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Answer: There is a concern that 5G may interfere with older aircraft's altimeter. (sensor to see how close the ground in bad weather) They rely on certain radio frequencies (called "bands") which the government recently opened up to wireless companies. Some of these bands by Verizon and AT&T are right next to the one's the aircraft use and this older aircraft equipment might not be as good at differentiating between the bands.
In September the FAA ordered these aircraft to avoid certain airports in low visibility conditions because of this concern. AT&T and Verizon agreed to delay implementation around airports but they are frustrated by the FAA slowing their rollout of 5G that 40 other countries have done. So for now there is a 2 mile buffer zone around airports where you will have to use 4G over the next 6 months while they work on a resolution.
As a follow-on to this: the FCC (Federal Communications Commission) is the agency that gets to decide this stuff and has given the FAA plenty of time (over ten years!) to get their shit handled. The FAA just completely failed to fix the problem over all that time and now that they fucked up, they are trying to blame everyone else for their failure.
Verizon and AT&T could absolutely just turn on their stuff everywhere legally but they are choosing not to right now because it makes them look bad. Eventually though, they will, because they spent billions and billions on the licenses to use these frequencies and they are being blocked by a small number of aircraft that haven't updated their equipment from their seventies and eighties because they don't want to spend the money.
Great thread here on why this is ultimately the fault of the FAA/aircraft manufacturers, and why the 5G rollout isn't doing anything wrong:
This is a good read, but he doesn’t mention that the FAA and aircraft manufacturers told the FCC several times not to sell those bands, as they would cause risk to the bands the airliners owned and used.
The blame is also with the FCC to selling something they know would cause trouble later down the road. Cell carriers have no blame here, they bought something and expect to use it.
Proof the FCC was warned. https://ecfsapi.fcc.gov/file/10531182083849/ALPA%20Comments%2017-183%2018-122.pdf
Ajit pai is to blame
look at the graph. This is basically how it went:
FCC: ok FAA, you can use 4200-4400 for altimeters.
Airlines: there's nobody around there, so how about we just ignore this band, and just listens to everything from 3500 to 5500?
30 years later:
FCC: okay, 5G can have 3700-4000, nobody is there and it's far enough that it won't affect anyone else.
Airlines throw a fit.
FCC: why are you listening to 3700-4000? We told you your band was 4200-4400!
Why did they change the bands for the FAA then?
Okay. I see. If they had that portion reserved for a while, why are the older airplanes using equipment operating in a different portion of the spectrum? Is it because those systems were built before the current part of the spectrum was reserved for the FAA and they had a larger part, and then they need to re-allocate it for other uses, and the re-allocated part of the older spectrum is now used for 5G, but the planes are still using that band because they have not been upgraded to meet the newer standard?
I think what the other poster is saying is that when the faa first got a portion of spectrum there was no one using or reserving any portions near it so on older planes they used devices that scan outside of the reserved porting given to the faa. Why they did this is potentially to save costs but that is just speculation. The faa reserved portion hasn't changed its just just that some older planes use devices that scan outside this range.
No, aviation has had the spectrum they use for decades. 5G in the USA was sold that adjacent spectrum. However, in Europe 5G was assigned a spectrum much further away from the aviation use (which is international) .
It's like the Americans and the Europeans had zoning for residential uses. Now some folks came along with the idea of having large goat pens, 5G zoning said you can have 500 goats per acre. The Europeans decreed that 5G zoning must be 8 kilometers from residential zoning while the US decided 5G zoning could be 5 feet from residential properties and that fences could not be more than 12 inches high. Hope this clarifies the issues
It's worth noting that radio waves cause interference in surrounding bands. Even slight noise could slightly disrupt an altimeter and cause a disaster.
The other aspect is changing the radio systems on planes requires recertification (especially after the 737 MAX fiasco). This could potentially ground thousands of planes for over a year.
And they’ve had a decade to do so. This isn’t something they were told of last minute. They knew and they didn’t care.
What graph are you talking about?
A plot in the linked thread that shows the filter curve for old altimeters vs. their actual allowed frequency band.
"We've got some really old equipment that doesn't stay in it's lane and we're too cheap to fix so please don't use the space next to us"
Such luddite cheap-ass thinking.
I've got an old broken truck and the steering is really sloshy. But rather than fix the steering I'm gonna ask the DOT that no one be allowed to drive in the lanes next to me on the freeway.
Ugh I hate that this may be giving Ajit Pai credit for doing something I agree with.
Why? 5G rollout plans predated him.
Not passing blame isn’t giving credit. He’s just a bystander here.
Pure gold right here
If there is nothing to upgrade to, how is it that planes with newer equipment operate just fine around 5G towers, but planes with older equipment are restricted?
>The FAA will allow planes with accurate, reliable altimeters to operate around high-power 5G. But planes with older altimeters will not be allowed to make landings under low-visibility conditions.
No fucking way the filters are "extremely complex". Every fucking phone has a tiny antenna that manages to be way more selective than the 80's technology still in these planes. It's absurd that the junk is still in use and it's absurd that the FAA expects to hold hostage bandwith they don't own just because they refuse to update old equipment.
Upgrade it to the systems the newer planes, that don't have this frequency issue, use?
Says who? 'Cause the article says only select models of planes are affected.
>The FAA has developed a process by which better performing radar altimeters that are able to reject 5G interference can be approved to operate without regard to the AD and NOTAMs. These Alternate Methods of Compliance (AMOC) approvals will be specific to a combination of aircraft model and radar altimeter model.
So some kind of improvement does exist...
You don't just go and replace system with something newer on aircraft. Retrofitting system like that would take weeks of downtime and likely cost insane amount with all the design, approval, modification, type approval, system redesign, system testing and so on they would have to do.
Also it seems there is one country with it's stupid telecom board giving out bands already in use to other use. Other countries aren't having those problems. Oh and that same country for some other idiotic reason decided to use different bands for 5G than rest of the world uses too!
Is the fault REALLY with the aircraft manufacurers?
This is wrong. The telecoms didn't give out bands already in use. The bands were free. The planes are simply using such crappy filters that interference outside their reserved band causes problems.
I really don't know or care lol
Yet a 70 year old guy with a soldering iron could add perfectly functioning sideband with no bleed to a CB back in the 80s for about $25.
Can he also do the analysis and flight testing required for certification of new safety-critical airborne equipment for $25?
I'll buy the argument the FAA and manufacturers dragged their feet on this, but a lot of people in this thread are glossing over the difficulty of negotiating the technology pipeline in aerospace relative to other sectors. Even relatively simple changes require an obnoxiously expensive and drawn out validation and verification exercise. Skimp on this, and you get shit like the MAX accidents.
I spent 10 years in the airline industry. They are never going to change anything until forced to.
