Want to read Slashdot from your mobile device? Point it at m.slashdot.org and keep reading!

 



Forgot your password?
typodupeerror
×
Government Transportation

America's FAA Issues Warning Over Concerns 5G Might Interfere with Aviation Altimeters (avweb.com) 79

Long-time Slashdot reader SonicSpike quotes the aviation news site AVweb's report on a "Special Airworthiness Information Bulletin" and "Airworthiness Directive" being issued by America's aircraft-regulating Federal Aviation Administration "concerning the rollout of 5G cellular phone service in 46 major metropolitan areas of the U.S." (reportedly happening on December 5th). The actions are expected to limit the use of automated systems on aircraft that rely on radar altimeters (also called radio altimeters) and it's possible that flight delays and cancellations will result. Reuters also quoted a letter from FAA Deputy Administrator Bradley Mims that says the agency shares "the deep concern about the potential impact to aviation safety resulting from interference to radar altimeter performance from 5G network operations in the C band."

In an auction of radio spectrum last year, the major telecoms paid a total of $78 billion in an FCC auction to get access to a thin slice of the finite range of available radio frequencies to carry 5G signals. Those signals will be in the 3.7 to 3.98 GHz part of the so-called C-Band, which is apparently the sweet spot for carrying the data-heavy 5G signals. Radar altimeters operate in the 4.2-4.4 GHz frequency range (their sweet spot) and the fear is that the nearby powerful cell signals will cause interference for the avionics. The FCC approved the use of the spectrum for 5G saying "well-designed [radio altimeter] equipment should not ordinarily receive any significant interference (let alone harmful interference)."

But aviation groups say the risk for thousands of aircraft is real and the FAA seems to agree.

This discussion has been archived. No new comments can be posted.

America's FAA Issues Warning Over Concerns 5G Might Interfere with Aviation Altimeters

Comments Filter:
  • So... (Score:5, Interesting)

    by kurkosdr ( 2378710 ) on Sunday November 07, 2021 @03:15PM (#61966419)
    So far, 5G (the non-mmWave variant) has cost us 10 UHF muxes for terrestrial television (which is especially painfully here in Europe where the DVB standard doesn't make use any of the VHF bands, it's why we have ~5Mbps FullHD channels) and interference in aviation altimeters.

    It better deliver on its promises of connecting cars and emergency respondents everywhere.
    • by Vihai ( 668734 )

      Amen to this! EM spectrum to transport TV is a terrible waste of resources.

      • Re:So... (Score:5, Insightful)

        by kurkosdr ( 2378710 ) on Sunday November 07, 2021 @04:24PM (#61966569)
        I disagree. I like the idea of having access to streaming video and audio without having to subscribe to anything, or be reliant on any ISP, or be subject to data caps. Remember, the spectrum is supposedly for the public good, so I think it's great there is some service which can be accessed without agreeing to someone's terms-of-service.
        • Re:So... (Score:4, Insightful)

          by kurkosdr ( 2378710 ) on Sunday November 07, 2021 @04:31PM (#61966585)
          For example, there is a resurgence in demand for TV antenna installations in the US because people want to ditch cable (and related fees and crap customer service) while still having access to sports content (which is available for free on terrestrial TV). Terrestrial TV is one of the best tools in a cord-cutter's toolset.
        • Remember, the spectrum is supposedly for the public good, so I think it's great there is some service which can be accessed without agreeing to someone's terms-of-service.

          a) you have access to this content on the very frequencies you complain about (please spare us the altruistic posturing, we all know you have a phone with data).
          b) you are agreeing to someone's terms-of-service. There's basically no DVB receiver that comes without one, you probably just don't remember it back on the first day you turned it on.
          c) You presented the solution in your post. TV should move to VHF and be rate limited. FullHD via a service very few people use should not block far more useful use of

          • by sxpert ( 139117 )

            also, anything that is currently free to air on the airwaves should be required to be available over the internet

          • Sorry, agreeing to Terms of Service when buying a TV?

