FAA: Airlines Must Retrofit Faulty Altimeters 'As Soon As Possible' (arstechnica.com) 127
An anonymous reader quotes a report from Ars Technica: The Federal Aviation Administration says it finally has a plan for the industry to replace or retrofit airplane altimeters that can't filter out transmissions from outside their allotted frequencies. The altimeter problem has prevented AT&T and Verizon from fully deploying 5G on the C-Band spectrum licenses the wireless carriers purchased for a combined $69 billion. The FAA was urging airlines to retrofit or replace altimeters in recent months and now says it has finalized a plan. An FAA statement on Friday said that "airlines and other operators of aircraft equipped with the affected radio altimeters must install filters or other enhancements as soon as possible."
AT&T and Verizon said they will be able to accelerate 5G deployments near airports in the coming months, but the carriers agreed to continue some level of "voluntary mitigations" in the airport areas until July 2023. Altimeters are used by airplanes to measure altitude. The FAA said a new "phased approach requires operators of regional aircraft with radio altimeters most susceptible to interference to retrofit them with radio frequency filters by the end of 2022. This work has already begun and will continue on an expedited basis."
Additionally, "filters and replacement units for the mainline commercial fleet should be available on a schedule that would permit the work to be largely completed by July 2023," the FAA said, continuing: "The radio-altimeter manufacturers have worked at an unprecedented pace with Embraer, Boeing, Airbus and Mitsubishi Heavy Industries to develop and test filters and installation kits for these aircraft. Customers are receiving the first kits now. In most cases, the kits can be installed in a few hours at airline maintenance facilities. Throughout this process, the FAA will work with both industries to track the pace of the radio altimeter retrofits while also working with the wireless companies to relax mitigations around key airports in carefully considered phases."
AT&T and Verizon said they will be able to accelerate 5G deployments near airports in the coming months, but the carriers agreed to continue some level of "voluntary mitigations" in the airport areas until July 2023. Altimeters are used by airplanes to measure altitude. The FAA said a new "phased approach requires operators of regional aircraft with radio altimeters most susceptible to interference to retrofit them with radio frequency filters by the end of 2022. This work has already begun and will continue on an expedited basis."
Additionally, "filters and replacement units for the mainline commercial fleet should be available on a schedule that would permit the work to be largely completed by July 2023," the FAA said, continuing: "The radio-altimeter manufacturers have worked at an unprecedented pace with Embraer, Boeing, Airbus and Mitsubishi Heavy Industries to develop and test filters and installation kits for these aircraft. Customers are receiving the first kits now. In most cases, the kits can be installed in a few hours at airline maintenance facilities. Throughout this process, the FAA will work with both industries to track the pace of the radio altimeter retrofits while also working with the wireless companies to relax mitigations around key airports in carefully considered phases."
So now we know (Score:3, Funny)
5G interference with altimeters - this is how the bad guys in Die Hard 2 crashed those planes!
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> this is how the bad guys in Die Hard 2 crashed those planes!
... they crashed them by changing ground level by few meters. That's not interference. That's more insidious. Interference can be detected, and they could've landed the plane manually if they suspected the altimeter doesn't work properly.
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changing ground level by few meters.
My brother does this all the time. One day the ground level is here, the next it's down there, with nothing but a big pile of soil at the side next to a 13-ton Komatsu to explain how it happened.
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> this is how the bad guys in Die Hard 2 crashed those planes!
... they crashed them by changing ground level by few meters. That's not interference.
It's not only literally interference, it's deliberate interference.
You have to literally interfere with the existing signal in order to sub your own
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In Die Hard 2, they manipulated the existing signal, having taken over the control tower. They didn't have to sub their own.
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No. As far as I know, altimeters are pressure altimeters. Basically barometers with a scale in feet or meters (USSR). The article seems to speak of radar altimeters,which are in airline traffic far less useful.
For example, height, altitude and flight level mean different things, and their difference is in the calibration. Height is the height above the airfield, so you can land, take off, and fly your circuit safely. That is the value they maladjusted in the movie Die Hard 2.
So actual flight is usually done
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No. As far as I know [...]
The article seems to speak of radar altimeters,which are in airline traffic far less useful.
