back to article 5G frequencies won't interfere with airliners here, UK and EU aviation regulators say

5G mobile phone emissions won't harm airliners, Britain's Civil Aviation Authority (CAA) has said, dampening down excitement in the US about mobile masts interfering with airliners' altimeters. In December the US Federal Aviation Authority (FAA) issued warnings about the 5G C-band frequencies used for mobile phones, saying the …

  1. Mike 16

    Told to turn off?

    I believe the airline will tell passengers to turn off phones (or put them in "Airplane mode"), and I can believe that some passengers will tell the phones to turn off (or go into airplane mode).

    What I have trouble believing is that all phones will actually turn off all radios, let alone the other stuff.

    1. IGotOut Silver badge

      Re: Told to turn off?

      It's transmitters, not recievers.

      1. R Soul Silver badge

        Re: Told to turn off?

        What does a phone do when it's sending data?

    2. Lee D Silver badge

      Re: Told to turn off?

      If you had to rely on individual passengers turning off their phones in order to not crash the plane, there's no way you'd be allowed to have a phone anywhere near a plane and you'd be scanned for them before you set foot near them.

      The interference is minimal and fleeting and non-critical or it wouldn't be licensed in the first place.

      1. LisaJK

        Re: Told to turn off?

        There were documented incidents in the past where interference by mobile phones to the aircraft systems actually occurred and is the reason why all consumer electronic equipment was required to be turned off at one time. A few years later they relaxed it to aircraft mode and more recently they generally don't worry.

        I seem to remember it was either during the analogue era or early 2G / GSM era.

        I remember one incident occurred when an aircraft was diverted, so everyone got out their phones to make calls and interference was noticed. I don't know the nature of the interference.

        I'm sure more detailed info is out there in the Googleverse!!!

        1. cageordie

          Re: Told to turn off?

          I've never heard of any proven claims. It's your claim, provide a link to proof. All I find is "well it's bound to" and "well it must have".

          On the other hand, I have received text messages and images from a friend flying over Nevada in a Cessna. GA pilots do it all the time. Thousands of phones are left on on flights every day.

          1. JetSetJim

            Re: Told to turn off?

            It has been studied by Boeing and some instances where there has been strong correlation between use of portable electronic devices and interference with plane systems. Those instances are >20yrs old, and none of them were for phones. However, the report goes on to state:

            The laboratory results indicated that the phones not only produce emissions at the operating frequency, but also produce other emissions that fall within airplane communication/navigation frequency bands (automatic direction finder, high frequency, very high frequency [VHF] omni range/locator, and VHF communications and instrument landing system [ILS]). Emissions at the operating frequency were as high as 60 dB over the airplane equipment emission limits, but the other emissions were generally within airplane equipment emission limits. One concern about these other emissions from cell phones is that they may interfere with the operation of an airplane communication or navigation system if the levels are high enough.

            I don't know when this report was generated - phones may have moved on since then...

            More modern planes are designed with mobile phones in mind, and at least some are perfectly happy for you to have your phone on while the plane is in motion - but I would say that cell-towers do not like phones entering coverage at 200+ mph (take off), and certainly not at 500mph+ (cruising) - but cell towers are not likely to notice a phone up at 30k feet as their antennas don't point upwards in general.

            If plane altimeters use the same frequencies as cell towers nearby, then I wouldn't like to rely on that measurement. It's easier to tell folks to turn their phone off than it is to make sure all network cell towers that could conceivably interfere not use that frequency. Or they could have not sold off that frequency, or they could try shifting the frequency of operation of the altimeters (!).

            It should be noted that mobiles using ~4GHz spectrum probably won't have the best range. It's not the highest frequency for 5G, but it's not going to have the range of 800MHz at the same power levels.

        2. FILE_ID.DIZ

          Re: Told to turn off?

          Yup. That must have been what brought down UA93 into that field in Pennsylvania... the people calling their families for the last time.

    3. Annihilator

      Re: Told to turn off?

      I put my phone in airplane mode yesterday. Siri told me that she was serious and not to call her Shirley.

  2. Caustic Soda

    Comms regulators know nothing about RF? I am shocked....