            Uh, no, not in Australia, free to air TV and the TV sets themselves have NO agreement required. You plug TV into power and aerial, turn it on, tell it to tune itself to the dozens of channels, then watch hdtv for free.

            I have purchased a number of tvs over the years, none have had any sort of Terms of Service agreement.

            I also note that TV channels in Australia are VHF or UHF.

            • Uh, no, not in Australia

              I see you've never bought a TV in Australia. My TV here in Europe which very much has an Australian plug on it certainly came with terms of service.

              • Well, every TV I've ever bought has been in Australia, where I live.

                So... no?

                Or perhaps it's in the half ream of paper that often comes with TVs that I tend to glance at for the warranty and instructions and then file away? Certainly nothing that I have to agree to, nor can I - it's a tv not a computer.

                I'll point out that I've never bought a smart TV, having no use for such a daft thing, my 65" is plugged into a A/V receiver along with a HTPC, settop box and Xbox One S, so it's plenty 'smart' and won't stop

                • So... no?

                  The only thing "no" about your comment is you can't remember what happened when you first turned it on many years ago. Australian TVs have a ToS agreement. You likely were mashing the ok button trying to get to the channel select screen.

                  • Hmm.

                    Well, I own a Hisense, Soniq and JVC tv and just went to their websites and they have no "EULA" or "Terms of Service" found using their internal search functions nor does a Google search find any such thing for these tvs.

                    Please, supply links to such?

                    I mean, it's certainly plausible that I could have mashed the ok button to get to channel search, but something as important as Terms of Service would be on manufacturers websites and easily found. That is, specifically on websites ending in .au, since I'm r

                    • Only have Toshiba, and Samsung. The Terms of Service are on the screen when you first turn it on, not on the website.

                      Sidenote: Soniq is still around?

                    • Oh. I see no links to your claimed Terms of Service?

                      How does a non-smart TV record acceptance of these alleged Terms of Service anyway? They have no internet connection, no way to communicate acceptance or denial of such terms.

                      While I don't have those brands of TVs, and you don't have my brands, I'm thinking that we are at a impasse, though I'm holding all the cards since you are unable to provide any evidence backing up your claim to 'Terms of Service' existing at all. Not even any links to people discussi

          • And you don't understand that the major advantage of terrestrial television is that once it's out there, it's out there and you can receive it. They can't block you in any discriminatory manner (for example for not accepting some TOS), they can't impose DRM on you, they can't throttle you, and they can't randomly change the format to take out your receiver and force you to buy a new one like for example YouTube did with their API format (in terrestrial television, any format changes need regulatory approval
        • by PPH ( 736903 )

          I like the idea of having access to streaming video and audio without having to subscribe to anything

          I've had that for years. OTA broadcast TV.

      • by tlhIngan ( 30335 )

        Amen to this! EM spectrum to transport TV is a terrible waste of resources.

        No, using UHF and VHF for TV is a waste of resources. A TV channel is 5 or 6 MHz in width, and when you're talking about the part below 1GHz (UHF and lower), that's a TON of bandwidth for the area, especially given a lot of it is special. Under 30MHz is great for worldwide radio (the HF bands), while the VHF and UHF are split into many uses because the signal can penetrate walls easily enough and thus useful for commercial, military,

    • by AmiMoJo ( 196126 )

      I don't know how terrestrial broadcasters expect to compete anymore. I guess maybe they have a lot of legacy viewers but personally I find the quality of "full HD" channels to be unwatchable. It's that bad.

    • This is just another way, as an excuse to stop any and all 5G mobile use on planes.

  • America's FAA? (Score:5, Insightful)

    by RightwingNutjob ( 1302813 ) on Sunday November 07, 2021 @03:19PM (#61966429)

    As opposed to Saudi Arabia's FAA?

