Tag: FAA

Is 5G Still Causing Issues for the FAA?

The ongoing debate over whether 5G causes issues with airplane equipment continues to be discussed and has reached another compromise. While cellular carriers want airlines to have to bring their equipment up-to-date, an aviation body argues that the current restrictions be made permanent.

The Problem

As satellite TV began to take a dive in the number of users, several frequencies were freed up for alternative use. The Federal Communications Commission (FCC) controls who gets to use what frequencies. They ultimately decided that these frequencies were suitable for 5G use so the rights to use them were auctioned off. Verizon and AT&T jumped on the chance to expand their 5G networks and acquired what is called 5G C-Band. 

Meanwhile, the Federal Aviation Administration (FAA), was apparently unaware of this auction. They discovered there was a risk of 5G C-band spectrum interfering with radio altimeters. This is the tool that essentially allows the airplane pilot to determine the altitude of the plane. It is always helpful to the pilot, but even more so in conditions of poor visibility. 

Surprisingly, the FAA had been talking about their concerns surrounding the potential risks of C-band interference since 2015. However, the agency didn’t directly communicate these to the FCC until it was too late.

Moving Forward

After several arguments between the two agencies, it’s still unclear as to whether the radio altimeters are truly at risk – there has been limited evidence. Still, delays were put in place to push out deployment, as well as restrictions at and around certain airports.  

An agreement was also made that gave the aviation industry until July 2023 to check their older aircraft. They would update radio altimeters as needed. Since that agreement, the deadline has again been pushed back, this time to February 2024. 

This past October, the aviation industry said that the temporary restrictions weren’t doing anyone any harm. They added that the costs of fixing the issue was expensive. So, it was argued that the power limitations be made permanent. The FAA rejected this. Instead, they decided to give airlines more time. Arstechnica reported the following: 

Today, the FAA proposed a deadline of February 1, 2024, to replace or retrofit faulty altimeters, which are used by airplanes to measure altitude.

Out of 7,993 airplanes on the US registry, the FAA said it “estimates that approximately 180 airplanes would require radio altimeter replacement and 820 airplanes would require the addition of radio altimeter filters to comply with the proposed modification requirement.” The total estimated cost of compliance is $26 million […]

“Some radio altimeters may already demonstrate tolerance to the 5G C-Band emissions without modification,” the FAA said. “Some may need to install filters between the radio altimeter and antenna to increase a radio altimeter’s tolerance. For others, the addition of a filter will not be sufficient to address interference susceptibility; therefore, the radio altimeter will need to be replaced with an upgraded radio altimeter.”

Another suggestion was also rejected by the FAA. The problem was only that affected radio altimeters reported a fault, but still functioned properly. So, they suggested that pilots simply be advised not to be concerned by the alerts at known problem spots. The FAA stated that this risked air crews becoming desensitized to system warnings, which “can lead to a catastrophic event.”

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What is the Aviation Industry Saying About 5G?

It’s been months since Verizon and AT&T got the approval to roll out their 5G C-Band networks to customers. This was done despite some concerns from airplane pilots and the FAA. Now the topic of whether or not 5G frequencies can cause interference with aircraft tools is back in the spotlight. 

The FAA monitored service for some time before coming to an agreement with the cellular carriers. In the initial rollout, they agreed that power levels would be limited and exclusion zones created around 50 key airports. 

Thankfully, no “catastrophic disruptions” have occurred in the time C-Band service has been in play. Still, several international airlines like Air India suspended their flights to major U.S. airports for the first 48 hours it was available. 

It’s probable that the agreed-upon exclusion zones helped mitigate some problems, but the proposed zones didn’t stop aviation officials from voicing concerns and pushing for more delays. The C-band rollout may have been proven to be a non-event, however this doesn’t mean there are not legitimate concerns. 

