, and repair or replace as necessary, any radio altimeters that did not properly filter out C-band 5G service signal transmissions occurring at frequencies below the 4.2–4.4 GHz band reserved for those altimeters, and to enable the FCC to clear those altimeters for flight operations in areas where C-band 5G services would be offered.
With the agreed C-band 5G service activation restrictions in place, the FAA in late January 2022 began clearing many commercial aircraft for landings at most U.S. airports. However, the FAA continued to report concerns about radio altimeters functioning incorrectly over the following few months.
In May 2022, the FAA met with U.S. aviation and communications industry officials to discuss its proposed solution to its concerns regarding such radio altimeter interference from C-band 5G signal transmissions. The FAA proposed that the airline industry repair or replace the affected radio altimeters and establish a timeline for doing so. The affected radio altimeters appear to involve a relatively small percentage of commercial aircraft, as the FAA already had cleared 90% of the United States’ commercial aircraft for use near 5G signals as of the time of its proposal.
In late June 2022, AT&T Mobility and Verizon Wireless agreed to further delay deployment of their C-band 5G wireless services around certain U.S. airports for an additional year, from July 6, 2022, to July 5, 2023. This delay is intended to allow aircraft owners further time to replace or repair any remaining malfunctioning altimeters that otherwise might be subject to potential interference from C-band 5G signal transmissions.
If the current schedule holds, AT&T Mobility and Verizon Wireless will be able to fully activate nationwide their 5G service offerings using their lower C-band license blocks in July 2023—approximately a year and a half later than originally scheduled and over two years after they acquired their licenses from the FCC to utilize the C-band for their 5G wireless broadband services. Because unrelenting consumer demand for 5G wireless services is what initiated the FCC’s C-band flexible-use proceedings and its sale of (and the wireless carriers’ significant investment in) C-band license blocks for terrestrial broadband services use, these service activation delays are costly not just to the wireless carriers but also to the public.
AT&T Mobility and Verizon Wireless incurred significant costs whose recovery will be delayed, if not eliminated altogether, by the restrictions visited by outside parties on their FCC-granted license rights. From a market standpoint, the devaluation of these carriers’ C-band investments by those after-the-fact license operating restrictions could dampen the demand for (and the resulting auction prices of) future spectrum auctions.
Similarly, insofar as those restrictions limit and delay unfettered consumer access to robust 5G services throughout the country, the American economy is not able to fully benefit from those 5G services, America’s global competitive stance suffers, and the American public is harmed. While other countries around the world have deployed 5G services without issue, delays in the U.S. wireless industry’s deployment of 5G services put the United States at risk of falling from its position as the global technological leader it historically has been.
It is readily apparent that, if there had been consistent communication and coordination between the FCC and the FAA throughout the FCC’s more-than-four-year notice of inquiry, rulemaking, auction, and license award processes, the U.S. wireless carriers’ deployment of 5G services pursuant to their FCC-issued C-band licenses would not have suffered from the dysfunction that the world witnessed between November 2021 and mid-January 2022.
During the FCC’s rulemaking proceeding where the FCC sought comment on issuing licenses for 5G services operating within the C-band, the FAA was absent. The FAA did not engage in that rulemaking process, nor did it file anything with the FCC after the FCC released its C-Band Order in March 2020. Similarly, following the C-Band Order, the airline industry failed to promptly institute a program to test for, and retrofit or replace, faulty radio altimeters as recommended by the FCC—likely because the FAA was not a proactive regulator in facilitating or mandating such a process. It was not until November 2, 2021, that the FAA issued its first airworthiness alert regarding potential radio altimeter interference from C-band 5G service signal transmissions, a little over a month before AT&T Mobility and Verizon Wireless were scheduled to activate their nationwide 5G service offerings using their lower C-band license blocks.
Although, at the time of this article’s writing in July 2022, the FAA has begun implementing its solution to the potential radio altimeter interference problem by demanding that the aviation industry retrofit or replace faulty radio altimeters, one has to wonder why the FAA didn’t undertake or mandate such a program far earlier. The FAA could have taken this remedial action when the FCC first undertook its rulemaking to authorize the licensing of C-band use for terrestrial broadband services in July 2018, or when the FCC recommended that the U.S. aviation industry undertake such a program when it issued its C-Band Order in March 2020.
