I have to agree wholeheartedly. Seems more of a fight over frequency ownership than anything else.
Boeing & Airbus Afraid of 5G
- Thread starter frank candor
- Start date
I think we are saying the same thing. I said “potential”, yours is much more elegant
I’m more of a tin can to tin can with string guy. This certainly isn’t the only issue we face in the rapid growth of wireless everywhere. If someone is worried about a plane crashing that has a trained pilot aboard when the landing aids fail due to “wireless interference” imagine a delicate parts surgery by a robot controlled over 5G!
A close relative of mine worked for a high tech hardware and software company that does a lot of different kinds of work for various governments, including the U.S. That company was only one of many doing (among other things) contract work involving data gathering from all imaginable sources ... phone systems, internet, cameras, etc. ... and had an entire organization devoted to such things. ALL of those systems can be hacked if you have the resources. I'm about as far from a conspiracy crank as you can get, but as you say we'd all be pretty surprised if we knew just how much is possible. The difference between the U.S. and China might ... might ... be to the extent that such measures are broadly used, but for certain the capability for it in the U.S. is not lacking.
What do those concerns have to do with the interference problem with radio altimeters?
I've touched on this kind of thing (cross-band interference) while doing some telecoms work at Heathrow. It comes across as something of a black art with a lot of arcane terminology, but the underlying physics is solid and well understood so if the mathematical modelling says there may be a problem then it's almost certainly correct.
The extent of that problem will depend on a *lot* of external factors though, so quantifying it might be a little less precise - the same kind of problem as with predicting the weather, only without same scale of supercomputers to throw it. That seems to be about where we are now; there's probably a very valid concern, but to try and quantify it accurately would require quite specific data for a given location rather than the more general data that is being sought, so there's something of an impasse.
As you might expect, the airline industry is all over anything that might potentially cause EM interference, especially in the vicinity of airfields where they have all the risks of take off, landing, and a lot of aircraft manouvering in close proximity to manage. In our case, the primary concern over the systems we were installing at LHR was with the ground and low-altitude radar systems, where there had to be essentially ZERO possibility of any interference, but we needed to more generally assure against a lot of other systems as well.
A scenario with possible interference with altimeters? Yeah, I can see how that would be a concern for them, especially if the local climate means pilots might have to heavily rely on instruments when making an approaches in adverse weather. Put it this way; would you want to be on an aircraft making a final approach when the pilots are not certain how far below the aircraft the runway is? Even if the worst case is only an uptick in rough landings, that's still going to put more wear and tear on landing gear, increase maintenance costs, and just maybe introduce the possibility of a mechanical failure at just the wrong moment.
Ultimately though this is a cost vs. safety debate, and I think we all know how those usually end, but
after MCAS I think the aviation industry can't afford another passenger safety issue and is going to fight this long and hard. I don't think this dispute will be over anytime soon.
The extent of that problem will depend on a *lot* of external factors though, so quantifying it might be a little less precise - the same kind of problem as with predicting the weather, only without same scale of supercomputers to throw it. That seems to be about where we are now; there's probably a very valid concern, but to try and quantify it accurately would require quite specific data for a given location rather than the more general data that is being sought, so there's something of an impasse.
As you might expect, the airline industry is all over anything that might potentially cause EM interference, especially in the vicinity of airfields where they have all the risks of take off, landing, and a lot of aircraft manouvering in close proximity to manage. In our case, the primary concern over the systems we were installing at LHR was with the ground and low-altitude radar systems, where there had to be essentially ZERO possibility of any interference, but we needed to more generally assure against a lot of other systems as well.
A scenario with possible interference with altimeters? Yeah, I can see how that would be a concern for them, especially if the local climate means pilots might have to heavily rely on instruments when making an approaches in adverse weather. Put it this way; would you want to be on an aircraft making a final approach when the pilots are not certain how far below the aircraft the runway is? Even if the worst case is only an uptick in rough landings, that's still going to put more wear and tear on landing gear, increase maintenance costs, and just maybe introduce the possibility of a mechanical failure at just the wrong moment.
Ultimately though this is a cost vs. safety debate, and I think we all know how those usually end, but
after MCAS I think the aviation industry can't afford another passenger safety issue and is going to fight this long and hard. I don't think this dispute will be over anytime soon.
My issue isn't with the physics or the RF modeling itself - it's with the assumptions made regarding the level of out-of-band emissions. They don't appear to have used actual measurements of those. This is in contrast to recent GPS interference concerns which were explored by testing.
Long time pilot and current commercial airline pilot.