    It's been clear for a long time that OFCOM is staffed by people who know more about Eastenders than electronics, and that their comms reg stuff is much more focussed on people saying rude things on the TV and radio than it is on anything wireless. Cabled stuff falls somewhere in between ("When in doubt, blame Openreach!")

    However that things are as bad everywhere else is a bit of a worry. There is no danger that 5G is going to interfere with anything on frequencies so far removed and I doubt very much that radio altimeters exhibit the poor selectivity of a Midland 1001 CB radio.

    1. Yet Another Anonymous coward Silver badge

      Re: Comms regulators know nothing about RF? I am shocked....

      >interfere with anything on frequencies so far removed

      But pirate radio Laser558 on 558KHz was a threat to all UK transmissions and air traffic control radar and the RAF and national security.

    2. Anonymous Coward
      Anonymous Coward

      Re: Comms regulators know nothing about RF? I am shocked....

      Oh so the OFCOM people who arrived onsite at work looking for sources of spectrum interference impacting the local Voodofone cell site were imaginary? They were pretty clueful and pointed us fairly closely to offending item on each occasion. They do still have competent spectrum police.

  3. IGotOut Silver badge

    So according to the good ol' USofA

    The way to stop an invasion of your country is to roll out 5g.

    Thats explains why China is a world leader.

  4. Yet Another Anonymous coward Silver badge

    Odd safety standard

    > been no confirmed instances where 5G interference has resulted in aircraft system malfunction or unexpected behaviour,

    At the launch of the Titanic there had been no confirmed instances when crashing a steamship into an Iceberg resulted in unexpected behaviour

    1. Jim Mitchell
      Paris Hilton

      Re: Odd safety standard

      Is that actually true? There were lots of steam ships and lots of icebergs prior to the Titanic.

      1. Col_Panek

        Re: Odd safety standard

        Running into an iceberg results in expected behaviour.

      2. John Brown (no body) Silver badge

        Re: Odd safety standard

        True, but none of the previous steamships were advertised as "unsinkable".

        <Small voice from the back> Is that actuially true?

  5. Anonymous Coward
    Anonymous Coward

    A small proposal

    Maybe it's just me, but if any of these three/four letter agencies would actually bother to properly MEASURE this instead of talking assumptions and/or bollocks from behind their desks there could even be some decision taken on a factual basis.

    I know it's too logical a suggestion from a non-bureaucrat, but, you know, I kinda like to know rather than to assume.

    Personally I would be very happy if the signal was weak when I came in - I'd be perfectly OK with people's phones only starting to work when we're actually on the ground.

    1. steelpillow Silver badge

      Re: A small proposal

      5G radiation emissions are indeed well characterised. That is not true of the susceptibility of every darn radio altimeter on the market. Those were designed to standards which did not anticipate 5G signals clouding their patch, and to go out and retest every model and installation variation flying would be nigh-on impossible.

      When assumptions and bollocks are all you have to analyse your risk with, it pays to be cautious.

      1. Refugee from Windows

        Re: A small proposal

        Of course the antenna pattern of 5G sites will be primarily horizontal, as airborne 5G use is not to be expected, their users are on or near the ground.

        Radio altimeters will send their signal pointing at the ground, and the receive antenna will be pointed at the ground to receive the reflection. Also radio altimeters will use a narrow band signal, whereas 5G is broadband, so less spectrally intense.

        They're not likely to clash unless you briefly fly over a 5G site, even then you'd have a lot of discrimination between the two signals and they are not exactly the same frequency.

        1. David Hicklin Bronze badge

          Re: A small proposal

          I always thought that the issue was that the phone would see half the countries masts at once - something it was not designed to do - and get overwhelmed working out which one to connect to

          1. JetSetJim

            Re: A small proposal

            Not in general - there is little use in radiating upwards for most masts. At lower altitudes, this can be an issue - climb a skyscraper in London and you get more visibility of masts a long way away, but as you go higher this effect is reduced (not necessarily eliminated - but at the very least you're dealing with the inverse-square law for distance from mast, coupled with the beam shape, so you should get a very low signal).