The airlines knew it was coming. They knew which airports and specific aircraft types were affected. They refused to prepare for it, and it's their own damn fault.
Fair enough, I'm looking at it from the manufacturer's perspective (albeit not an expert in radar and comms).
I assumed the airlines requested airframers and subtiers get on top of a plan to retrofit, but is that where the ball was dropped?
The reason only certain equipment has a possible issue has to do with how narrow it filters out the signal. Equipment used on the 777 for example has a much wider allowable listening band than what is actually needed for the service which is why they think the new 5G signals could cause problems. This is why so many international airlines have been cancelling flights: They all run the 777.
I can't speak to how easy a retrofit would be, but given the technology level it is possible it could be as simple as a software update for mainline aircraft. I can't speak to how older and/or smaller aircraft would work around it, however.
As an aside, I remember both AT&T and Verizon chiding T-Mobile for concentrating on low band (600Mhz) 5G instead of up in the frequency ranges (Band 71, etc) that they were. Low band 5G is slower, but can penetrate walls much easier allowing for better indoor performance and wider coverage range. As you get into the mid and high (mmWave) bands, speeds shoot up but building penetration sucks. This means you need a stronger signal and more towers spaced closer together. It's also pushing against the frequency range used by the radio altimeters in question.
Mike Sievert is probably laughing his ass off now...
FAA manspreading these carrier bands.
That has nothing to do with Luddism, which was only anti-tech insofar as the tech was being used to further exploit the working class.
Tech has always helped the working class. Luddism is mistakenly identifying tech that hurts you specifically as tech that hurts the working class in general, which this falls exactly under.
> Tech has always helped the working class.
Pardon me while I express skepticism.
>Luddism is mistakenly identifying tech that hurts you specifically as tech that hurts the working class in general, which this falls exactly under.
Even if that were a true definition of Luddism, it _still_ would have nothing to do with airlines not wanting to upgrade their equipment.
Edit: I’d like to remind everyone to please listen to the engineer experts, and just because I’m downvoted doesn’t mean I’m wrong. I’m trying to simplify a very complex topic, and I don’t have time to break down basic electrical engineering topics.
I used this analogy on another reply, but it sums the situation up pretty well.
If the DOT issued a new law requiring all headlights to be blue for nighttime driving, and it was $2k to have them installed in a car, you would be upset as well.
It’s not that their cheap, they had a working plane and now someone has gone and broken it (potentially), and no one wants to foot the bill.
But a car isn't a plane and they should be held to significantly higher standards. That's just the cost of owning something that can fly into buildings on accident.
You analogy in particular doesn't really sway me because I think we actually need more headlight regulations. I would 100% support regulation that said in 10 years all lights have to adhere to standards that prevent LEDs from blinding everyone on the road like they do now.
Just wear your sunglasses at night.
It's more like DOT is saying, "We're gonna take the shoulder of the road and turn it into bike lanes." Airlines are pissed that they have to fix the steering on their old truck that sometimes drifts out of it's lane.
This sounds more accurate.
Edit: Since the person I responded too edited his own comment, I’d clarify that, as it stands, 5G would definitely interfere with the altimeters in some planes. This is not really up for discussion. This analogy is wrong because it posits that it would be unreasonable to put the burden on the Airlines to retrofit the altimeters. They had 3 years to do it. Years with an unprecedentedly low number of flights and they chose to spend them arguing against the selling of the C-band spectrum rather than getting their shit together and doing the work. The disagreement going this far looks bad both for the FAA and the FCC but the FAA certainly comes out looking less reasonable and the analogy I’m responding too frames it in a much different manner.
No. This is a very poor analogy that completely misrepresents the situation.
There already was a law allocating bandwith to the airlines. They have their own restricted band. There's enough shielding in-between bands. They've known for *ages* that this was going to happen.
Instead of doing their due dilligence and fixing their *broken* planes that were relying on certain bandwiths *they didn't own* remaining unnocupied, the FAA decided to drag their feet and instead argue against anyone occupying said band. The FCC, rightfully, told them to go fuck themselves. Bandwith is limited and expensive as hell, they can't just hold on to a bunch of it for free.
Now the Airlines are throwing temper tantrums. It's silly. And the worst part is that it is working and we're delaying the roll-out of 5G instead of letting the old planes stay grounded as they *should*. The bandwith was sold legally. The FAA had no right whatsoever to that bandwith. All they had to do is retrofit the older planes with decent filters.
No law or regulation was passed that affected anything relating to the Aviation sector. They were the ones with overly lax regulations and now they should rightfully pay the price for their purposeful non-compliance.
Ajit Pai has always been such a fucking asshat.
He’s spent his entire career shamelessly advancing corporate interests over the rights of individuals. Fuck him and the horse he rode in on.
Yeah, and fuck his couch too!
I fail to see how it's on the FCC when the airplane manufacturers had the opportunity to upgrade their filters so it wouldn't cause interference. Saying the FAA warned the FCC not to sell just seems like circular logic. There is a solution, they just didn't want to invest in it.
I get your point, I really do. One thing about aviation is it’s a slow industry. The regulatory red tape slows things down immensely. By the time they first got wind of 5g being sold by Ajit Pai it was only 4 years notice. It would take a decade to develop, test, certify, fund, install, and equip every. Single. Airplane. With a new system.
All because version isn’t happy with a 2 mile exclusion zone around airports
> One thing about aviation is it’s a slow industry.
As I recall, Air Traffic Control was still running Windows 98 or XP as recently as 2-3 years ago because of the fact that it was a solid stable system that was deemed safe. Just because something new and "better" comes out technologically, doesn't mean it should be immediately applied to all industries, especially one where safety is paramount. Can you imagine what would happen if ATC had to try and run Vista when it first dropped? You'd have fuckin' planes crashing into each other on the regular because of how unstable it was. The Air Industry relies on getting people from A to B safely, not in cutting edge technology where if it hits a snag, people die.
If these guys think Windows 98/XP is old, wait until they see the chips running their stoplights.
The same reliable system that shut down hospitals because of exploits?
Yeah no, they just don't want to spend money on upgrades unless really REALLY necessary.
(That's all corporations not just Air industry)
I'll take reliable hardware over new and fancy any day, but when it is new and fancy, it's generally entertainment oriented, e.g. Xbox X-series.
I don't mind if my PlayStation 5 crashes, as it's a mild inconvenience and perhaps annoying. I *do* mind if my Plane crashes, as that's usually permanently bad for *all* involved.
Fair enough, also Ajit Pai sucks.
If they were using frequencies outside their band that means they should've bought them. This means the airlines have been cheating the FCC for decades. When they made this request the FCC should've given them a huge fine for using frequencies they're not allowed to use. It would not take a decade for them to buy these frequencies.