    Legally, it's not even "America's" FAA, it's

    U.S. DEPARTMENT OF TRANSPORTATION
    Federal Aviation Administration

    (See www.faa.gov)

    And every federal office and agency is "United States blah blah blah" while very few official names have "America" in them at all.

    • by Anonymous Coward

      People in other countries don't have the acronyms of American government agencies memorized and they read /.

    • There are at least two other uses of "FAA" in an aviation sense which are not related to the Federal Aviation Administration.

      This is a website with an international audience, expecting everyone to instantly know everything about every US based authority, government body or agency is simply ludicrous or indeed shows considerable bias or arrogance.

    • Yeah that was not the original title I submitted with the article, mods changed it apparently.

      • Yeah that was not the original title I submitted with the article, mods changed it apparently.

        Damn. Well, it increased engagement, fwiw, so a win in their eyes. I estimate at least 10% of comments on /. are based on pedantry. (I low-balled the percentage on purpose to elicit engagement from said pederasts. That's the right word, isn't it?)

  • See, the anti-Gatesers were right!

  • 5G Might Interfere with Aviation Altimeters

    Just don't *also* vaccinate those altimeters against COVID. Whew, disaster averted.

  • by gweihir ( 88907 ) on Sunday November 07, 2021 @03:44PM (#61966485)

    Fascinating.

  • by TheNameOfNick ( 7286618 ) on Sunday November 07, 2021 @03:54PM (#61966501)

    Look ma, no filter!

    • by Vihai ( 668734 )

      Yeah... such separation is super wide and can be filtered with ease. If a radioaltimeter is so susceptible to that kind of interference I would question the qualification standards.

  • The FCC approved the use of the spectrum for 5G saying "well-designed [radio altimeter] equipment should not ordinarily receive any significant interference (let alone harmful interference)."

    So flip the "well designed" burden onto the newcomer, have rigorous testing and approval to make sure 5G equipment stays in the 3.7 to 3.98 GHz range and does not interfere with the altimeter range of 4.2 to 4.4 GHz.

    Of course this is not to say new altimeters that are introduced shouldn't try to make themselves less vulnerable to wayward 5G signals. Its just that we should be focusing burdens on new equipment not legacy equipment.

    • So flip the "well designed" burden onto the newcomer, have rigorous testing and approval to make sure 5G equipment stays in the 3.7 to 3.98 GHz range and does not interfere with the altimeter range of 4.2 to 4.4 GHz. Of course this is not to say new altimeters that are introduced shouldn't try to make themselves less vulnerable to wayward 5G signals. Its just that we should be focusing burdens on new equipment not legacy equipment.

      No, this isn't how the design and approval of radio equipment works. The fault depends on how the interference is happening.

      Option 1 - Out of band emissions
      If the 5G equipment is producing any significant amount of energy inside the radar altimeters 4.2 to 4.4 GHz range then, yes, it is at fault and must be switched off until it is fixed.

      Option 2 - Insufficient receiver selectivity
      If however, the radar altimeters are adversely affected by energy arriving in the 3.7 to 3.98 GHz range then they are a

      • by drnb ( 2434720 )
        As I said, make sure new altimeters are focused on the proper band. However old altimeters that were fully compliant with old standards should be accommodated, and that the burden should be on the new 5G equipment. As an engineer I understand the preference for doing things the right way from the beginning, but reality is that we are often overridden. Hence my willingness to make accommodations for legacy equipment that is compliant with legacy regulations.
        • How, pray tell, are equipment manufacturers who produce equipment which 100% stays within its assigned license band supposed to "fix" this issue?

          Turn it off entirely? Not use the spectrum at all?

          Because thats the only solution, if fixing the old altimeters is not an option in your world - theres nothing properly operating equipment can do to prevent interference with another unintended device if that "interference" is actually just the normal operation of the equipment within the band its licensed for.

          If w

          • by drnb ( 2434720 )
            As "5G" paid for spectrum, they can pay for altimeter upgrades for legacy systems that are in compliance with legacy standards.
            • They were not fit for function, they were not in compliance with reasonable standards of engineering, they worked by accident.