The FCC has been testing back and forth since 2020. This is around the time they had first proposed auctioning off the new spectrum. Their tests allegedly showed that the new C-band spectrum, which operates in the 3.7–3.98GHz range, was far enough away from the 4.2–4.4GHz frequencies used by radar altimeters. FCC’s experts said this 0.22GHz (220MHz) gap would be more than enough to avoid interference.

The FAA disagreed with these findings and referenced a 2020 research paper by the Radio Technical Commission for Aeronautics (RTCA). The RTCA is an independent technology standards group representing the air transportation industry. The study showed that 5G telecommunications in the C-band spectrum could cause “harmful interference” to radar altimeters due to spurious emissions and “bandwidth pollution.”

The study conceded that the frequencies were far enough apart from each other that problems shouldn’t occur. However, the issue was that increased 5G usage was likely to result in a strong enough concentration of signals that they could “bleed through” into neighboring frequency bands.

Such interference could cause the radar altimeters in most commercial aircraft to show incorrect readings. This is why the FAA’s list of 5G-excluded airports includes many smaller regional fields that are prone to heavy fog and extended periods of low visibility.

According to a recent report by IEEE Spectrum, complaints about altimeter failures rose significantly following the January 19 deployment of the new C-band spectrum. A few instances occurred during multiple flights over Tennessee. Pilots experienced altimeter errors that made it impossible to maintain assigned altitude.” Another pilot reported having lost its autopilot completely and another who received errors upon landing at an airport. 

Specifically, 93 reports related to radar altimeter problems were filed between January and May this year. “January alone saw almost twice as many complaints of malfunctioning altimeters as the previous five years combined,” an analysis from IEEE Spectrum noted. 

The FAA told IEEE Spectrum that it has received around 550 submissions since January, although it’s only investigated about half of them so far. The agency couldn’t rule out 5G interference in about 80 reported incidents. However, it was quick to add that none of those incidents that could have been caused by 5G had any impact on systems related to aircraft safety. Regardless, the increasing number of reports has pilots and others within the aviation community spooked. 

Fortunately, the National Telecommunications and Information Administration (NTIA), which advises the President on telecommunications and information policy issues, has been working with the Defense Department, mobile carriers, and the aviation industry to continue studying the impact of the new 5G frequencies.

The NTIA reports that there was a “low level of unwanted 5G emissions” in the frequencies used by so-called radar altimeters. To be clear, the report isn’t saying that aircraft instruments are immune from 5G interference. Instead, it confirms that the precautions exercised by the aviation industry and the mobile network operators have been helping.

That being said, we won’t be seeing Verizon’s Ultra Wideband or AT&T’s 5G Plus network at major airports anytime soon. Since these higher-tier 5G services mostly use the C-band spectrum, the carriers have to wait until the FAA has given them approval to proceed. That should only happen once all of the potentially impacted radar altimeters have been patched or replaced.

The FAA notes that radio-altimeter manufacturers have been working swiftly to develop and test filters and installation kits for aircrafts. The work will mostly be completed by next July.

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When Will the FAA Allow 5G Enhancements Around Airports?

It has been months since Verizon and AT&T agreed to temporarily limit their 5G expansion plans due to concerns about how the new wireless standard could interfere with aircraft tools. All this time, the Federal Aviation Administration has been working with the cellular carriers to find a solution to using 5G safely at and around airports. They are currently in a “phased approach” to the 5G launch.

On Friday, they all reached an agreement that will allow the carriers to expand their 5G service around some airports while continuing to temporarily hold off elsewhere. This will allow companies time to retrofit their aircrafts with equipment that is less susceptible to 5G interference. Part of the plan is to have those with the most vulnerable (to 5G interference) regional aircrafts be required to retrofit the planes with radio frequency filters by the end of the year.

As both the FAA and carriers work together they have also identified certain airports near which the telecommunications companies will be able to enhance their service with the least risk of causing disruptions to flight schedules.

Per the press release, acting FAA Administrator Billy Nolen said, “We believe we have identified a path that will continue to enable aviation and 5G C-band wireless to safely co-exist.” 