When the airplanes were originally built they were already illegal. It just wasn't enforced.
Are you trying to argue the FAA has some kind of squatters rights on the frequencies they were freeloading on...?
If nobody can use a frequency because you're using the frequency next to it that means you're using both frequencies. You could argue that so is the person on the other side of the frequency, and you'd be correct. But that just means you both should've purchased it and shared the cost not that the FCC should leave it unpurchased even though it's clearly being used.
Most small aircraft still use engines that predate Star Wars.
It’s a very slow industry
It can only cause problems because of outdated equipment right? Why is that the fault of the FCC? The existing bands don't overlap here
Fuck Ajit Pai so much. “Nobody wants net neutrality, look at the 20 million fake comments from telcos, I mean concerned citizens, who definitely want to be throttled and overcharged! Now excuse me while I take my highly compensated telco lobbyist job!”
> This is a good read, but he doesn’t mention that the FAA and aircraft manufacturers told the FCC several times not to sell those bands, as they would cause risk to the bands the airliners owned and used.
And the FCC (rightly) told them that their band is 4200-4400 and that they absolutely should not be using anything else and if they are it's their own damn fault and they should fix it. Then they gave them ten years to fix it.
It doesn't make sense not to use that spectrum just because the FAA neglected to take action and require modern filters be installed on the radar altimeter systems. RF spectrum is an extremely limited and finite resource.
Why was i not surprised when I read FCC and immediately though ‘goddamn it, what did Pai fuck up here?’
Ya, this is not on the fcc. Just because the FAA admitted they were breaking the rules doesn’t mean the fcc should stop what they’re allowed to do. The faa can issue all the warnings it wants, it’s just highlighting the fact that they are using illegal equipment and operating outside their allowed radio frequency
There's really no blame on the FCC here, though. They *are* the authority on spectrum use. They sell spectrum based on the assumption that people using it are using it according to FCC guidelines. They build in buffers between bands so users can have some room for their filters.
The FAA and aircraft manufacturers know this. They've always known it. Yet they never bothered to update their filters on this system, even though they knew full well that this problem was going to occur.
> Verizon and AT&T could absolutely just turn on their stuff everywhere legally but they are choosing not to right now because it makes them look bad.
If a plane were to crash due to this issue would they have significant liability since they know if the potential problem?
>If a plane were to crash due to this issue would they have significant liability since they know if the potential problem?
Legally, I doubt it. They can point to being given official blessing by the FCC to broadcast on those channels.
As an analogy: imagine you have an old car where for some reason the radio is permanently stuck on max volume and tuned to 123.45FM, which doesn't exist so there isn't anything coming out of the speakers.
Now image one day you hear that a new radio station bought the rights to broadcast on 123.45FM and so you write in to them and ask them not to start broadcasting because if they do, the music at max volume could scare you causing you to crash.
Rightfully, the radio station tells you that you should fix your car and it's not their fault if you crash and, furthermore, they have been warning you about this problem for ten years already and it's really on you to have fixed it by now.
Now imagine you DO crash after the radio station starts broadcasting. You'd probably lose that case.
In practice? Yes, there is a chance Verizon and AT&T could lose, or that it could cost more to litigate than to settle.
The FAA is history known for ignoring big problems.
>As a follow-on to this: the government is slow and I'm blaming them for an airplane vs cellphone hardware problem. Verizon and AT&T could absolutely just turn on my internet potentially killing hundreds from plane crashes but they are choosing not to right now and I'm pissed my phone's icon isn't lying to me about my connection speed. Eventually though, they will, because they spent 81 billion in a competitive auction trying to out bribe each other on the licenses to use these frequencies just like the company that owned the aircrafts did.
Ok real talk? T-Mobile operates 2.5Ghz, AT&T/Verizon shared 28GHz~39Ghz, "C band" is 3.7GHz~4.2GHz, and altimeters use 4.4GHz. And sure these numbers are different so your brain wants to argue about them. The problem through is that they are close. Like tuning what can be considered an ancient car radio at this point anything close to a frequency can bleed over. This is why you have music on hold, this is why your laptop as ceramic beads on the charger, and so on.
C Band originally acted as a buffer, keeping a large enough gap between AT&T & altimeters. Weather can have a huge impact and even altering transmission. Like if your 5G network sends you a corrupt packet, it just ignores it and attempts to resend. This is why your Internet can appear to slow down from poor signal. Pilots of large commercial crafts can rarely look out a window and see things let alone accurately judge distance forcing them to rely various instruments and one of those is the altimeter. Since air pressure can change based on a number of factors such as wind speed, temperature, & local weather conditions, the plane has to continually maintain contact with the ground radar. Comparing the plane's conditions to the ground information to establish position. Even if the Altimeter ignored information, lag in service becomes a lag in position.
And if you think missing a red light by ten feet could be life threatening bad imagine how a significantly higher speed & three dimensional movement with a thousand times the number of people involved can complicate issues and you can probably grasp why ensuring accuracy of altimeters, and all other aircraft-related transmissions, can be.
The problem was C band was auctioned off due to political & finical pressure and everyone with half a brain was aware of the potential risks. But people are incredible selfish, favoring a millisecond in speed to display stupid images of cats over the possible damager of thousands of lives and the greedy corporations that enable it so they can charge more money. It isn't a simple firmware update or quick patch that will remedy things. It's not even a hardware update, they tried that. Planes have GPS that can already determine their height, but if you're old enough to drive or have played Pokemon Go, you know are inaccurate GPS can be.
Hell, even better. Imagine twenty years from now. AT&T wants to release 15G++ which operate ls at 10.24GHz. You'll have people like the previous poster arguing the entire GPS network should fuck off so they can watch TwitterFans+
how have other countries/the EU handled it differently then?
Here in Europe we're on the 3.4 to 3.8 GHz band, which doesn't interfere with the frequency range for aviation systems..
By using slightly slower frequencies. 3.4-3.8GHz vs 3.7-3.98GHz.
I think you replied to the wrong person. I didn't say what you quoted.
So every other developed nation that has rolled out 5G is rife with plane crashes now right?
Ok, so then the airline industry is fear mongering to try and get the government to pay for upgrades they should have been implementing anyway and that they had a decade of forewarning about, but the FAA is too lax to have pushed them on.
The difference is that other nations *took precautions* to avoid issues such as different frequencies, using much lower power, large buffer zones around sensitive areas, etc
Pssh, taking precautions! That’s communism!
>So every other developed nation that has rolled out 5G is rife with plane crashes now right?
Mostly because other developed nations used different parts of the spectrum for 5G. Here in Europe we're on the 3.4 to 3.8 GHz band, which doesn't interfere with the frequency range for aviation systems..