              • by drnb ( 2434720 )

                They were not fit for function, they were not in compliance with reasonable standards of engineering, they worked by accident.

                You mean ideal standards of engineering. Reasonable standards of engineering often involve compromises, that's kind of a major function of engineering, get something to work within these parameters. A parameter might be cost. In any case, the relevant metric is what were the regulator standards. Today, if we are saying the nearest user is 200 MHz away, when the equipment was made was the nearest user defined to be 500 MHz away? 200 or 500 is just an illustration, I am not implying they are/were actual stand

                • by sxpert ( 139117 )

                  considering the price said radio altimeters are sold for, they are expected to have exceptionnal filtering caracteristics on their front-end.
                  if not, you've been ripped-off

                • You mean ideal standards of engineering. Reasonable standards of engineering often involve compromises

                  Air safety does not involve compromises caused by equipment that has such poor RF selectivity that a 5% frequency difference is not excluded more or less completely. That kind of crap could be brought down by almost anything.

                  We don't apply the standards relevant to Roman bridge builders to air safety - we have proper standards for that. And the planes are supposed to be tested for compliance to said sta

                  • by drnb ( 2434720 )

                    You mean ideal standards of engineering. Reasonable standards of engineering often involve compromises

                    Air safety does not involve compromises caused by equipment that has such poor RF selectivity that a 5% frequency difference is not excluded more or less completely.

                    Again, I offered a hypothetical. Say in the past the nearest neighbor was 500MHz away, and the equipment had a 250MHz safety margin around its frequencies. That could reasonably be determined safe at the time. However if one day in the future the FCC moves a neighbor to only 210 Mhz away, now we have a problem. Again, this is just for illustration purposes. How what was reasonable yesterday may no longer be reasonable today.

                    That kind of crap could be brought down by almost anything.

                    Not really, Aircraft typically have both barometric and radio altimeters, they have

            • Why should they have to? Its the FCCs problem, they can pay for it out of the license fees taken.

        • Hence my willingness to make accommodations for legacy equipment that is compliant with legacy regulations.

          Ah, here you have put your finger on the key questions. What were the "legacy regulations"? How - if at all - do they differ from current regulations? Do the older altimeters actually comply with these "legacy regulations".

          If the "legacy regulations" said "Altimeters need to operate only transmit between 4.2 and 4.4 GHz, but it doesn't matter if they are affected by transmissions down to 3.7 GHz because no-one is transmitting there" then fair enough. They should be allowed to continue and the 5G fol

          • They should be allowed to continue and the 5G folks will have to go elsewhere.

            And the FCC should be sued into oblivion for selling licenses to something that they already allow overriding and priority use for by another party.

            The 5G folks are doing nothing wrong here (so long as their equipment is operating appropriately, and I would say that given the testing regimes these days to receive an operating license that it will be aside from the odd case of malfunctioning equipment).

          • The FCC doesn't care if the receivers aren't fit for function, that's not what they regulate. If you want to design and sell bad receivers which will stop working if a band which you know can be arbitrarily assigned for other uses that's a civil matter.

            The designers of the altimeters breached their contract with their customers to deliver devices fit for function, not the FCC regulations.

      • making one which accepts 4.2 to 4.4 GHz and rejects anything below 4 GHz would be dead easy. If radar altimeters performing a vital air safety function are not fitted with such things then it is a disgrace for which the altimeter manufacturers should be held accountable.

        And aircraft so equipped should be grounded immediately as not compliant with any standards at all and a menace to society. Equipment that defective is dangerous to people on the ground as well as in the air.

        Persons defending the use of

  • Don't worry about the phones directly. If 5G can potentially interfere with an altimeter, then what about potential attackers? Could someone with a small transmitter dumped in a waste bin cause enough concern to halt operations at an airport for hours?