The latest release noted that AT&T and Verizon had previously agreed to limit the service until July 5 and have since offered “to continue with some level of voluntary mitigations for another year.” When that time is up, it’s expected that airlines and other operators will be done with the work required to enhance their aircraft with the appropriate equipment. This would then allow the wireless companies “to operate their networks in urban areas with minimal restrictions.” 

“Today’s announcement identifies a path forward that will enable Verizon to make full use of our C-Band spectrum for 5G around airports on an accelerated and defined schedule,” Verizon Chief Administrative Officer Craig Silliman said in the Friday press release. “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.”

An AT&T spokesperson also commented, stating that the company is moving toward seeing all voluntary restrictions lapse by next summer.

“Through close coordination with the FAA over the last several months, we have developed a more tailored approach to controlling signal strength around runways that allows us to activate more towers and increase signal strength,” the AT&T spokesperson said. “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.”

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Can 5G Interfere with Military Radars?

You may remember months ago when a dispute between airlines and telecommunications companies became a hot topic. That dispute was of course about the risk 5G C-Band could have on aircraft landing tools. As the U.S. looks to deploy more spectrum for faster wireless communications, this topic may soon be back in the spotlight.

The National Telecommunications and Information Administration (NTIA) is in place to mediate disputes related to spectrum allocation. Earlier this year, they simply stood by while tensions grew with other agencies and the U.S. aviation system was essentially at a standstill. 

“The process fell apart,” Tim Farrar, a technology consultant who leads his own firm, Telecom Media Finance Associates Inc., said. “Nobody talked to anybody.”

The FAA’s mother agency, the Transportation Department, in late 2020 circulated a letter seeking a delay in moves to allow the new 5G service. The NTIA didn’t act.

“We fully expected the NTIA to send our comments to the FCC,” Diana Furchtgott-Roth, the senior Transportation Department official responsible for radio spectrum issues at the time, said in an interview.

Adam Candeub, the NTIA acting administrator at the time, said the FAA’s concerns weren’t forwarded because NTIA experts had found no substance to the concerns.

In coming months, the agency will serve as referee as commercial operators seek access to frequencies that are now used by Navy and Army radars. These radars track targets or artillery fire and launch points for missiles.

Officials will be working with the Pentagon to determine which frequencies can be relinquished, and which can be shared with commercial operators, possibly with restrictions on signal power or hours of use. A decision is expected by next year.

“I think part of the bigger lessons learned that I’ve pulled out of the 5G effort is talk early and then talk early and talk some again,” Michael Weiler, group manager of the Federal Aviation Administration’s Spectrum Engineering Services division, said Wednesday at a webinar sponsored by the nonprofit government advisory group RTCA Inc.

The NTIA hasn’t been the most stable recently due to cycling through five leaders in the final 20 months of Trump’s presidency. In an effort to improve the agency’s performance, the Biden administration pledged to assist. In February, the agency joined the Federal Communications Commission (FCC) in a pact to improve coordination — and avoid confrontations such as the dispute with the FAA.

The 5G experience shows the need for cooperation before controversy arises, said Steve Dickson, the former FAA administrator who left the agency at the end of March.

“We’ve just got to work together to make sure that we have smoother roll-outs going forward,” Dickson added. “This won’t be the last spectrum issue that we encounter.”

Alan Davidson, the Biden administration’s NTIA leader, and FCC Chairwoman Jessica Rosenworcel have already begun work on this objective. March 29 was the first of their meetings, and they will likely have one a month from this point. In a recent statement, they said they would work together on a task that requires “clear communication, open doors, thoughtful listening, and mutual respect.”

In addition to their improvements, the NTIA and FCC are talking about forming a national spectrum strategy in effort to avoid these issues. They will examine stricter standards for receivers that would focus devices such as aircraft navigation systems on a tighter band and reduce conflicts.