            It's more an issue on the network with a phone on a call running through cells every few seconds on take-off/landing as the plane goes at ~200mph

            1. gnasher729 Silver badge

              Re: A small proposal

              Couldn’t the signal towers at least in flight paths be programmed not to beam upwards? Like “don’t connect to anything higher than 100 feet”, assuming they don’t build high rise flats in the flight path to an airport?

              1. JetSetJim

                Re: A small proposal

                Geolocation of a mobile in 3D is very tricky as all the signals the mobile is measuring are effectively at ground level. Even if you had pure line of sight and excellent timing resolution or perfect power control, the differences in signal measured needed between heights would be tiny, and the standards don't allow that - measurements are basically a short int for signal power and/or quality for each cell reported.

                Our you could mandate phones use GPS to work it out and report to the base station. Also bad, as it won't work indoors.

                None of the above stops the mast from radiating a bit into the air, anyway. You'll not be able to stop that (and most masts are already directional) as the signal just bounces off everything.

                The solutions are either to widen the guard band, mandate a better cutoff on used frequencies (for all devices concerned), make better altimeters or keep everything suitably far apart to avoid the issue (assuming tests show there is interference).

    2. A.P. Veening Silver badge

      Re: A small proposal

      I know it's too logical a suggestion from a non-bureaucrat, but, you know, I kinda like to know rather than to assume.

      I don't mind those agencies making asses of themselves (already are as far as I am concerned) and you will have to take care of yourself in this regard, but I take exception to being made an ass.

  6. Kev99 Silver badge

    Has anyone in the US actually tested 5G in real world scenarios? Not in a lab or on a computer, but in the air in real life situations. Keep in mind that dihydrogen oxide has been proven time & again in real life to be deadly but it hasn't been banned.

    1. Yet Another Anonymous coward Silver badge

      >Has anyone in the US actually tested 5G in real world scenarios?

      Well obviously not, until we know if it's safe to test in the real world, we can't test it in the real world.

      See also prescribing vaccines to under 5year olds before they have been tested on under 5 year olds.....

    2. Sixtiesplastictrektableware


      "Real world scenarios"?

      Are you mad? Do you have any idea how much it would cost to fly an empty jet with some kinda 5G dummy transceiver and attempt to empirically find this information out?

      Can you even imagine a world in which we did that sort of thing all the time? On purpose? I'm telling on you, for your very provoking and incendiary comments.

    3. Dante Alighieri


      testing isn't agile

      (break it first...) nb a Boeing did it and ran away

  7. _LC_

    "5G frequencies"?

    5G is just a protocol that isn't bound to any frequencies. Consequently, the frequencies in use differ from country to country.

    1. JDPower666

      Re: "5G frequencies"?

      As stated, and illustrated, in the article.

      1. _LC_

        Re: "5G frequencies"?

        Yes, but drop the silly "5G frequencies".

    2. Anonymous Coward
      Anonymous Coward

      Re: "5G frequencies"?

      I thought 5G was a marketing term?

      1. JetSetJim

        Re: "5G frequencies"?

        Nope, it's an entire suite of protocol implementations that are hideously complicated but enable ridiculous speeds with very low latencies (admittedly gobbling spectrum to do it).

        4G, aka LTE, is a completely different set of documents containing similar material. Similarly for 3G and 2G. They've evolved over time, so you can see some commonality in contents and overall structure of the standards, but they are quite different in the detail.

  8. Anonymous Coward
    Anonymous Coward


    This radio spectrum fight is a continuation of heavy discussions inside the World Radiocommunication Conference hosted yearly by the ITU. Over there the aeronautics "influencers" clash regularly with all other groups about the neighboring spectrums reserved for navigation. Now that there is a strong competition about the radio spectrum allocation in form of the Telecommunication companies, they are obviously trying to shift the battle field into the governmental area.