Apparently your aviation expertise comes from misunderstanding some fiction in an action movie.
The radar altimeter is a critical piece of airline flight safety, and is the basis of the Ground Proximity Warning System and several other systems. It is used constantly during every approach to the landing (starting some miles from the airport, down to touchdown). Also, it is used in flight to help avoid hitting things ("What's the billy goat doing up here in the clouds?!?") when the aircraft isn't exactly where
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Apparently your aviation expertise comes from misunderstanding some fiction in an action movie.
And where does your expertise come from? Random youtube videos?
Also, it is used in flight to help avoid hitting things ("What's the billy goat doing up here in the clouds?!?") when the aircraft isn't exactly where it is supposed to be.
It is one of the single-most important safety innovations in the history of airline service.
What? No. You don't need that much accuracy to ensure you're not going to hit a mountain (or random goat in the clouds?). It is not even nearly one of the most important safety innovations, it just provides an extra margin of safety for landings. A regular pressure-sensor altimeter can be (and has been) used as well. If anything the radar altimeters just let the big planes fly approaches a little closer to the ground (couple hundred feet maybe)
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A regular pressure-sensor altimeter can be (and has been) used as well
My airplane/piloting knowledge is 100% limited to online content I've consumed, so forgive my ignorance. But how would a pressure altimeter know you're about to crash into a mountain? If your instrument is adjusted to know you're 5000' above runway level, that's all it knows. It's not like it has any way to know that a 6000' mountain is there. Air pressure is still the same at 5000' whether your on a mountain face or in open air, is it not?
If anything the radar altimeters just let the big planes fly approaches a little closer to the ground
And, not crash into terrain, at least according to this. [wikipedia.org]"The sy
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And, not crash into terrain, at least according to this. [wikipedia.org]"The system monitors an aircraft's height above ground as determined by a radar altimeter." Modern systems combine that with GPS locations. The article is unclear if GPS elevation is used in the modern version, or it it still relies on the radar altimeter.
As to whether it is the using the pressure altimeters, GPS, or radio altimeter: different systems do different things in different modes, but the short answer (true for the most advanced systems) is: "All Of The Above."
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This is incorrect. The only place the pressure altimeter is accurate is in the vicinity of the airport, where both the current barometric pressure and altitude are known and can be used to calibrate the altimeter. At all other times the altimeter is used for 'flight level', which is used to keep airplanes properly spaced apart (all planes assume the same 'ground' barometric pressure) but is NOT an accurate altitude. And while GPS and the altimeter can be used to PREDICT if you are flying into a mountain,
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And while GPS and the {pressure} altimeter can be used to PREDICT if you are flying into a mountain, they are no substitute for the 'TERRAIN! PULL UP!' immediate warnings of the Ground Proximity Warning System which uses the radio altimeter.
Just to elaborate on the above excellent information...
The radar altimeter is also what is talking when you hear the plane counting down "two hundred...forty, fifty, thirty, twenty..ten" while you're landing.
The (pressure) altimeter is a barometer with a calibration dial on it. When you're at the airport (ie. getting ready to take off, or approaching to land) you turn the knob so that the altitude reads the same as the known airport elevation. If ther is Air Traffic Control (ATC) available, they will tell y
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You're very dismissive of youtube videos, but there are some very good ones by people way more qualified than you. Here https://www.youtube.com/watch?... [youtube.com] is an excellent video by Mentour Pilot (an airline pilot and certified line training captain) explaining some of what the radio altimeter is used for (little unimportant things like autoland for low visibility landings), and how 5G could mess with it. It is involved in the operation of the plane to a much greater extent than you want to pretend.
And here
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I don't have time right now to watch a 20 minute video but I
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Apparently your aviation expertise comes from misunderstanding some fiction in an action movie.
And where does your expertise come from? Random youtube videos?
Based on your ignorant comments, and your piloting claims, I would say that mine is from a lot more experience as a pilot over the last 45 years.
I mentioned the (various professional) Youtube videos to help you learn. But apparently you refused to go look at any of them. This is not a surprise.
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Has anyone really seen any major change in their lives, or phones, etc with the move to 5G?
Honestly, I've yet to see any difference.
I'm still wondering what the push for it was.
It seems to have been causing more problems that it solves.