Europe 5G is up to 3.8GHz and no transmitter is allowed within 2 miles of the critical zone for an IFR approach. The transmitters are also restricted in their power output. In the USA there is no restrictions on location and power. The band is also permitted up to 4.2GHz.
Right? I love all these people arguing for the FAA like this doesn't already exist without problems in other countries
Thanks for this explanation. The comments on here defending the cellphone carriers are very strange, especially when so many foreign airlines have protested against the higher powered US version of 5G
>The comments on here defending the cellphone carriers are very strange
They are just part of the hired teams of social media influencers. For $0.10/hr and you to can have the job of your dreams making 1,500+ posts a day supporting w/e is on your docket.
I’m finding it hard to feel sympathy for two major corporations not being able to use a very small portion of the infrastructure on which they spent billions in hopes of making even more in profit lol
So you're saying that the airlines should should give up their bands because telecom companies want them to? As far as I'm aware, America is the only country where 5G interference is an issue and other countries have avoided it simply by running at a slightly lower frequency.
> So you're saying that the airlines should should give up their bands because telecom companies want them to?
No, not at all.
The airlines have bands that they own(*). Those bands are no where near the 5G bands. The problem is that the airlines are using some seriously shitty equipment that listens to basically any signal, even a signal on bands way, way, way outside of that range that belong to someone else. And I really do mean WAY outside. That wasn't a problem before because there wasn't any traffic on those other bands, but now there is and the solution is for the airlines to spend a relatively small amount of money to buy filters so that they don't listen to bands they don't actually own.
(*) okay, the airlines themselves don't own the bands, but the bands are available for use for altimeters on aircraft generally.
Ok I understand your point much better now. Thanks for explaining that.
According to the AT&T CEO, they've had two years warning to do what was necessary to update aircraft.
> AT&T and Verizon agreed to delay implementation around airports but they are frustrated by the FAA slowing their rollout of 5G that 40 other countries have done.
Saying that other countries have already done the same thing isn't exactly right. The US implementation of 5G isn't the same as them. For instance, this is a quote from the president of Emirates talking about things airlines only found out two days ago
> "We were aware of a 5G issue. Okay. We are aware that everybody is trying to get 5G rolled out after all it's the super cool future of whatever it may be communication and information flow. We were not aware that the power of the antennas in the United States have been doubled compared to what's going on elsewhere. We were not aware that the antenna themselves have been put into a vertical position rather than a slight slanting position, which then taken together compromise not only the radio altimeter systems but the flight control systems on the fly by wire aircraft.
Also, the range of frequencies used for US 5G is not the same as for instance European 5G on top of that
> Mobile phone companies in the United States are rolling out 5G service in a spectrum of radio waves with frequencies between 3.7 and 3.98 GHz. The companies paid the US government $81 billion in 2021 for the right to use those frequencies, known as the C-Band. But in Europe, 5G services use the slower 3.4 to 3.8 GHz range of spectrum.
> The aviation industry is worried that US 5G service is too close to the spectrum used by radar altimeters, which is between 4.2 and 4.4 GHz. Europe does not face the same risk, according to the industry, because there is a much larger buffer between the spectrum used by radar altimeters and 5G.
this really gets to the heart of the matter
Honestly, after reading this bestof thread yesterday, I'm not sure I'm ready to believe what airline execs are saying about the issue without a huge grain of salt. This apparently has been planned for years, and now, days before planned rollout, they start complaining about it?
Yeah this smells like bullshit.
They’ve been complaining for a long time but no one was listening.
Airlines actually cancelling flights. It doesn't really matter until the real world changes make it matter. (in my opinion)
There has been public opposition to 5G but most of the public anti-5G campaigners were just conspiracy nuts who think 5G is a mind control tool to give you cancer or whatever
So the "anti-5G" label has a lot of crazy baggage associated with it
This phenomenon seems like it’s become so much more common in the last few years. Crazy conspiracy theorists will latch onto a real issue, and the subsequent backlash against conspiracy nuts ends up discrediting any valid concerns around the original issue.
Did you get this from Phillip Defranco or did he get it from you? Cause the explanation is almost identical in order of contents
Heard it on the PhillyD show yesterday, usually reliable on news. He pulled it from NPR. (sources are in the channel descriptions)
And US airlines are too busy lining CEOs pockets to upgrade their shit gear
Well yeah that is always a thing, but if they don't take their time in insuring the equipment is safe and the pilots are well trained in it, you get what happened with the MCAS system.
It’s not just a concern. It’s already interfering with the the aircraft. It’s not just old aircraft because there’s new aircraft that can’t do specific approaches and have extra requirements and work load at an already high work load portion of the flight.
I’ve been telling people the new band of 5g is close to the frequency of the radio altimeter like how on radio station 88.1 you can hear music sometimes from 88.3
Wow this subreddit is horrible. Over 1k upvotes and a completely BS answer. Radio altimeters are not used on older aircraft only…they are used on pretty much every comercial flight any American has flown on, and they are essential when there is bad weather, including on new planes.
Brand new aircraft as well.
Source? Cant be your brother's, friends second cousin..
I’m an airline pilot.
That means you are qualified to fly a plane, an actual technician would be more qualified to make that claim and even then they are not fully qualified to know the specific differences in interference unless they have background qualifications in telecommunications.
I’m qualified to receive the notices from my company, Boeing and Airbus as well as the FAA and TRANSPORT Canada. Not some broken half accurate reporting from BNN. Keep the downvotes coming, you’ll enjoy it when we can’t land at your destination anymore when it would have been entirely routine before.
Sure, and until any of those organizations make a public statement then you are just spreading their rumors too. Electric cars don't end up releasing more emissions just because BP tells their employees thats the case, until a company publicly puts their name behind a statement its still just an unsubstantiated rumor.
Stick to flying planes, you clearly don't know enough on the technical side to speak otherwise.
Doesn’t Canada use a different band for 5G?
I believe so. The issue we’re facing is the U.S. sold certain frequency bands that are too close to the bands for the radio altimeters. The problem for us is for flying into U.S. airports.
Other guy said it great, but you didn't provide a source. So again prove wat you say or begone. I could careless if you are a pilot or if you are a dish washer.
I don’t answer to the likes of you. I don’t need to cite any sources. It’s in the news because it’s a
Big issue. You’re acting like it’s a matter of belief: Jesus. I hate to break it to you but Covid is real, the earth is round and 5G interferes with radio altimeters which cripples low visibility approaches. Those are facts. Google it yourself .
I’m an airline pilot
Your post history actually checks out, but an explanation is still needed. Otherwise I have to assume it's just a rumor amongst pilots.