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How Long Will It Take to Resolve the Issues Surrounding C-Band 5G

Just when we thought we had heard about the last delay with C-Band 5G, the FAA now says it could take another year before areas around airports will benefit from C-Band’s speed upgrades. 

The subject was a hot topic that was discussed at a hearing held Thursday by the House Transportation and Infrastructure Committee. During this hearing, lawmakers voiced frustration with the Federal Aviation Administration and the Federal Communications Commission, and asked why the standoff was not resolved earlier.

The aviation industry and FAA had warned that 5G interference could impact sensitive airplane electronics such as radio altimeters, which gauge the height of an aircraft above terrain immediately below it and are used in low visibility landings. Steve Dickson, the FAA Administrator, testified that federal agencies need to improve their coordination in such matters because there will be additional spectrum issues in the future.

“The process did not serve anyone well,” Dickson said. “It did not serve the aviation community well, certainly the FAA, and it also did not serve the telecommunications industry well. And we certainly need to do better as a country.”

“5G and aviation can safely coexist,” Dickson told the panel. He then took the next two hours to explain how much work it’s going to take before that safe coexistence can occur.

With regards to the steps taken by AT&T and Verizon thus far, Dickson said he’s satisfied this will help to avoid possible interference on their initial C-Band 5G service. The frequency in question ranges from 3.7 to 3.8GHz and radio altimeters – the devices that the service can interfere with – operate from 4.2 to 4.4GHz. 

AT&T and Verizon have already pushed back their C-Band launches twice and agreed not to deploy C-Band in buffer zones around airports created by the FAA. This began in December, but rollouts did not start until January 19th. 

Intensive testing has been performed by the FAA and they continue to do so. They have already cleared 20 altimeter models and certified 90 percent of the US commercial fleet as safe to operate in low-visibility conditions that would require relying on radio altimeters.

“All parties are working together very effectively at this point,” Dickson said, crediting wireless carriers for providing the government with more detailed information about cell-site location, power strength, and signal shape.

What about smaller aircrafts? Regional and business jets, helicopters and other “general aviation” aircraft with altimeters are still uncertified against C-Band interference.

Dickson noted that discussions with altimeter manufacturers are showing some promise. They’ve suggested some of those altimeters could be fixed with radio-frequency filters. Ultimately, the FAA needs to write altimeter performance standards for C-Band resistance, which he said will probably take a year before manufacturers can design new units.

With that being said, it means the originally planned 6 month delay is going to run much longer. The good news is that the testing everyone is doing is already helping the FAA to chip away at the buffer zones, making them just a little smaller as time goes on. 

Almost every member of Congress at the hearing had the same questions we’ve had – how could an interagency coordination process meant to avoid last-minute conflicts could have gone so wrong? 

Dickson’s response put partial blame on the wireless carriers, saying that they did not provide sufficiently detailed technical data until December. Some committee members, meanwhile, blamed extended leadership vacancies during most of the Trump administration at the Commerce Department’s National Telecommunications and Information Administration (NTIA), the agency that’s supposed to help coordinate these efforts. 

A failure to communicate indeed, which still continues it seems since the FCC, which ran the C-Band auction, did not participate in the hearing. 

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Verizon plans to turn on around 2,000 5G towers this month

According to sources from Reuters, Verizon Communications Inc plans to turn on around 2,000 additional towers this month. This is all part of its next phase of C-Band 5G deployment after the United States Federal Aviation Administration (FAA) agreed with both Verizon and AT&T that it was now safe to turn on more 5G towers. Of course, this only comes after many months and a couple delays because of the aircraft safety concerns with the C-Band spectrum.

Verizon agreed in January to not deploy about 500 towers near airports. Since then, about 5,100 towers were turned on last month. Now they will be able to turn on about another 2,000 in February, the sources said, adding that the total could rise as aviation buffer zones are refined.

Verizon also says they are still on track to meet their promise of 100 million users covered by March 31. As of Tuesday, it had already met the 100 million goal and intended “to exceed that goal.”