Here we have the interference with airline instruments.
I never heard if they were able to help solve the interference that 5G was showing with our Hurricane Tracking and prediction equipment....that conversation kinda faded, but I never heard if there was a
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Has anyone really seen any major change in their lives, or phones, etc with the move to 5G?
I can get cheap reliable 300x150 cellular Internet with no data caps in my home. Major change? No, not really. Improvement over 4G offerings? For sure. Finally able to get off Comcast/Xfinity's tit? Priceless..
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That was exactly what I was going to say. Dirt cheap, (for America,) and reliable internet service. I routinely see 600/150, and for less than what Charter/Spectrum offers for 200/10.
And with a couple of strategically placed battery backups, I still have rudimentary internet service if the power goes out.
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Sure.
My car's 3G modem stopped working because 3G got switched off to make room for more 5G. So now I can't locate my car, lock it, or start it from an app any more.
Ok, so that's really a fairly minor change.
Any change that isn't annoying? Nope, none whatsoever. I don't understand the big push for 5G. My 4G phone is fast enough, I can't be bothered to care about getting a new phone.
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My 5G phone with T-Mobile works in Northern Arizona when most Verizon or ATT phones don't. Of course the low-band 5G also doesn't interfere with any of this stuff as it uses the freed up VHF from when tv stations moved digital.
On the UWB 5G it does allow me to have home Internet and directly competes with my local cable company which is good as they need some competition to stave off abusive policies like 1TB bandwidth caps on gigabit Internet service. Of course I can get unlimited bandwidth usage by payin
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That's very interesting.
Is this in the US? If so, what carrier?
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If you've already got T-Mobile, you should see if this is available to you: http://www.t-mobile.com/home-i... [t-mobile.com]
Is the modem a Cradlepoint or Peplink? No. But they give it to you for nothing. My biggest gripe is that, thus far, I don't think there's any way to avoid double NATing if you want to use your own router behind it, (which I do, but it doesn't really affect my usage scenario.YMMV.)
I've been WFH with it for a year; it's been rock solid. Throw a battery on it, and work to your heart's content through yo
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My biggest gripe is that, thus far, I don't think there's any way to avoid double NATing if you want to use your own router behind it
Can't you bridge the interfaces on your own router? I presume it runs dd-wrt or openwrt ;)
Seems Reasonable (Score:2)
Re:Seems Reasonable (Score:5, Insightful)
Don't fly on any airlines that do that. I've been on Southwest twice in the last month, you get two carry on and two checked at no extra charge, plus their seats aren't as packed as the others.
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The airlines are coming back with a vengeance, trying to recoup money lost during the pandemic by gauging travelers for as much as $60 for a checked piece of luggage one way among other "innovative" ways to keep the cost of the ticket down and still make more money, but this one item falls right on them, fair and square.
You sound like you're flying low cost airlines and complaining that you get low cost service. Why do you do that? Do you also ask people to punch you in the face and then complain when your nose hurts?
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Don't be silly. A carbon tax isn't punishment, it's creating intentional incentives and disincentives to change consumer behavior.
Fuel is taxed higher, oil company charges more for it. Filling up a vehicle becomes more expensive. People drive less, and electric vehicles become a more interesting option. That's the whole point.
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Did you really not know this after being told so so many times?
He knows. He's a troll, and/or an idiot. The facts have been presented to him so he either can't or won't know them.
What About the Degridation of Doppler Radar? (Score:2)
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It's actually the other way around. The Doppler Radar interferes with 5G. The 5G is approved by the FCC, which gives it precedence. This collision means that either: Doppler Radar is not approved by the FCC, OR... the FCC is incompetent.
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The 5G is approved by the FCC, which gives it precedence.
Doppler radar is approved by the FCC. I don't know why you thing something has precedence based on simply being approved.
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The 5G is approved by the FCC, which gives it precedence.
Doppler radar is approved by the FCC. I don't know why you thing something has precedence based on simply being approved.
Welcome to the endgame of electromagnetic spectrum crush.
The problem is twofold. The first is that the F.C.C. has bypassed technical acumen for political appointment of reliable wonks. None of these appointments know or understand the physics involved in electromagnetics. You don't just take a vote and change RF.