    From the technical side it is slightly complicated. You definitely do not want a 1500 Watt transmitter anywhere near a receiver which has to detect ground echos with signal strengths in the nanowatt to microwatt range since a damping of the signal by 9 orders of magnitude within a band separation of about 300 MHz is quite challenging and previously not accounted for in the receivers. So the protests are at least understandable since those receivers must now be scrutinized again and probably protected. But nevertheless, this evergoing protests by the navigation guys is quite nerve wrecking for all others trying to get the maxium out of the precious spectrum allocations. And there were years to react since those changes to the allocation map have been accepted a long time ago.

  9. LisaJK

    Surely this is a simple approvals issue???

    Surely, if Radalts are affected by frequencies outside their range of operation or certain 5G equipment is transmitting out of band, then the certification of this equipment should be removed?

    Or maybe the certification compliance requirements has been too lax, in which case it must be tightened. I could imagine that the out of band sensitivity requirement may have been too lax on the Radalts. I'd be surprised if significant out of band 5G transmissions could have ever got through certification.

    1. Bitsminer Silver badge

      Re: Surely this is a simple approvals issue???

      I'd rank it as a conflict of technologies. The radalts are based on frequency-modulated continuous-wave RF, and compare only the frequencies of the current emission against the reflection. There's no discrimination to verify the reflection is indeed your own signal reflected, and not something else.

      Even if the 5G tech (which is digitally coded and far more sophisticated than 1930s era radalt) is completely within it's assigned band, there are causes of interference that are external to the radalt and the 5G transmitter.

      Like, for example, a rusty fence.

      Or anything else resembling a diode, such as any other nearby radio set.

      The aviation folks are right to be concerned.

    2. Fred Goldstein

      Re: Surely this is a simple approvals issue???

      Certification requirements for radalts is too lax -- they date back to 1983, and allow reception on up to "10%" of its bandwidth, which puts it down to around 3.8 GHz. Only a fraction of them are that sloppy, but who's checking? And replacing an altimeter is a big deal; I've heard that it requires the plane itself to be recertified. This would not be a problem if the US had set the power limit on the 3.7-3.98 GHz band to where the UK, for instance, has it, but they allow more power than the cellcos usually actually use. It is that extra power, not really necessary, that creates the risk to the sloppier radalts. So a lower power limit on cells near an airport approach is a reasonable compromise.

  10. Throatwarbler Mangrove Silver badge

    Simple solution

    Every plane must have the pilot's mother-in-law seated behind him or her, ready to point out at a moment's notice that the plane is about to crash by shouting, "Pull up, stupid!"

  11. Anonymous Coward
    Anonymous Coward

    I for one am happy to die as the plane I am on turns a primary school filled with blue eyed little darlings into a blazing fireball, if whoever it is that watches them can have 2.7% more Tik-Tok.

    Not so happy to die for interminable Teams meetings discussing downsizing the powdered instant coffee ration to run 5% longer.

  12. Flak

    Known unknowns...

    "The problem is that no one has ever done a comprehensive study of how good the filters on altimeters are, so no one knows how bad the problem will be."

    Better get on with doing a study then rather than speculating what may or may not happen. We can speculate 'til the cows come home and I am sure there are good arguments for both sides.

    The reality (and outcome of a thorough study) will probably be somewhere in the middle of the two extremes, resulting in a qualified 'go ahead, but within the following parameters'.

    1. Jos V

      Re: Known unknowns...

      There are actually very well defined specs for radalts. And they do get certified:!!MSW-E.docx

  13. jake Silver badge

    Not a lot to see here, kids.

    This is just a silly-ass skirmish in the interminable turf war between the FCC and the FAA.

    Fact: We've been flying planes in and out of airports with 5G surrounding them for years already, with absolutely no problems. For example, take a look at where San Jose Mineta International Airport is located ... right in the heart of Silly Con Valley, one of the first areas in the US to be blanketed with 5G. If there were going to be problems, they would have occurred already ... and probably daily, given the numbers of flights in and out. How many problems have been recorded? Zero. Zilch. Nada. None.

    Management making technical decisions is one of the great evils in today's world.

    1. JetSetJim

      Re: Not a lot to see here, kids.

      Do you know what spectrum had been used for that 5G? Most had initially been deployed in the lower frequencies so the mast gets the range, and it's only recently the higher frequencies are starting to be used.

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