The carrier, and the FAA, declined to comment on the number of new towers being activated, but Verizon said it remains committed to “very productive discussions with the FAA and others”.

On Friday, the FAA reported new data had allowed it to “more precisely map the size and shape of the areas around airports where 5G signals are mitigated, shrinking the areas where wireless operators are deferring their antenna activations.”

Based on the new revised exclusion zones, Verizon is expected to be able to deploy about 14% of the 500 towers held up in January, or around 70 towers, the source added.

The FAA is working on a subsequent version of the buffer zones that will allow Verizon to turn on additional towers.

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FAA Allows AT&T, Verizon to Turn on More 5G Towers

Announced Friday, The U.S. Federal Aviation Administration (FAA) said it has agreed that Verizon Wireless and AT&T can safely turn on additional towers for their C-Band 5G deployment.

“Through continued technical collaboration, the FAA, Verizon, and AT&T have agreed on steps that will enable more aircraft to safely use key airports while also enabling more towers to deploy 5G service,” the FAA said in a statement. The FAA said more precise data about the exact location of wireless transmitters allowed it “to determine that it is possible to safely and more precisely map the size and shape of the areas around airports where 5G signals are mitigated, shrinking the areas where wireless operators are deferring their antenna activations.”

The FAA had imposed flight restrictions as a result of new 5G service possibly causing interference with aircraft altimeter tools (something pilots use to help land in inclement weather). Verizon and AT&T originally disputed the FAA’s warnings, but they twice agreed to delay launching new 5G. They also temporarily delayed it around 50 US airports even as they began offering the service in many U.S. cities on Jan. 19.

The FAA said that it took steps to reach this agreement after receiving details from the telecommunications companies about the location of wireless transmitters. The data helped it to better map areas around airports where the new high-speed 5G service won’t hinder the ability of planes to land during poor weather.

Now that the dispute has come to a head, the FAA has cleared most types of airline planes to operate around 5G signals, saying that their height-measuring devices, radio altimeters, are safe from radio interference.

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FAA Releases List of Airports with 5G Buffer Zones

The FAA and cellular carriers, AT&T and Verizon, agreed to minimize their new 5G coverage using the C-Band frequency. A statement was recently released by the FAA that buffer zones have been set up for the coming 5G C-Band deployment. These airport locations will have temporary zones placed to protect them from potential interference from the 5G signals – aviation experts have found possible risks related to aircraft tools.

According to the FAA, 5G services on the C-Band are still set to launch on Jan. 19. They will continue the rollout with these limitations in place for at least 6 months. Only time will tell if more delays are to be seen, but thankfully 5G testing in other countries, using the same frequencies in the C-Band, have not reported any interference issues.

There are currently 50 airports on the FAA’s buffer zone list. The airports were selected based on traffic volume, the number of low-visibility days, and geographic location. There was also input from people in the aviation community. The list includes airports of any size, some of which are documented below:

  1. Austin-Bergstrom International Airport
  2. Charlotte Douglas International Airport
  3. Chicago Midway
  4. Chicago O’Hare
  5. Dallas-Fort Worth International Airport
  6. Dallas Love Field
  7. Detroit Metropolitan Airport
  8. George Bush Intercontinental Airport (Houston, Texas)
  9. John F. Kennedy International Airport
  10. John Wayne Airport (Orange County, Calif.)
  11. LaGuardia Airport
  12. Los Angeles International Airport
  13. Miami International Airport
  14. Minneapolis–Saint Paul International Airport
  15. Newark Liberty International Airport
  16. Philadelphia International Airport
  17. Phoenix Sky Harbor International Airport
  18. San Francisco International Airport
  19. Norman Y. Mineta San Jose International Airport
  20. Seattle–Tacoma International Airport
  21. William P. Hobby Airport (Houston, Texas)

Over the next 6 months, FAA officials say they will continue to work with airline companies and manufacturers to verify how the radar altimeters (the tools which may be affected by interference) will perform in this new environment.