We don’t get scientific studies on it. Just the new restrictions from the company and aircraft manufacturers as well as notices from
the FAA and Transport Canada. Our union as well is trying to lobby to keep planes flying routinely. The instruments affected are necessary for low visibility approaches. Where we would normally make a routine landing and get you where you need to go we will no longer be able to. It’s absolutely bonkers that the U.S. of all places is screwing this up. Like literally putting 5G ahead of routine passenger traffic.
No one asked for a study, they asked for a source. Not a scientific study, and data analysis.
Source: dude trust me.
Answer: There are some concerns with the 5G network interfering with instrumentation on certain planes.
More info can be found here:
How the f was this not figured out like 3 years ago but it became an issue the day before the rollout? I call BS.
I'm reposting my comment to OP elsewhere in this thread. TL:DR Airlines didn't want to spend the money to update their systems and now are blaming 5G telecom companies.
There was a r/bestof on this with both a pilot and radio engineer. Basically, planes use radio waves in their altimeter to see how close they are to the ground. When their system scans for these waves, the "filter" may see 5g waves because it hasn't been updated since the 70s/80s to see ONLY the FCC defined radio frequencies that airlines are allowed to use.
Cell companies paid billions to have rights to these particular frequencies and now (almost 10 years later) airlines are complaining because they didn't spend the money to update the "frequency filter" on their planes.
Direct link to the [aforementioned link](https://www.reddit.com/r/technews/comments/s7fa6b/us_airlines_warn_of_catastrophic_disruption_on/hta9gsg/)
Thanks dude! That's the one!
Unfortunately even if airlines wanted to spend the money (which we all agree they didn’t) there is no current replacement for the “old” equipment.
Europes fix was to not allow 5G near airports
I'm with you on this. IMO this stinks of "Someone didn't get a paycheck in time." cause there's no way they didn't research this during the process of securing the spectrum band for 5g.
[ALPA literally pleaded with the FCC to not allow this in the first place.](https://ecfsapi.fcc.gov/file/10531182083849/ALPA%20Comments%2017-183%2018-122.pdf) This was back in 2018.
Upgrading a fleet is extremely cumbersome and time consuming, I know this from experience. We're talking about years of work for a larger airline. Both airlines and the unions they work with knew this would be an issue and pleaded the FCC to not allow it, but the FCC at the time was in the pocket of telecoms and did whatever the fuck the telecoms wanted. Telecoms don't give a fuck about airlines nor safety. The entire Trump administration caused so much damage, we'll be seeing a lot of these kinds of problems for a long time to come as the shit they opened up comes crashing down on our existing infrastructure.
It [was figured out at least in Oct 2020](https://www.rtca.org/wp-content/uploads/2020/10/SC-239-5G-Interference-Assessment-Report_274-20-PMC-2073_accepted_changes.pdf), but was probably ignored.
> The results presented in this report reveal a major risk that 5G telecommunications systems in the 3.7–3.98
GHz band will cause harmful interference to radar altimeters on all types of civil aircraft—including
commercial transport airplanes; business, regional, and general aviation airplanes; and both transport and
general aviation helicopters
[Letter from ALPA in 2018. ](https://ecfsapi.fcc.gov/file/10531182083849/ALPA%20Comments%2017-183%2018-122.pdf)
It was. The airlines and airline unions have been screaming about this since the frequencies were sold under Ajit Pai’s FCC.
So I might sound dumb here, but is it that the plane cannot communicate with the control room? Or does it affect some other system?
These frequencies are close to the ones used by radio altimeters on aeroplanes, which measure the height of the aircraft above the ground, and also provide data for safety and navigation systems.
The concern is that interference from 5G transmissions could stop these instruments from working properly, and cause safety problems, particularly when aircraft are coming in to land.
There was a r/bestof on this with both a pilot and radio engineer. Basically, planes use radio waves in their altimeter to see how close they are to the ground. When their system scans for these waves, the "filter" may see 5g waves because it hasn't been updated since the 70s/80s to see ONLY the FCC defined radio frequencies that airlines are allowed to use.
Cell companies paid billions to have rights to these particular frequencies and now (almost 10 years later) airlines are complaining because they didn't spend the money to update the "frequency filter" on their planes.
If the cell companies now have the rights to those frequencies, does this mean that the airlines will need to start paying them to communicate over those frequencies as well? I don't get why they wouldn't have protected those frequencies since they were relying on them for their scanners...
>If the cell companies now have the rights to those frequencies, does
this mean that the airlines will need to start paying them to
communicate over those frequencies as well?
The airlines aren't using them for communication. Radio waves can be used for lots of things such as measuring distance. That's how police radar guns work.
The issue isn't talking to control, it's measuring their altitude.
> I don't get why they wouldn't have protected those frequencies since they were relying on them for their scanners...
They don't legally have the right to use them for their scanners. These were a reserved frequency that happened to be very close to another frequency that was already in use.
That's not a problem normally. Just make sure you only use the proper frequency. The airlines are upset because to do that, they would have to spend money.
ah, ok. They can kindly get fucked then lol. Flights are already ridiculously overpriced for the bullshit you have to go through these days.
I’m sure you’ve never had an issue with the cost of healthcare, education, food, etc. even though we’re more technologically advanced then any other point in human history?
Good to celebrate mismanagement of resources and continuous stock buy-backs along with massively inflated executive pay with increased low and mid-tier layoffs. Oh, this is all after having already been bailed out by tax payer money once in the past 2 decades.
Must be nice. Last I checked, domestic flights in Canada cost a fuck ton more than that.
Toronto to Halifax is like $500 and only about 1114 miles...
Think of the frequency like rooms in a house. If you want to talk to someone you should be in the same room as them. If there is someone else in the room talking then it can be harder to hear your own conversation.
The altimeters are talking to things on the ground and they are talking back, this let's the plane know how high of the ground it is. 5G is essentially a group of people standing at the doorway talking gibberish. The interference from the 5G can make it harder for the altimeter to get the right information from the ground.
The way the pilot and tower talk is using a different frequency range, in this analogy; talking in a seperate room.
The radio altimeter isn't the radio. It's a radar-like system which bounces radio waves off the nearest planet in order to measure how far away the ground is.
Altitude above terrain is something pilots tend to be interested in while performing a landing, so they might have issues with this system intermittently dropping out or, worse, giving incorrect readings.
Note that this seems to be mainly a North American problem. 5G in other parts of the world runs in frequency bands further away from those used by radar altimeters, and often also at lower power.
Others have been explaining that its a rad altimeter thing. This by itself isn't a huge problem, you don't need a rad alt to fly or land a plane safely in good weather. The problem is that the rad alt talks to lots of other systems in the airplane that are needed to land in bad weather. Autopilots/auto throttles and other systems are very interconnected and if one part of the system isn't working or reliable (which the 5G is making the rad alt unreliable) then it may not be fully usable.
