Way back in ancient history, Airlines prohibited the use of Cellphones out of the fear they’d affect the pilots instruments…part of it was that the planes were much older than the technology, and after time it came out that a secondary reason was to keep the passengers aware during takeoffs and landings, additionally, cellphones at altitude could see multiple cell towers and affect resources and hand-off negatively…Now (decades into it), bluetooth and Wi-Fi are a-ok, and pretty much as soon as rubber touches tarmack, the airplane mode’s off, and it’s business as usual.
Until the vaccines affected our 5g’s apparently.
Cellphone companiess have taken over new frequencies, and are looking to improve cellphone reception (or just cram more paying devices into more of the radio spectrum) and now the Airlines sound like anti-vaxers.
In the meantime, we’ve gotten a WHOLE lot better at understanding radio reception and transmission (insert pictured of anechoic chambers and phones rubberbanded to dummy heads with wires coming out of them) and I find it VERY hard to believe a modern cellphone could, in any way, affect modern avionics, assuming those manufactorers have been as diligent in testing as the cellphone folks.
So what’s with the pissing match between the airline and cellphone industries, and is it really ‘we’re afraid 5g will cause our planes to fall out of the sky’?
As I understand it, the potential problem is not with passengers using their 5G cellphones on the flight, it’s with 5G towers near the airport possibly interfering with the plane’s communication systems as they come in for a landing.
There is concern about the possibility of 5G signals interfering with commercial aircraft radar altimeters.
From what I saw on the news last night, there are a number of specific US airports where this is expected to be a concern because of the placement of 5G cell towers relative to landing approach paths. AIUI, the problem is less about safety and more about operational disruption. If your radar altimeter can’t be trusted at a particular airport, then you won’t be able to land there in certain kinds of weather and you’ll have to divert to your alternate airport, incurring extra costs for the airline and extra hassle for the passengers.
It’s not just the airlines saying there’s a problem, it’s the airplane manufacturers:
“Multiple modern safety systems on aircraft will be deemed unusable,” according to the letter, which carried the letterhead of Airlines for America, an industry group. “Airplane manufacturers have informed us that there are huge swaths of the operating fleet that may need to be indefinitely grounded,” stranding thousands of passengers and worsening turmoil in the supply chain, the airlines said.
So 5g us moving into the UHF range…which was always in use (and I’m assuming) wasn’t an issue as that used to be a point source on some high ground somewhere, and is now near the runways.
At the same time, flying is ALL ABOUT redundant control systems and areas they can’t fly and GPS mapping and…I’m just wondering if something happend to also remove the redundancies (atmospheric measurement for altitude, GPS calculation of altitude…is there an inertial component to all of this or is that reserved for missles and military aircraft?)
To be honest, this is still a concern, but pragmatism wins out - people just weren’t going to follow this policy and trying to enforce it was not going to be practical. I guarantee somebody on most flights either won’t or will forget to put their phone in airplane mode. We know these devices have effects on aircraft systems but, for obvious reasons, we don’t have a solid idea of just how much. So, instead of trying to enforce an unenforceable policy, the real-world solution is to have people shut off big emitters for the entirety of flights and allow lower power devices only. This trades off a bit of safety but people are much more likely to follow it.
Does this mean planes falling out of the sky? Of course not (or we’d be seeing it every day). What it means is that the level of safety we will trade for the ability to have our phones on during a flight is somewhere around one potential life-threatening issue across several tens of thousands of flights and increased load on electronics and personnel who have to deal with anything that pops up. People’s actual tolerance for risk may be lower but, if the last couple years have shown us anything, it’s that our (collectively anyway) grasp of statistics is very poor.
Radar altimeters are a critical component of the autoland function. GPS/ILS is probably fine for most of the approach, but for knowing when to idle the engines and flare just before touchdown, it’s hard to beat the radar altimeter. Multiple radar altimeters are employed for redundancy, but, AIUI, autoland systems depend exclusively on those for the final seconds before touchdown. Not a problem if the pilot is manually putting the plane down in good weather, but if it’s CAT IIIC conditions, and you don’t have autoland available because your radar altimeters aren’t working, then you have to divert.