RF is an unruly beast. I love giving dissertations on all of that, but suffice it to say that at useable frequencies for this sort of thing, signals do not just sit at their assigned frequency
Should have seen this coming (Score:2)
The FAA should have seen this coming years ago and required airlines to update their equipment years ago. It's a bit insane that they waited so long.
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It's a bit insane that they waited so long.
I wonder if FAA had staff cuts like many other agencies, those left have a lot of other tasks and items, 787Max as one of them. Then a hostile executive branch taking a chain saw to existing regulations. There are some regulations that were written in blood decades ago but why they were created has become a mystery for many people.
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The 737 Max has 1 angle of attack sensor, with a buyers option to add a second (which none of the airlines did)
from CNN: https://www.cnn.com/2019/04/30... [cnn.com]
Former Boeing engineers and aviation analysts interviewed by CNN have criticized Boeing’s original software design for relying on data from a single AOA sensor, claiming that those devices are vulnerable to defects.
FAA data analyzed by CNN supports that assessment.
The FAA has received at least 216 reports of AOA sensors failing or having to b
Re:Should have seen this coming - Priorities? (Score:2)
Which is more necessary, 5G around airports or working altimeters?
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Both, and that’s achievable.
This isnt an either-or situation, stop pretending it is.
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We can have both now.
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The FAA should have seen this coming years ago and required airlines to update their equipment years ago. It's a bit insane that they waited so long.
Should have seen what coming? That a new technology will be allowed in an adjacent band thanks to the financial interests of the tech industry bending the approvals process in a way that caused the FCC to not do their one job: prevent license holders from interfering with each other?
Reminder: The first issue with radio altimeters weren't based on any test with radio altimeters, it was just someone running matlab models of the ITU standard and the FCC's 5G allocation and saying: Ya done fucked up, these two
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The FAA should have seen this coming years ago and required airlines to update their equipment years ago. It's a bit insane that they waited so long.
Should have seen what coming? That a new technology will be allowed in an adjacent band thanks to the financial interests of the tech industry bending the approvals process in a way that caused the FCC to not do their one job: prevent license holders from interfering with each other?
Reminder: The first issue with radio altimeters weren't based on any test with radio altimeters, it was just someone running matlab models of the ITU standard and the FCC's 5G allocation and saying: Ya done fucked up, these two cannot co-exist in their current form.
Exactly this. We have to remember that the F.C.C. which was once a technical agency, is now a place where the decisions are made by people with political, not physics or technical backgrounds.
To these folks, you just assign a frequency take the money you were given and all will be well.
It ain't necessarily so! RF does strange and not always intuitive things, and understanding it isn't easy, and politics aren't in the general skillset. So we're crowding the available bandwidth with signals that beat ag
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The FAA should have seen this coming years ago and required airlines to update their equipment years ago. It's a bit insane that they waited so long.
We really have to get better at foreseeing all unexpected problems. ANyhow can you give me the citations that the FAA knew that radar altimeters were going to be interfered with, a long time ago?
Very bad idea (Score:2)
Retrofitting faulty altimeters is an accident waiting to happen!
They should replace faulty altimeters instead.
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If a light bulb in your car fails, you replace the entire car?
No. I replace the faulty bulb. I don't go around retrofiting faulty bulbs when I buy a car. I may retrofit better bulbs.
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3... 2... 1... Government grants to the rescue! (Score:4, Insightful)
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Tail wagging the dog (Score:3)
Let's see, FAA has approved these RADAR-based altimeters for decades, they're safe and don't interfere with other aircraft operations. Along comes 5G and the US Gov't opening up spectrum that now causes interference with FAA-certified altimeters. Why? Two companies who paid a huge amount of money to a large feeding bureaucracy can't use the spectrum they paid for.
All of this lies with the US Gov't and it and it alone should pay for the retrofit or give back the money to the companies who bought the spectrum that caused the interference.
Wait, that's how it should work. Ultimately, we the taxpayer or consumer (same-same) will be paying for this Gov't fuckup. It looks like it'll be coming out of the consumer bucket because we'll be paying for it with higher airfares.
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HIgher airfares is the worst case you can think of? How about planes raining down like hail.