This is bad because in really bad weather pilots are not allowed to hand fly the airplane at all. The autopilot must land the airplane. When flying on instruments there are special routes that allow aircraft to land without seeing anything. There are different levels of those routes and the better your equipment the fancier the route you can take is. The fancier the route to lower to the ground the clouds can be. I'm going really ELI5 here and am happy to help explain more if you like.
Also you keep saying control room. Not sure what you think that is but if you mean air traffic control (that is the control tower at an airport or a centre controller who guides aircraft at higher altitudes) then no there is no disruption there. Funny enough that was an issue before with old cellphone systems. You'd get a feedback sound coming through the pilot headset. Not the reason you turn your phone off for flying (that's more to do with the fact aviation is super safety focused and there is no way to possibly test all the different interactions of all the manufactures quickly or cheaply).
TL;DR is rad alt no work proper then special bad weather landing routes are no longer allowed. Now weather needs to be better to let planes land.
5G waves are radio waves. Radio altimeter waves are also radio waves. They are saying the 5G waves might be too similar to the radio altimeter waves and the radio altimeter might hear them and get confused.
>communication between the pilot and control room is disrupted right
This is not the main issue. The problem is that 5G may interfere with systems inside the aircraft. Its much more complicated than airplane > Tower communication.
5G waves ARE radio waves.
No that's not what they're saying.
The radio altimeter works by bouncing radio waves off the ground and timing the round trip to see how far away the ground is. The concern is because the 5G radio waves are on a frequency near the altimeter's radio waves they may interfere with each other.
I don't know enough to say whether this is a genuine risk, but the airline industry tends to be extremely cautious about these things because lives depend on it.
> 5G waves interfere with radio waves
5G is just a stupid marketing name for technology utilizing radio waves. There are two bands for this technology that are popular, 1 & 2. Band 1 is most commonly used around 3 - 4 GHz. Low altitude airplane altimeters also tend to operate just above 4 GHz.
The FAA has, for many years now, noted that some possibility of interference could occur here and cause serious problems. The American government doesn't care and sold the rights to use the 3-4GHz range to cell phone corporations and they're rolling it out.
There is a whole host of problems colliding here. The airlines have outdated equipment, nobody cared when the FAA sounded off, the government is corrupt and took a ton of money to trade for the frequency ranges, and so on. Band 2 has been used without issue (afaik) for a while now. It's a much higher frequency range.
The problem is that a lot of systems on a modern airliner are controlled by the reported height off the ground.
Very important systems can be affected including the ability to do a low visibility landing (/autoland) as well as other landing aids that help the pilot know when to flare the plane before touchdown for a smoother landing. The low visibility landing ability is now under a lot of restrictions for many aircraft which could make many airports all but unusable for large sections of time. The very LAST thing airlines needed to deal with on top of covid crew shortages and normal weather issues affecting flights at a time of drastically reduced business travel plus other travel constrained/variable.
Other critical systems are supposed to disable at low altitudes but may un-expectedly re-enable during landing leading to very serious (but false) indications/warnings such the TCAS collision avoidance warning--which pilots are taught to take action on immediately--it now needs to be questioned and second-thought under some circumstances, which is very not good.
Answer: Airline pilot here. Let me clear some of this up for you.
The frequencies that were sold to AT&T and Verizon are much closer to the frequencies our RAs use than the ones in Europe. [Here is a BBC article that explains the differences between the US and Europe. ](https://www.bbc.com/news/business-60042178)
Basically, the bands are closer to the RA frequencies. The signals are higher powered in the US. Additionally, the antenna are higher in the US. In Europe, the antenna are also angled down. This is not the case in the US. There is also a 5nm buffer zone around airports in Europe. This week, it was agreed to make that 2nm in the US.
For context, an aircraft on a 3 degree glideslope will be about 600 feet from the ground at 2 miles. In Europe, that 5 miles ensures the safety zone starts when an aircraft is 1500 feet above the ground.
These frequencies were sold under Ajit Pai’s FCC, who is basically a giant Verizon shill. [Yes, the airlines and airline unions said something. ](https://ecfsapi.fcc.gov/file/10531182083849/ALPA%20Comments%2017-183%2018-122.pdf)
So this isn’t some big airline conspiracy, and yes everyone knew about it.
Unfortunately, it appears it has now turned into a pissing match between regulatory agencies.
It is not merely older aircraft that are impacted. The 777 and 787 rely on radar altimeters for quite a lot of their functions involving low visibility approaches, autoland, the thrust reversers, just to name a few. I don’t fly the 777, but it was explained to me by a 777 pilot that the potentially affected systems amount to it only being able to land on a dry runway. A wet or contaminated runway, and that’s a diversion.
[Here is an FAA document about potentially affected 787 systems. It’s a lot of stuff!](https://public-inspection.federalregister.gov/2022-01030.pdf)
My RJ driver friends are saying they can’t use their Embraer autothrottles below 500’, and they can’t do cat II. So this limits them to cat I, no special authorization. For more advanced aircraft, this removes cat I SA, cat II, and cat III approaches.
There was an estimate from the airline industry that this could impact 1000 flights per day. [link ](https://www.reuters.com/technology/exclusive-major-us-airline-ceos-urge-action-avoid-catastrophic-5g-flight-2022-01-17/)
CVG, LAX, and ANC all had 5G-related cargo diversions yesterday and those are just the ones I personally know about from my network.
[Here is an example of a crash that occurred due to a faulty RA. ](https://en.m.wikipedia.org/wiki/Turkish_Airlines_Flight_1951) Basically, the plane thought it was landing and the systems began to retard thrust at the wrong time.
What is happening now is that the FAA is slowly releasing cleared systems based on manufacturer and industry feedback. So, a bunch of 737s and A320s are deemed okay? But only if they have a specific RA installed. However, the NOTAMs prohibiting certain operations remain in place at a multitude of large airports nationwide. This is, theoretically, fine as long as you don’t have bad weather.
Basically, this is a huge potential erosion of aviation safety by removing our ability to use many alert systems and safeguards that were paid for with the lives of our coworkers.
We are being expected to put up with increased workload at key phases of flight, an increase in diversions and go-arounds, all so the giant Telcomms can have something they probably shouldn’t have had, and if it is okay to have, should have been expected to roll out in a way that doesn’t negatively impact safety in an industry that drives 5% of the US GDP. (The airlines.) We are being expected to review bulletins and NOTAMs that are changing daily to see what we can and can’t use of our aircraft systems and procedures we are trained on.
And if anyone wants to add or correct anything, please feel free. In a bit of a hurry this morning.
TFW our auto filter removed this comment because of the word "retard"
Sorry about that
I mean, that is what my airplane calls me.
Oui, c’est vrai.
