back to article Quit worrying about 5G C-band and crashing aircraft, US govt eggheads sigh

Fears that 5G C-band signals could disrupt aircraft altimeters are misplaced, US government researchers claim in a report, saying that current efforts to filter any potentially dangerous frequencies are likely enough to combat problems.  The National Telecommunications and Information Administration's (NTIA) exhaustively …

  1. Anonymous Coward
    Anonymous Coward

    Excellent. The proper amount of greasy money finally made it into the appropriate ungreased palms, so we can all breathe easier.

    1. markr555

      Said with all the conviction...

      of an anonymous coward :-P

    2. Filippo Silver badge

      Let me get this straight.

      Someone claims that 5G does a bad thing. At which point one of three things can happen:

      ⁕ Nobody checks ⇒ we assume the bad thing is true.

      ⁕ Somebody checks, and finds the bad thing to be true ⇒ we know the bad thing is true.

      ⁕ Somebody checks, and finds the bad thing to be false ⇒ we assume the guy who checked was corrupt, so the check is invalid, so we still assume the bad thing is true.

      Exactly how do you disprove the claim? You have to check yourself? That's tricky to do with aircraft, and even if you did, by the above logic you couldn't convince anyone else anyway...

      1. Strahd Ivarius Silver badge

        it is like the need to put phone in "airplane" mode when flying, because everybody knows that 2G/3G/4G has no effect on a plane electronics when no phone tries to connect...

        Someone did a test to see what would happen.

        (Bluetooth seems to be authorized, I suppose someone paid the needed fees)

  2. trindflo Bronze badge

    did they look at all for someone intending on causing mischief?

    From what I gathered reading the report, they tested equipment being used as intended. I didn't see where they looked for things that could be intentionally done to cause problems: e.g. a capacitor to the crystal. If you only need to shift the frequency a little bit...

    1. DS999 Silver badge

      Re: did they look at all for someone intending on causing mischief?

      If you are looking at malicious actions then you don't need to look at C band 5G. The problem is with frequencies several hundred MHz away, and it has been claimed some aircraft's front end RF filters aren't good enough to reject that. If you are malicious you will broadcast directly on the frequency the aircraft are using, which obviously will cause them plenty of problems.

      People broadcasting on whatever frequency they please will cause no end of problems, aviation is just the tip of the iceberg. That's why the FCC regulates who can broadcast what on what frequencies under what conditions and under what power limits, and prosecutes those who violate it. You can't protect against such malicious actions anymore than you can protect against someone deliberately crossing over the dividing line on a two lane highway to crash head on into you.

      1. markrand

        Re: did they look at all for someone intending on causing mischief?

        Yes, the FCC regulates who can broadcast what on what frequencies etc. The FAA can ground aircraft with non compliant radalts, but it should have no input on the correct use of allocated frequencies.

        1. DS999 Silver badge

          Re: did they look at all for someone intending on causing mischief?

          The FAA does have input on safe flying, and if it is true that use of C band 5G will cause problems for some planes (even if it is due to a poorly designed receiver on those planes) then the FAA should have the power to temporarily limit use of C band 5G where those problems may result.

          The problematic planes should then have to update their equipment within a specified timeframe to address the issue, it can't be a permanent limitation unless the companies who paid for C band 5G frequencies are going to be refunded.

          1. Anonymous Coward
            Anonymous Coward

            Re: did they look at all for someone intending on causing mischief?

            This is why the FAA should immediately ground the planes that are non compliant with the FCC mandatory regulations, and let the FCC do its work.

            The FAA has absolutely no legitimacy to block the use of airwaves that has been authorized by Congress.

  3. A.P. Veening Silver badge

    I'd say FAA could use their limited resources better at making sure airframes are truly flightworthy instead of wasting it on superfluous rules about radalt frequencies and interference from a non-problem.

  4. nijam Silver badge

    Given that the the signal from 5G masts primarily propagates horizontally, preventing masts from being close to airport flight paths might lead to worse interefence because mast further away might need higher signal strengths to cover the dead spot near airports. Or maybe not. I'm sure someone has though of it...

    1. DS999 Silver badge

      There isn't any need to cover airports with C band 5G. There are already so many 5G frequencies that other frequencies can cover airports and the area immediately surrounding the airport. I imagine they'll be able to resolve this issue via retrofits of aircraft with poorly designed receivers, but if not there are other alternatives that will work well.

      For one, airports are the perfect place for mmwave 5G, which is designed for denser areas (airports have a ton of people in a small space) but have limited range and require line of sight (not an issue for an airport, which have wide open areas with high ceilings that could probably be covered by a handful of mmwave microcells) Sure the US is AFAIK still the only place deploying mmwave 5G (and hence the only place where iPhones include mmwave 5G antennas) but since this particular issue involves the US it seems like a good solution.

      If they say "no C band 5G within 5 miles of an airport" then other bands can cover the area around the airport, and mmwave can cover the airport itself.

  5. Leedos

    This needs further consideration...

    These are all valid points. However, asking owners of the ~30,000 airplanes that are affected by this to upgrade their avionics or install some kind of filter is a bigger ask than it seems. It will certainly be a more expensive fix than to avoid the interference in the first place. 5G is great and there are too many unfounded claims against it, but this isn't one of them. I have a few friends that are pilots that have experienced interference. These airplanes are of course older models and have old avionics to go with them. There was a whole lot less RF interference to deal with when they were designed. Swapping out equipment in airplanes is much easier said than done. You can't simply take out one part and swap in another that works better. It's not allowed by the FAA, for good reason. Kinda like how the 737 and 737 Max really aren't that different so let skip the recertification process. Even on a smaller aircraft like Cessnas, you can't just change out one part with a newer equivalent. Even though in most cases, a modern replacement would almost always be a better choice. Edge cases can and do happen. Removing and replacing equipment with something else can require special exemption certifications from the FAA. This is usually a costly endeavor. You would need to design, retrofit, test and upgrade all affected aircraft of every affected make and model that has been produced and are still cleared for flight. Then the FAA needs to sign off that these modifications should never be a contributing factor in any future accidents. I don't think the FAA would like to test these waters again. There are other bands that carriers can operate in that are not a problem. I think most of us can deal with not having a gigabit internet connection on our cell phones while at the airport if it means there won't be a chance of an accident. I can deal with not having 5G at the airport in the near term. If that's an issue for you, leave AT&T or Verizon and switch to T-Mobile.

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