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The RADAR based altimeters aren't the only system that detects altitude on aircraft. There are also aneroid barometer altimeters [google.com] which use a pressure bellows are still in use on all commercial passenger aircraft. The RADAR based altimeters are used for those major airports that require precise altitude control on approach.
Re:What About WiFi? (Score:4, Informative)
Its more important that we have fault tolerant aircraft and not foster a lax safety approach, isnt it?
The whole 5G question here is pretty beside the point, as in this problem of aircraft being susceptible to trivial outside interference should be being solved regardless.
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It should be yes, but be careful with your wording. These altimeters are neither lax, nor faulty, nor do they pose an immediate safety risk when not functional. In fact they are all operating within their original design spec.
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It should be yes, but be careful with your wording. These altimeters are neither lax, nor faulty, nor do they pose an immediate safety risk when not functional. In fact they are all operating within their original design spec.
You want other people to be careful with their wording but you then go on to lie by omission. While these altimeters are operating within their original design spec, their original design spec was inadequate even for the regulatory environment of the times.
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It should be yes, but be careful with your wording. These altimeters are neither lax, nor faulty, nor do they pose an immediate safety risk when not functional. In fact they are all operating within their original design spec.
You want other people to be careful with their wording but you then go on to lie by omission. While these altimeters are operating within their original design spec, their original design spec was inadequate even for the regulatory environment of the times.
Sounds like the pointy haired boss telling Dilbert to design a system that will not have any unforeseen problems.
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Sounds like the pointy haired boss telling Dilbert to design a system that will not have any unforeseen problems.
When the radar altimeters were designed, frequency allocations existed, and they could legally be reallocated. So this is actually about foreseeable problems, if the regulatory landscape is taken into effect. And not doing that is ignorant or irresponsible, there's no third option.
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While these altimeters are operating within their original design spec, their original design spec was inadequate even for the regulatory environment of the times.
No they aren't. Stop spreading bullshit. There's an ITU standard which clearly defines the operational parameters of radio altimeters which they all meet just fine. Reminder: it wasn't even airlines complaining about interference, it was a researcher who pointed out to the FAA that after comparing the ITU standard to the FCC allocation that they two were incompatible.
This was *known*. There was a reason the band was previously preserved for low power downlink and point to point narrow beam communications on
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The thing is rather that a mission critical instrument on a machine that has the potential to endanger hundreds of people is susceptible to interference.
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The thing is rather that a mission critical instrument on a machine that has the potential to endanger hundreds of people is susceptible to interference.
Most in here seem to think that a faulty specification was purposely designed, and that some how it worked perfectly all those years, despite having that fatal flaw, and now stopped working.
Or that system designs can be future proofed, that is designed perfectly immune from any and all problems in perpetuity. IOW, create a system that is not vulnerable to unforeseen problems.
The fact is that the airlines are not the villains, the telcos are not the villains. Even the F.C.C., who placed a 5G system ri
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Why would someone design something that way?
No, it just wasn't discovered 'til now because until now nobody bothered to test it.
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Why would someone design something that way?
No, it just wasn't discovered 'til now because until now nobody bothered to test it.
Exactly.
In a system design, there are various design elements, and many of them play off of or impact each other. There is no perfect system. All aspects are compromises.
Filtering and attenuation of out of band or in band signals - make no mistake, 5G signals have increased noise and actual signal impingement into the radar altimeter band is one of those.
Make no mistake- addition of or mitigation of those OOB's and noise level are seriously unanticipated consequenses, and sensitivity and power level
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You know it's not that hard to stop using 75-year-old hardware on your planes.
If it's not sending encrypted signals, it is vulnerable to spoofing, which means a terrorist (or bored teenager) could bring down the plane. That kind of security improvement should be proactively implemented. It could be as simple as sending a different pattern for each scan. Whether it's because of a spoofer or just interference, if the return signal doesn't contain the pattern you sent, you simply ignore it.
Now I can't tell you
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You know it's not that hard to stop using 75-year-old hardware on your planes.
If it's not sending encrypted signals, it is vulnerable to spoofing, which means a terrorist (or bored teenager) could bring down the plane. That kind of security improvement should be proactively implemented. It could be as simple as sending a different pattern for each scan. Whether it's because of a spoofer or just interference, if the return signal doesn't contain the pattern you sent, you simply ignore it.