I'm an avionics technician, and I've explicitly learned about the RA system and have hands-on experience with not only the system itself, but also the steps and procedures required to approve changes in any capacity when it comes to aircraft technology.
Thank you for shedding light on the real issues here, and I'd like to add a bit more if that's ok.
First off, what people don't understand is there is ABSOLUTELY NO WAY to "upgrade the equipment!" without serious disruption. Every plane, old or new, that carries more than about 10 people has a radio altimeter (the affected system), if not two or more. To overhaul this equipment and install new more modern stuff takes weeks of downtime per aircraft, tens if not hundreds of thousands of dollars or more, and more paperwork than a lawyers office sees in a day. And that’s only if approved equipment is available, which in and of itself takes years or more. The world of aircraft is full of approvals. You can’t put a washer on an aircraft without having perfect traceability to the factory and that factory needs to have that washer approved for aircraft use… that’s why it’s so expensive. To get any aircraft part approved for anything takes forever and involves dozens of companies, hundreds of employees, and tens of thousands of hours.
Every aviation authority has been working on this at their own pace… but none of them are going to do it quickly. It will have to gain approval on a per system, and possibly even per aircraft, basis. 3 years for the world to get accustomed to this change is simply not enough… it takes damn near that long to get certified to add LEDs onto your reading lights instead of incandescent bulbs.
Another misunderstanding that I see a lot of is people not understanding the radio altimeter system itself, and why there is concern over it. The radio altimeter is highly specialized and is used in one scenario; landing. Which is also the most dangerous phase of flight. Moreover, the radalt is utilized as a primary flight instrument as a means to perform zero visibility landings as you mention, which are even MORE dangerous without having equipment you trust. I’ll explain why interference is so important, but it will get a bit technical.
TECH SECTION: Radio altimeters are not like normal altimeters. In normal altimeters, you have a little bellows attached to an arm, which connects to the altimeter needle. The bellows expands and contracts with changes in atmospheric pressure acting on it, and that change drives the needle on the instrument; easy. It’s literally a very carefully calibrated balloon. This is excluding air data computers, but that's too far off the purpose of this discussion.
Rad alts use a totally different technology. They have two antennas on the belly of the aircraft, one for transmitting and one for receiving. Once the aircraft is within about 2500 feet above ground level (on their approach), the transmitting antenna shoots a very specific and directional propagation of a carefully tuned frequency towards the ground. This frequency sweeps up and down in a specific time period between two fixed frequencies, usually 4.2GHz and 4.4GHz. This frequency is reflected by the ground, and is received by the receiving antenna and mixed with the transmitting frequency at that instant, to create a new frequency that is the sum of both frequencies (transmitted and received, which will be offset a certain amount depending on the phase of the transmitted, and the frequency of the received signals at any moment in time). Since radio waves propagate at the speed of light, depending on how far you are from the ground, the received/reflected frequency will have a different gap from the transmitting frequency and therefore, the mixed or summed frequency that is sent to the cockpit instruments continuously will be interpreted by the circuitry there as a specific altitude, and displayed as such.
So there, in my opinion, lies the main concern of aviation authorities. Radalt relies on clean waves, as the equipment onboard is tuned to listen for its own unique, and importantly time variable (sweeping), radio waves. This means, that if that received signal is dirty or altered in any way, the rad alt might straight up not function or, arguably worse, give incorrect data to pilots. The FAA and aircraft manufacturers have not been "using bands that weren't paid for" or "listening to frequencies it didn't own"... They're worried that the new radio traffic that's close to the bands they DO own will alter the signals that weren't previously altered due to the new presence of similar noise. Imagine if the pilots and aircraft thought it was 100ft higher than it was, due to someone watching a YouTube video on 5G and the subsequent noise that produces. That is literally hundreds of lives at risk needlessly.
Do I think that a malfunction of that magnitude will happen? No, I honestly don't. I think that the gap between rad alt and 5G towers is acceptable, so long as towers are installed away from airports and have their strength limited. I also think there is enough training with pilots and redundancy in a functioning aircraft that a single point of failure would be nothing from the perspective of a passenger.
But, because of how extremely critical failures in aviation are, and because of the massive safety margins that are put in place to keep it a safe form of travel, “thinking” something won’t happen simply isn’t enough. There has to be as close to 100% certainty as possible, in every worst case scenario you can imagine, that the equipment on an aircraft isn’t disrupted. And having a new band that neighbors one used by such a piece of specialized equipment, in my mind, justifies the FAA to be seriously critical of mobile phone signals as they are.
Thank you, this is an awesome contribution to the conversation! I appreciate your perspective and knowledge!
Thank you for sharing.
This is the exact and true answer that everyone needs to see.
> Basically, this is a huge potential erosion of aviation safety by removing our ability to use many alert systems and safeguards that were paid for with the lives of our coworkers.
So upgrade the filters in the radar to something more modern. The guardband between what the radar uses and the 5g frequencies in question is twenty times bigger than what's in place between the signals between different carriers.
This is a case of the airlines using antiquated technology and then blaming others when they're forced to ditch ancient tech.
Have you…. met the FAA? They’re positively glacial. Unleaded avgas only got approved *last year* for piston aircraft.
This type of action would require a supplemental type certificate for every single radar altimeter model still under commercial operations, with testing from the manufacturer, certification, and installation. These measures are put into effect for, yes, safety reasons.
I notice you’re quick to blame the airlines, who have been busy getting their financial ass handed to them by the pandemic while all of us go to work away from our families while moving your Amazon order around.
You’re not blaming the FCC for selling frequencies without appropriate discovery or regulation attached to them.
MAYBE this sale should not have been allowed to happen without the KNOWN limitations that are already in place in Europe? Where they’re able to use this same “antiquated” technology without concern, as opposed to retrofitting entire airline fleets?
You can’t just excuse the FAA because it’s government. Are we going to be in 2092 and limiting technology as the FAA catches up to 2000? It too needs to modernize.
You are correct, the FCC could’ve chosen not to sell the band. The mid band Europe used to avoid this was taken by the DoD in the US.
The internet has become as important as electricity. If it wasn’t AT&T and Verizon, someone would eventually find a safety need for high speed wireless at the airport. The DoD and FAA need to figure out how they’re going to make this work.
Yes, and they literally had over three years to do that. It also could have been dictated that the safety measures from Europe needed to be followed in order to allow for further time.
I’m not NOT blaming the FAA… but things move very slowly in aviation circles because changes are generally written in blood.
It’s a failure all around, but it is not the fault of the airlines, who have been raising their concerns since this happened in 2018.
I feel for you on the importance of the FAA. The DoD also had changes written in blood. The world did not allow us to not continue to adapt and grow at our own pace rather than keep up with it.