Thanks for this, that’s very helpful. I’m just surprised at the lack of nuance…2 miles from the airport isn’t that big a deal, esp with the rest of the available spectrum…
AIUI, other countries have installed 5G towers near airports with no ill effects. Are they just lucky, or is someone overreacting to a possible threat that doesn’t really exist? This issue should be scientifically provable, but the evidence apparently isn’t 100% convincing.
Where? Maybe it’s OK for smaller airports? Maybe the 5G towers are lower power? If you could share some details, maybe one of the experts in this thread could explain why it’s OK there but not somewhere else.
Even in the US, it’s approved for smaller airports, I think.
According to this Bloomberg Report, it’s behind a paywall, you’re right. They have lower power 5G towers in Europe than in the US, so the risk is less or non-existent.
The US is using a 5G frequency band that is much closer to the radar altimeter band so there is a greater risk of interference.
From here:
There is no single part of the electromagnetic spectrum that 5G occupies. Some countries are using 600 megahertz to 900 megahertz, which isn’t dissimilar to 4G. Some are placing it between 2.3 gigahertz and 4.7 gigahertz, which boosts data speed somewhat. And others are using 24 gigahertz to 47 gigahertz, which requires more towers but offers even higher data speeds. In many cases a network will use a mix of these. In the US, the frequencies allocated for 5G are closer to those used by aircraft than those allocated by the EU.
This is mainly nitpicking, but I find it annoying that the problems are being associated with 5G. 5G doesn’t directly have anything to do with this. 3G, 4G, 5G–really any of them–can work on any of these frequencies. It just happens that 5G is better able to use wider swaths of spectrum, and thus driven up demand for spectrum at higher frequencies (which tends to be less useful due to various interference effects, and thus has less competition). This particular frequency band happens to be adjacent to the radio altimeter band, but other frequencies are fine.
I find it ridiculous that the FAA has apparently been able to hold onto 600 MHz of valuable spectrum right in the microwave range, just so that they don’t have to replace some janky-ass altimeters that apparently can’t reject interference from hundreds of megahertz away. This spectrum isn’t just worth billions of dollars to telcos–it’s worth many billions to society. Radio spectrum is an incredibly valuable resource and the airlines are wasting it compared to other uses (like wasting water on almond trees instead of computer chip fabs).
I kinda does…this rollout is using UHF band frequencies, purchased by the cellphone carriers or a Whole Lotta Moolah. 4g/LTE and earlier standards didn’t use these frequencies.
I believe you’re right, the restrictions they’re talking about here are only for some airports - I assume it’s some of the largest, busiest ones, and certainly just those that have Cat III landing ability.
I also saw yesterday the power for the 5G systems in the United States is twice as much as what’s used in Europe, so there’s not a direct comparison between how US and European airports are dealing with it.
Now, as a former air traffic controller - although at a smaller airport that did not have Cat III ability - a lot of what I’m hearing from the airline side seems way overblown. Foreign airlines canceling flights to the US? I see they’re doing that, but I’m not sure why (although they’d be limited as to which airports they can actually land at, so I guess that’s a factor). Airlines warning of massive delays and widespread grounding of aircraft? I’m skeptical … the radar altimeter info is only required for approaches in the worst-of-the-worst weather/visibility conditions. Might some aircraft be unable to land at their destination during a snowstorm, if they could not trust the radar altimeter? Yes, but they’re required to have an alternate destination anyway. And if weather conditions are better than a half-mile of visibility or the cloud ceilings aren’t right at the bottom, the minimums for approaches would still permit operations, in most cases.
So it appears to be a bit of a hysterical and overblown reaction from the airlines - you’d have temporary delays at certain airports during certain weather conditions, but it’s not a wide scale disruption of air traffic across the entire country … even if this 5G interference turns out to be an issue, which no one seems to be certain of anyway.
This is what baffles me, though. It’s not like airlines and cell carriers are in competition. There’s no reason for them to overhype the danger. If anything, airlines would want 5G service at airports, because it makes the traveler’s experience just that much better.
If it only affects landings during those severe weather conditions, then maybe the airports could have a shut off switch for the 5G service when that’s needed.