Several have touched on the actual issue and it simply boils down to the recently approved 5G frequency spectrum is adjacent to the radio altimeter frequencies used in airplanes. They use the radio altimeter to calculate the actual height above the ground (AGL/AFE). Generally speaking, airplanes use a standard plane - Mean Sea Level (MSL) for calculating and standardizing altitudes. AGL/AFE largely comes into play for precision landings during low visibility/low ceiling approaches. We do reference AGL/AFE for all landings, but it isn't a crucial item when we can see the runway environment.
There is concern there could be interference between the adjacent radio spectrum frequencies. I am not really sure why there hasn't been any testing done in this area and the current plan is that airports with these active towers nearby will have NOTAMS (Notices to Airmen) published that will limit reliance on the radio altimeter. During most weather conditions, this won't impact operations substantially.
But, with low ceilings and low visibility, reliance on the radio altimeter becomes crucial and in some instances is a required operational item to conduct the approach and is tightly integrated in the autopilot system. During some approaches and landings with really low ceilings/visibility, it is entirely accomplished using the autopilot. During these, the radio altimeter is a crucial part of the inputs that determine when trimming the flight controls for landing, the throttle begins reducing to idle for landing, etc. This is why Boeing & Airbus are putting out warnings - the radio altimeter is tightly integrated in the autopilot system for approaches and landings.
It's hard to fathom (just kidding, this is the US Government after all) given that the spectrum goes live in just days that there hasn't been extensive real world testing done with these towers and aircraft to determine what, if any, are the potential interference risks. Everything I have read on the topic has been based on the potential for interference due to the adjacent frequencies. I haven't seen any actual data. Doesn't mean it hasn't been done, just haven't seen it.
Several have touched on the actual issue and it simply boils down to the recently approved 5G frequency spectrum is adjacent to the radio altimeter frequencies used in airplanes. They use the radio altimeter to calculate the actual height above the ground (AGL/AFE). Generally speaking, airplanes use a standard plane - Mean Sea Level (MSL) for calculating and standardizing altitudes. AGL/AFE largely comes into play for precision landings during low visibility/low ceiling approaches. We do reference AGL/AFE for all landings, but it isn't a crucial item when we can see the runway environment.
There is concern there could be interference between the adjacent radio spectrum frequencies. I am not really sure why there hasn't been any testing done in this area and the current plan is that airports with these active towers nearby will have NOTAMS (Notices to Airmen) published that will limit reliance on the radio altimeter. During most weather conditions, this won't impact operations substantially.
But, with low ceilings and low visibility, reliance on the radio altimeter becomes crucial and in some instances is a required operational item to conduct the approach and is tightly integrated in the autopilot system. During some approaches and landings with really low ceilings/visibility, it is entirely accomplished using the autopilot. During these, the radio altimeter is a crucial part of the inputs that determine when trimming the flight controls for landing, the throttle begins reducing to idle for landing, etc. This is why Boeing & Airbus are putting out warnings - the radio altimeter is tightly integrated in the autopilot system for approaches and landings.
It's hard to fathom (just kidding, this is the US Government after all) given that the spectrum goes live in just days that there hasn't been extensive real world testing done with these towers and aircraft to determine what, if any, are the potential interference risks. Everything I have read on the topic has been based on the potential for interference due to the adjacent frequencies. I haven't seen any actual data. Doesn't mean it hasn't been done, just haven't seen it.
This letter to the FCC from AT&T and Verizon includes some interesting references that argue the same point - that the FAA stance is based on overly conservative assumptions, out of line with the rest of the world, and inconsistent with the lack of problems with existing installations:
Also, a shorter summary:
arstechnica.com
Also, a shorter summary:
FAA forced delay in 5G rollout despite having no proof of harm to aviation
US delays even as 40 countries use C-band with no reports of harm to altimeters.
arstechnica.com
While I do question quite a bit of what our government does and certainly view a bunch with a great deal of skepticism, I think would would have seen "real world" manifestations of the concerns by now. Verizon started 5G service as early as 2018 in certain areas. It's not like widespread implementation starts on Jan. 2nd. January is more the projected shutdown window of the 3G services.
Like I said I trust the government about as far as I can throw DC and this is just my opinion and it's likely worth what anyone here paid for it.
And Merry Christmas to all.
Sorry i'm kind of a luddite lurker, i found it On the BBC, So Hilarious, mankind, the Stupidest Monkey!!