Now I can't tell you how to build it in 1947, but I can tell you that by 1980, the technology to do that is commonplace.
Looking forward to your interference proof design, as you sound like you are an expert on this stuff.
I bow to youer superior knowledge - Would you like a job doing this? Because you know a whole lot more about it than the acknowledged experts do.
You can probably eve get a really lucrative job - Are you qualified for TS with the required special access?
I am deadly serious - your country needs people like you,
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Unfortunately, there's another company out there paying me an unfair amount of money to do something else, so I'm guessing the world needs me more over there.
But yeah, feel free to Venmo me 10 million dollars and I'll instead go study electrical engineering and give you an interference-proof radar altimeter design.
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The thing is rather that a mission critical instrument on a machine that has the potential to endanger hundreds of people is susceptible to interference.
All radios are susceptible to interference. In this case, the particular interference was not anticipated by the radio regulatory authorities and the aviation safety regulatory authorities when they authorized their use.
The government was fully aware of warned about the issue several years ago, but the latest administration decided to allow the interference and cause the problem anyway. Their justification is that otherwise China would beat the USA in 5G, and a major campaign plank was 5G dominance.
You can
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You have a couple of instruments that don't agree on a value. Which one is the faulty one?
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When Vodaphone runs a wifi network for my phone then sure we'll go with that. Until then what you're actually asking: "What about connecting to a completely different network which may or may not be wholly unsuitable for the purpose being used?"
5G isn't about you. You don't get multicast PTT radio communications on wifi, or any of the other things 5G actually designed in the spec. There will be reasons airports themselves will want to adopt 5G.
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Is it really that important that we have 5G soaking every last corner of every building on the planet?
Interference problems like this have required products to be re-designed for years. The first example I recall was the widespread use of mobile phones operating in the original UHF band at around 900 MHz. Though there was plenty of RF traffic in the VHF/UHF region prior to mobile phones, e.g. TV broadcast and emergency services, the big difference was putting millions of UHF transmitters in the hands of individuals. This put the interference source only meters away from victim equipment, which is rather dif
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Good points. I guess I'm old and jaded and just immediately assume this is about AT&T and the like needing more profits, instead of updating a current tech that works.
--
Be honest, be nice, be a flower not a weed. - Aaron Neville
They'd don't transmit, so no FCC approval (Score:2, Troll)
The altimeters don't transmit, so they don't fall under the FCC's umbrella.
The FCC is looking to extend their umbrella to cover them, but it's so broad that it's unlikely to pass.
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Pilots have been complaining their altimeters are going crazy when they see 5G signals, so they complained to the FCC and have blocked the rollout near airports. The FAA is now requiring that this problem be solved immediately because the parts to do so are now available.
Re:They'd don't transmit, so no FCC approval (Score:5, Insightful)
Of course a radar altimeter transmits! They transmit an RF signal downward then wait for the return to see what their altitude is. https://en.wikipedia.org/wiki/... [wikipedia.org]
I don't know where this rumor started, but this is the second time I've heard it here. If people don't understand how a radar altimeter works, how can they have an informed opinion of interference, frequency bandwidth, or correction methods.
Those aren't the altimeters in question (Score:3)
Those aren't the altimeters that are having the issue.
https://arstechnica.com/tech-p... [arstechnica.com]
https://www.fcc.gov/document/c... [fcc.gov]
In the past, our discussions of spectrum efficiency have been a one-way effort. They have focused almost exclusively on transmitters. We've put a lot rules in place about how and when transmitters can operate in order to control interference levels. But here's the thing: Wireless communication only exists when transmitters are connected to receivers. Both are vital. Both matter. And going
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Wireless communication only exists when transmitters are connected to receivers.
You're thinking of wired communications ;)
Seriously though, when you say "going forward policymakers need to consider both transmitting and receiving" that's precisely what happened here. The policymakers put rules into place about who's at fault when, and they are simply being applied. The people who didn't take "both transmitting and receiving" into account were the people responsible for these flawed altimeters hitting the market. It was always possible for frequency allocations to be reassigned to other
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OK first, all radar altimeters transmit and receive. There aren't "receive only" models. That's not how they work.