    Just design the altimeters to fail safe. If they can't get a reading, or the reading is not within plausible range, then discard the data and fall back to alternative navigation. I would hope all aircraft with radar altimeters are capable of doing that already

    • The "discard if bad" is a good approach which is normally used in aviation.

      There are a couple of problems with it however - first, what is "bad data" in this regard? What if the altimeter is only off by 50ft? Thats enough to cause a bad heavy landing, or come too close to terrain etc but not enough to say "this is obviously bad data".

      The second problem is that the crew need to react properly to the situation - take the AF447 crash for example, where the autopilot *knew* it had bad data (sensor disagreemen

  • Not a harmonic. Intermod products there are unlikely. Doesn't anyone ask people who understand RF?

    • Yeah. The avionics are very well designed and I doubt that front end overload or intermods would be an issue. Eh, a second harmonic from the galley microwave plus the local C band weather radar might be more of a threat than a 5G tower or on board 5G phones.

      Sounds like high class FUD to me. The 5G could always be filtered out before it caused any potential problem.

  • Although it might sound easy to simply say "fix the radar altimeters by simply inserting a filter" or something like that. The problem is with transport category aircraft where I believe most of the problem arises, nothing, I mean NOTHING gets installed into an aircraft that isn't inspected 10x over, after going through the engineering specifications, testing, blah blah blah. This testing and certification has to not only be for the instrument but for the airframe too.

    The cost of certification for the fix

    • The cost of certification for the fix can be millions of dollars and months or years to procure plus tens of thousands of dollars per airframe along with downtime etc.

      And that's all the FAAs doing too. That doesn't give them the authority to stomp on the FCCs territory.

  • Not a real problem (Score:2, Informative)

    by BobC ( 101861 )

    First, radar altimeters (RA) aren't vital equipment in any aircraft. Most private aircraft don't have them. It's a rather antique technology that is grossly overpriced for what it delivers.

    Pretty much every aircraft flying today has a GPS with WAAS (or equivalently, A-GPS) capability that yields better than 1 meter position and altitude accuracy.

    We've had FREE world terrain maps with better than 10 cm accuracy for well over a decade, since the STRM (Shuttle Radar Topography Mission) datasets were released

    • Dude, radar altimeters are a primary component of any TAWS and hence a vital part of avionics. GPS receivers, on the other hand, are not considered essential. That small sirplanes don't have it means precisely nothing - they don't have a lot of things that are mandatory for larger aircraft, like ADS-B or TCAS.

  • by aepervius ( 535155 ) on Monday November 08, 2021 @01:22AM (#61967523)
    There is a separation of 200 MhZ but I don't know enough about equipment and bandwidth whether there is much bleed between 3.98 MhZ and 4.2 MhZ, I would think with modern equipment the frequency bleed would be minimal but hey, I am not a radio engineer. OTOH I know about 1/r^2. And thus even if there is a bleed, the solution to the above problem is simple : limit the power of 5G mast to the distance of airport so that in an envelop of flight landing or taking off (that one could be dozen mile though) the power of the signal is negligee. Anywhere else from airport anyway flight will be far away (km high) so the power of the signal should be low enough. All info I can find about range says 500 meter effective range, so I assume they won't blast terawatts from those tower if the range is so low.
  • I don't believe the FAA can regulate radio frequency use directly - that's the FCC's job.

    However under FAA Part 77 [ecfr.gov] they could determine that 5G was an "obstruction to air navigation".

    ...standards used to determine obstructions to air navigation that may affect the safe and efficient use of navigable airspace and the operation of planned or existing air navigation and communication facilities. Such facilities include air navigation aids, communication equipment, airports, ...

    So the FAA could issue a "N

  • This is not a problem, because in the green new world, aviation will be eliminated in favor of sailing.

  • My question is, is there a real risk of interference here? Or is this simply a ploy designed to undermine 5G while the question is tied up for years in court?

Consider the postage stamp: its usefulness consists in the ability to stick to one thing till it gets there. -- Josh Billings

Working...