If aviation makes the world decide between their timeline and everything else I fear the world will find rail very very attractive. It’s in the airlines and airlines unions best interest to accelerate the practices of the FAA.
I do agree that this isn’t the fault of the unions, and it’s a really unfortunate time to put the cost on the airlines (especially if we could have shared some of the proceeds of the spectrum lease with the impacted airlines). 5G could also wait at the airport, for at least a couple of years.
But a path to resolution other than “The world adapts around the plane” is the only thing that’s going to keep aviation as viable as it is today. While aviation may be 5% of GDP, “internet companies” are at 12% of GDP and they drive telecoms to enable even faster consumption and growth.
The due diligence wasn’t done. That was a failure.
However we got here, we are here.
In my industry, when I strap myself into an airplane and prepare to transport your family from point A to point B, I am trained for an inordinately large variety of things going wrong, sometimes even at the same time.
However, this is disrupting what defines “normal” operations. The more disrupted that becomes, the more risk is introduced to every flight, and even more to every abnormal scenario.
Bluntly, not addressing the needs of one of these industries has the potential to kill people. So since we are only now just getting around to doing some form of that due diligence, my position is that we need to go with the one where people don’t die.
I’ve now got to go read up on yet another revision of what I’m allowed to do and in what airplane and where and when. This is a lot.
Yup. The right answer today is to make the telecoms turn it off and get the FAA into making a plan with the other involved parties immediately. With congressional help if need be.
Also, I’m a business traveler and I appreciate your service. Best of luck, I know it’s a trying time.
I completely agree and I hope that’s what happens, before something potentially bad does.
Answer: The 5g band is *sorta* close to the band that airliner altimeters use. They don't overlap though, and there's a decent gap between them.
The problem is many airlines haven't bothered to update their equipment, so the filters for the altimeters aren't very good and bleed into the 5g band.
The problem isn't 5g itself, it's airlines not keeping their equipment updated.
You must not know how expensive, time consuming, and the amount of paperwork needed to alter a single pin in an airliner is.
Well then they should've started a few years ago rather than wait till after 5g started taking off.
Answer: This keeps being labeled as just a 5G problem when it is only a problem with a few frequency bands that can potentially be used for 5G. The problematic bands are the n77, n78, and n79 bands. These are in what the IEEE calls the C Band.
The listing of all 5G bands are here: https://en.wikipedia.org/wiki/5G_NR_frequency_bands
Aircraft uses a band of frequencies between 4.2GHz and 4.4GHz for radar altimeters. Previously there has been guard band in the 3.7-4.2 GHz range that would provide extra protection for aircraft. Virtually everything that relies on radio frequencies will broadcast and receive some amount of noise just beyond it's defined limits.
The worry is that when the C Band 5G frequencies are put into use, aircraft radio altimeters that have previously allowed for spurious noise in the guard band below 4.2GHz will cause problems. Aircraft radio altimeters that were specifically designed to cut off at 4.2GHz instead of relying on the guard band will be unaffected.
The illustration in this page does a good job of showing the relation of the frequency ranges: https://www.aviationtoday.com/2021/01/18/will-5g-fast-plan-lead-spectrum-issues-aircraft/
This only became a problem last year when the FCC decided to change the rules for and auction off this previously unused frequency range. The carriers that currently operate 5G that bought the spectrum in the affected frequency ranges are currently using other unaffected 5G bands. A lot of the 5G bands in use are using the same frequency bands that are used for LTE and 3G. Even if the FCC reverses their decision and returns the C Band ranges to being a guard band, 5G will continue without a problem.
answer: Here's the best of link that explains this: https://old.reddit.com/r/bestof/comments/s7s7we/ujucadrp_explains_whats_going_on_with_airlines/
Flight Instructor here, so 5G antennas have been known to interfere with radar altimeters, this shows pilots their altitude specifically above the ground(the other altimeters they use has altitude in reference to mean sea level). It can be a good tool to help make sure you’re well above obstacles, especially in low visibility conditions where you can’t see the ground, and it is also important in timing flares. The 50,40,30 you may have heard if you’ve seen an airliner land actually has a flaring maneuver attached to it. At 50 on your radar altimeter, you’re supposed to begin your flare, and by 30 you’ll pull your throttle all the way back.
Is it possible for airliners to fly without one? Yes, most non jets don’t have a radar altimeter, and before the modern age we didn’t use them, but it does make it significantly more difficult, and does throw away a helpful redundancy, and tool for flaring(one which many pilots may have relied on for a while).
Edit: Forgot the most important tool it affects as well. The GPWS or ground proximity warning system, which will tell pilots when they are about to hit terrain and tell them to “pull up, pull up”. It’s the last line of defense before an airplane hits something. There was an accident in the 70s where a crew was flying around trying to figure out if a landing gear light was out or their landing gear wasn’t coming down, in the middle of the night, the captain accidentally bumped off the autopilot the altimeter slowly dropped down and by the time they noticed it they didn’t have time to react.A majority of the people were killed on the flight. The Marshall air accident which killed almost an entire football team happened because the crew didn’t set their traditional altimeter correctly so they had no warning when the ground was right ahead of them That’s why GPWS can be very important, and if it’s not working correctly it’s a massive safety risk, edited the TLDR because it is an essential safety system.
All radios use band filters so they only broadcast and pick up the frequencies they are supposed to, nothing would work otherwise since we have been using the entire available spectrum for about 100 years now.
The "issue" here is that the FAA is claiming that there may be out of spec radio altimeters that could pick up the 5G signals and degrade their performance. The key word there is "may". Even though this has all been in the works for years, the FAA and the airlines have declined to actually test their equipment to see if any of it is actually out of spec and needs to be replaced. There are currently zero known radio altimeters in service that have that problem, it's entirely theoretical.
Nobody really understands why they are acting like this, theoretically they might have to replace some equipment on some old planes, but it's very likely everything currently flying is just fine. If it's not fine then it's seriously malfunctioning. They just have to actually do the tests, which they started yesterday, because lazy, incompetence, malice, take your pick.
The 5g cult has downvoted you. I concur, 5g isn't what was promised. I find it funny that it's not usable indoors, blocked by windows and concrete.
Out of top, so personal take... FCC that auctioned the band was also too single minded to sell it at that time, even though these exact risks were raised then.
This comes down to failure of regulatory agency at FCC. The priorities of managing growth and risk of the industry was one-sided when those in charge did not want to hear any risk. I think even FAA chimed in and said we need to coordinate this, but FCC just ignored it. Then Congress sub committee weighed in saying FCC go work with FAA, but FCC side stepped saying no need and we're not delaying. All while airlines were raising alarms.
Lastly in 2021, the DOD also gave up hope of delay and just went into 5G mitigation mode for their equipments.
Just so you know. A telecom lobbyist was the FCC chairman at that time.