And the problem is not that policymakers don't consider receivers in their policy. The problem is that this part of the spectrum has been pretty clear up until recently so OEMs were able to get away with being lazy. The FCC has for a long time regulated how much interference radios for a given band must be able to tolerate, and radar altimeters are radios. All radars are technically radios and a
Re: They'd don't transmit, so no FCC approval (Score:5, Informative)
It's not that they don't transmit. It's that they don't transmit outside of their allotted spectrum so they comply with FCC jurisdiction which is only for licensing transmissions.
The airlines are complaining about interference outside of their licensed spectrum. And the FCC is saying... tough shit we gave you licensed spectrum, the fact that your equipment is harmed by neighboring bands is your problem.
Low power band meets high power neighbor (Score:2, Troll)
Radio altimeter us
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The airlines are complaining about interference outside of their licensed spectrum. And the FCC is saying... tough shit we gave you licensed spectrum, the fact that your equipment is harmed by neighboring bands is your problem.
If only it was that simple. Spectrum allocation of all sorts of devices are often harmed by neighbouring bands, which is precisely why those neighbouring bands are restricted in all sorts of ways (not just power, and frequency, but also type of modulation, direction of transmission, etc). You can't just say "You get band 4.2GHz-4.3GHz and someone else gets band 4.3GHz to 4.4GHz" without consideration of the application of both.
This problem was known. How known was it? Well there was a reason that the neighb
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I don't know where this rumor started, but this is the second time I've heard it here. If people don't understand how a radar altimeter works, how can they have an informed opinion of interference, frequency bandwidth, or correction methods.
I have two theories:
1. Some people have gotten it beat into them that GPS receivers do not transmit to the satellites. Planes use GPS. So now they think that aviation navigation devices in general do not transmit anything, either.
2. You could have simplified your rhetorical question thusly:
"If people don't understand FUCKING ANYTHING how can they have an informed opinion on ANYTHING."
I will answer it for you.
Most people are dimwit fucktards, and spew nonsense constantly. It makes them feel good. They're bas
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The particular devices being spoken about are receivers only, the transmitter is on the ground.
You should read the sibling thread to yours, someone links to documentation about it.
However, in this case, the issue is that they did not have proper band pass filters installed to limit the receiver properly, it looks like those are now available, so can be retrofitted to the aircraft.
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I start to see one problem here - we aren't always talking about the same transmitter.
The radar altimeter has a transmitter that sends RF downward and measures the return time to get an altitude reading. These transmitters don't have a problem.
The 5G WiFi transmitters on the ground transmit RF near the same frequency to provide data communication in a small area around the transmission antenna. These transmitters will be operating in their assigned frequency allocation and technically aren't the problem a
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The particular devices being spoken about are receivers only, the transmitter is on the ground.
Not sure I'm following what you're trying to say, but the radar altimeter is a transceiver that is entirely on the airplane. There isn't anything on the ground.
What's on the ground is a 5G cell tower that is interfering with the plane's signal.
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The altimeters don't transmit, so they don't fall under the FCC's umbrella.
The FCC is looking to extend their umbrella to cover them, but it's so broad that it's unlikely to pass.
Yes, the radar altimiter does transmit. https://en.wikipedia.org/wiki/... [wikipedia.org]
And it does fall under the F.C.C.'s jurisdiction, as does the 5G section of spectrum right next to it.
I think you are thinking of a pressure altimeter https://en.wikipedia.org/wiki/... [wikipedia.org] which is a passive device.
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Hunh. What do you call it when a "radio altimeter" (aka "radar altimeter") produces an electromagnetic signal, coupled to a tuned antenna, and directs that energy at the ground?
Also, the computer that you wrote this on is not intended to be a radio transmitter. Is it exempt from FCC regulations? Maybe look at the documentation that came with it, or perhaps on some of the writing on the back of the device.
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The altimeters don't transmit, so they don't fall under the FCC's umbrella.
Haha ha, did Trump tell you thaat?
Yup, "Radio altimeters don't transmit" is definitely a nugget I'd expect to leave the lips of Trump at one of his rallies.
I don't think this ignorance is related to politics.