As noted above, the FAA’s delay in addressing the radio altimeter interference issue was mirrored by the U.S. aviation industry’s failure to proactively undertake, on its own initiative, a program to test for, and retrofit, repair, or replace, any faulty radio altimeters that were unable to filter C-Band 5G signal transmissions. In economic terms, the aviation industry appeared to lack the incentive to proactively engage in testing and fixing faulty altimeters on its own. Instead, during the more-than-four-year time period when the FCC was conducting its notice of inquiry, rulemaking, and C-Band licensing processes, the aviation industry appeared to devote its efforts to trying to shift onto the communications industry the economic burden of addressing the radio altimeter issue.
An economist likely would say that this type of market failure or cost externalization is precisely one of the things the FAA was created to address. And while one can debate the economic merits of the parties’ respective positions, what is clear is that the FCC cannot regulate aviation safety, and the FAA cannot regulate the management, allocation, and use of electromagnetic spectrum.
In our view, it makes sense for the federal government to take steps to ensure that federal agencies communicate with each other on a regular basis, particularly federal agencies that regulate users of adjacent spectrum bands. It should establish a framework or guidelines for greater interagency communication when the interests of entities that one federal agency regulates are potentially affected by another federal agency’s activities, even if that framework or those guidelines merely encourage (rather than mandate) federal agencies to be proactive, both informally through appropriate ex parte procedures and formally through participation in another federal agency’s public proceedings.
In the case of electromagnetic spectrum allocation and management, such interagency communication can be critical to addressing and remediating on a timely basis the potential for conflict or interference between uses of adjacent spectrum bands by identifying and investigating up front any such conflicting use or interference concerns. This will only become a more critical exercise moving forward as technological changes and advancements in the communications industry become ever more frequent and as demand for access to additional portions of the electromagnetic spectrum, and the more intensive use of that spectrum, for communications services use grows.
Amid increasing demand for flexible spectrum use, disputes among spectrum users almost certainly will become more prevalent. In such an environment, interagency communication prior to the FCC’s issuance of spectrum licenses is especially important to address and resolve disputes between users. Once the FCC issues a license, it usually lacks the legal authority to retroactively change the terms and conditions of that license. This can make it particularly challenging to address issues of conflicting use or interference that were not resolved before the FCC issued the pertinent spectrum licenses. Furthermore, from an economic perspective, to promote efficient market outcomes, it is important that communications service providers can rely on the terms and conditions of their FCC-issued spectrum licenses. Injecting uncertainty into the licensees’ usage rights after the fact will negatively impact the spectrum and communications services markets, to the detriment of consumers.
A recent federal agency proceeding occurring after a spectrum-related dispute between the FCC and the U.S. Department of Defense (DoD) provides an example of the potential benefits of improved interagency communication. In May 2020, the DoD sought congressional relief regarding its objections to the terms upon which the FCC had granted a spectrum license to Ligado, a satellite communications company, to build a terrestrial wireless network. The FCC’s license allowed Ligado to use the L-band spectrum that is adjacent to the spectrum band used by GPS (Global Positioning System) services. The DoD claimed that part of its GPS services network would be compromised, affecting necessary GPS signals. The DoD had raised those concerns with the FCC during the FCC’s license proceeding, but the FCC had found those concerns unpersuasive. It appears, though, that the DoD and the FCC learned lessons from the ensuing controversy regarding the Ligado license grant, based on their conduct in a later FCC proceeding involving the issuance of licenses to nongovernmental parties for flexible or “shared” use of a different spectrum band, the 3.45–3.55 GHz band, which up to that time had been used solely by the DoD. In June 2021, prior to the FCC’s auction of licenses for the 3.45–3.55 GHz band, the FCC issued a joint public notice with the NTIA providing guidance for communications between federal government users and licensed nongovernment users regarding their respective uses of the band and establishing a formal process among those users for submitting spectrum use coordination requests.
In our view, continuous and robust communication among federal agencies is a critical and necessary tool in reducing the risk of spectrum-management dysfunction in the United States. Encouraging specific federal agencies with an interest at issue in a spectrum-management proceeding to actively engage in the FCC’s rulemaking process—and encouraging those agencies to require the spectrum users they regulate to proactively address spectrum-management issues that might impact those users’ operations—will reduce the prospect of such dysfunction. If the C-band controversy is any indication, interagency communication at the earliest stages of an FCC spectrum-management initiative, inquiry, or rulemaking can be essential to securing reasonable timelines for deployment of various spectrum service uses and to preventing economic harm not only to the parties involved but also to the American public.