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Verizon and AT&T agree to additional C-Band delay

In early 2021, an FCC auction sold Verizon and AT&T rights to use “C-band” frequencies at a price of almost $70 billion. The carriers are certainly eager to roll out the service, not only to catch up to T-Mobile, but because the new spectrum will provide in-between performance over much wider coverage areas. T-Mobile is unaffected currently since it uses mid-band spectrum that isn’t in the C-band.

Since our update on C-Band delays yesterday, we understand that both carriers have agreed to the additional 2 week delay.

Verizon:

“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 network.”

AT&T:

“At Secretary Buttigieg’s request, we have voluntarily agreed to one additional two-week delay of our deployment of C-Band 5G services. 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 also learned that FAA Communications deputy assistant administrator Jeannie Shiffer provided a statement to The Verge saying, “Safety is the core of our mission and this guides all of our decisions. The FAA thanks AT&T and Verizon for agreeing to a voluntary delay and for their proposed mitigations. We look forward to using the additional time and space to reduce flight disruptions associated with this 5G deployment.”

Per the agreement, she adds that companies will use mitigations similar to those already in place in European countries. The deal will see those mitigations put in place around 50 airports for six months. The FAA says, “While U.S. standards and operating environments are unique, we believe this could substantially reduce the disruptions to air operations.”

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AT&T and Verizon reject U.S. request to delay 5G deployment

January 5th is fast approaching. This is the date in which carriers, AT&T and Verizon, were instructed to delay 5G rollout on the C-Band spectrum. If you’re not already aware, this is because of possible interference on these frequencies with aircraft safety tools. 

U.S. Transportation Secretary Pete Buttigieg and Federal Aviation Administration chief Steve Dickson sent out a request to delay 5G rollout, again, this time for another 2 weeks. This request was sent to the CEOs from AT&T and Verizon, who have responded in a joint letter as of yesterday. 

“Commercial C-band service would begin as planned in January with certain exceptions around priority airports,” states the request. 

The request comes two days after the trade group Airlines for America (A4A) asked the Federal Communications Commission (FCC) to stop the wireless industry from turning on C-band spectrum for commercial deployment on January 5. The airline group has said it may go to court today if the FCC does not act.

Per the FAA, they need the additional two weeks to “identify the priority airports.” The FAA also needs the extra time to approve certain high-performing radio altimeters to operate at those airports.

“This will allow for 5G C-band to deploy around these priority airports on a rolling basis, such that C-Band planned locations will be activated by the end of March 2022, barring unforeseen technical challenges or new safety concerns,” said the request.

The previous delay request was to limit coverage around airports for at least 6 months. The carriers agreed to this, but in their response, denied any broader limitation on using C-Band spectrum. They said the Transportation Department proposal would be “an irresponsible abdication of the operating control required to deploy world-class and globally competitive communications networks.”

AT&T and Verizon also proposed a new exclusion zone in their response. The exclusion zone is currently in use in France, the carriers said, “with slight adaption” reflecting “modest technical differences in how C-band is being deployed.” Per FAA officials, France uses spectrum for 5G that sits further away from spectrum used for radio altimeters and uses lower power levels for 5G than those authorized in the United States.

“The laws of physics are the same in the United States and France,” the CEOs wrote. “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.” 

Verizon states they will only use spectrum in the same range as used in France, but they plan to use additional spectrum in the coming years. The larger U.S. exclusion zone around U.S. airports is “to make up for the slight difference in power levels between the two nations,” Verizon added. 

Regarding the new exclusion zones, government and industry officials say it is not as large as what the FAA had suggested earlier.

The FAA and Buttigieg on Friday proposed identifying priority airports “where a buffer zone would permit aviation operations to continue safely while the FAA completes its assessments of the interference potential.”

An FCC spokesperson said Sunday the agency is “optimistic that by working together we can both advance the wireless economy and ensure aviation safety.”

Wireless industry group CTIA said 5G is safe and spectrum is being used in about 40 other countries.

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