For an anecdote, two days ago an ultra-liberal Democrat tried to explain to me that GPS receivers transmit your position to the satellites, and made several other similarly amazing technology explanations related to such things as how mobile phones and highway toll transponders work. They did not understand anything at all (not even at a 7th grade level) about electronics or physics, much less about computer-related technology. This person holds a recent d
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If so then FCC electromagnetic radiation testing shouldn't have passed them. Isn't this really a case of design requirements changing long after something has been designed, manufactured and sold?
No, they are not faulty. They met the design requirements at the time they were given that bit of spectrum.
After 5G came along, they proved not capable of coexisting with the 5G signals, and the RF products that exist with the newcomer.
This is a somewhat similar problem that happened when the telcos attempted to operate right next to GPS frequencies. They claimed that it would be no problem. People who understand said "you are going to wipe out GPS signals in the adjacent band, the products of your sign
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Or rather, more precisely, the FCC has successfully pressured the FAA to take the hit (more accurately make air operators take the hit) for the FCC's incompetent spectrum-allocation technical decision.
Of course. Replacing the radar altimeters is by far less expensive than dumping 5G. It's a financial decision. About the only somewhat fair decision would be to have the telcos share in that cost.
Politics over physics in action. Tomorrow we're holding a vote on the second law of thermodynamics.
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Politics over physics in action.
That's a ridiculous thing to say. Physics is not on either side in this argument at all. Physics says both sides can't share the same spectrum, it is equally against both sides, and for neither. Politics says that the most expedient solution be chosen, but expediency is often measured beyond the current situation because you have to consider precedent and other repercussions. It doesn't matter which solution costs more now. What matters in the really real world is twofold, first who can exert more influence
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Politics over physics in action.
That's a ridiculous thing to say. Physics is not on either side in this argument at all.
Ridiculous it might be, but it is likewise truthful. Physics is deeply ingrained into this issue. Politics is deeply ingrained into the present day F.C.C.
We see the efforts of politicians to align science to their ideology all the time. Teaching young earth creationism is a big one in the USA. Squelching science regarding the energy retention characteristics of an atmosphere by the composition of that atmosphere is another. My favorite though, is Lysenkoism where communism adopted the idea that life can
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See? You believe that the political trumps the physics - thank you for admitting that at least.
Here's the thing about that theory, if an insurmountable principle of physics were at fault then they wouldn't be able to solve the problem with a retrofit. One user would have to be reallocated away from the other. But since it's possible to make gear that works when there's a noisy neighbor, that should always have been done from the beginning, and then we wouldn't be having this problem now. The whole argument that "there was nobody using this much power on the neighboring allocation at the time" is will
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See? You believe that the political trumps the physics - thank you for admitting that at least.
Here's the thing about that theory, if an insurmountable principle of physics were at fault then they wouldn't be able to solve the problem with a retrofit.
Can you point out where I wrote that this is an insurmountable problem? I'd love to see that post.
It isn't insurmountable. But the altimeter system as is, which was designed and built according to the conditions at the time, functioned quite well until this.
How can this be taken care of? Practical ways ensue.
Aside from placing 5G well away in frequency. Which ain't gonna happen.
Increase radar altimeter transmitter power, add digital signal processing to the altimeter. Build receivers that are muc
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You're arguing what is clearly a minority opinion even among your peers, based on the fact that only a minority of devices are affected because the manufacturers took these realities into account when designing them. Despite your apparent clear superiority in knowledge of these matters, both those responsible for the creation of the bulk of the potentially affected devices, and those responsible for regulating them disagree with your position. As such, it seems unrealistic for you to present your opinion as
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Sure, everyone is wrong but you.
We have rules about frequency allocations specifically to avoid problems like these.
The engineers who designed these altimeters and the managers who signed off on the designs are the ones at fault here. They collaborated to create a future problem for profit. It was part of the legal landscape at the time that frequency allocations could be resold for other purposes. Good engineering takes the regulatory landscape into account. Were these devices so old that they predated fre
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Long before precise and effective ways of frequency filtering in their receivers was possible.
The FCC only defined the frequency allocations long after that, and ERRED in allowing high power 5G in closely adjacent bands.
They should have done the technical checks first, before deciding how narrow the aviation band allocation would be, and how close they could allocate a high power other application.
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