TS_Thomas02
Well-Known Member
If I may provide a little input here. There’s no way that it would affect internal systems or even GPS, so, as probably presented by the mainstream media, it seems absurd on its face. As a pilot, I’m an end user of the equipment, but I can tell you what I’ve been told about interference, not as much about specs. The media often doesn’t get these details fully out to the public, so here’s what Paul Harvey used to call, “The rest of the story.”Boeing and Airbus are worried that 5G will disrupt aircraft electronics !
The FCC issued permission for the cellular carriers to start using the C-band 3.7-3.98 GHz for 5G on January 5th. All the airliners out there use radar altimeters for the final approach altitude measurement from 2,500 ft down to touchdown. It triggers certain things leading up to the landing. Especially the last 50ft. I can’t absolutely say what range my RADALTs operated in so……from what I’m told, those are operating around 4.1 GHz, (can’t find the email that had the exact number right now). The concern is that they do not want any 5G towers radiating along the final approach corridors leading up to a runway, and they want a validation that there is no signal “bleed over“ or interference but we really don’t know until we try it. So that necessarily puts us in a bit of a cautious “see what happens” mode where we have to be ready to revert some towers to non-5G or relocate those facilities IF a problem is detected.
It’s not like they’re advocating no 5G at all. Just where they put the towers.
So if we’re in visual conditions, and the RADALT gives some whacko information, we’d land just fine. But somebody’s going to want a report about it so we can get the cellular antenna moved. If it’s instrument conditions, it might mean a go-around, which we’d like to keep to a minimum.
Speaking of GHz interference: For what it’s worth, if you use a Mavic Mini (Wi-Fi) to get close up in-flight pictures of a Mavic Air-2 (Occu-Sync 2) the Mini will protest about signal interference until it just gives up and lands without warning. But up to that point, you can get cool pictures of your drones with scenery under them!
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That’s nonsense. The spectrum problem precedes Trump and most in govt that deal with this stuff are screwing over the American DoD by selling off parts of the spectrum that numerous military systems are built on. It’s no easy thing to “just move to another frequency”, but that’s how these goobers treat it.
Will 5G mean airplanes falling from the sky?
The recent 5G altimeter interference concern is an all-to-common teething problem with new technology, Tom Wheeler writes. More generally, it highlights the need for a unified national spectrum plan, another place where the Biden Administration needs to repair damage from the Trump Administration.www.brookings.edu
Thanks @sar104 for a good read. When I saw the frequencies being used I was really wondering where interference would come from except right at the 4.2 GHz cutoff, then read about the 220MHz guard band and that pretty much kills any bleed over in the primary and secondary side lobes. Interference from harmonics are pretty much impossible, but the strength of any from both that would interfere would be negligible and attenuated even further in bad weather where the radar altimeters become more important.This letter to the FCC from AT&T and Verizon includes some interesting references that argue the same point - that the FAA stance is based on overly conservative assumptions, out of line with the rest of the world, and inconsistent with the lack of problems with existing installations:
Also, a shorter summary:
FAA forced delay in 5G rollout despite having no proof of harm to aviation
US delays even as 40 countries use C-band with no reports of harm to altimeters.
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If there were going to be a problem, I would presume that it would require towers to be installed near operating runways to cause a problem.
Purely speculating (aka rectal extraction), but I suspect installing towers near airports isn't where the 5G was initially deployed and thus not a problem yet.....if it were going to be a problem.
Considering I've seen the announcement that the FAA would issue the NOTAMs where the towers posed "a threat" and that I haven't seen one of those NOTAMs yet, guessing towers aren't currently operating near the larger airports with commercial services. It's possible that the NOTAMs may be out there for smaller airports with commercial services or those serving just GA aircraft.
I don't think the real story is about interference ... the real story is why wasn't this ever thoroughly tested so as to preclude the point we have reached where the FAA will issue NOTAMs that restrict certain operations that require the radar altimeter. It's not like 5G deployment just suddenly snuck up and happened. The FCC approved it. The FAA is concerned. The makers of the autopilot systems are concerned. The right solution is to test the theory under controlled and safe circumstances.
Guessing the chance of interference is low. Problem is that under the right circumstances, the extremely rare chance could be fatal under the right set of circumstances.
Similar clash about a different “service” that could “potentially” be affected. Found out about this as there were a lot of sailors I know concerned about their ability to safely navigate. GPS is used in countless ways.
Finite resource of frequencies - infinite demand for those resources. Conflict is going to happen.
Several years old now and I don’t know if it is resolved.
Finite resource of frequencies - infinite demand for those resources. Conflict is going to happen.
Several years old now and I don’t know if it is resolved.
GPS.gov: Ligado Networks and GPS
Information about potential interference to GPS users from the LightSquared communications network
www.gps.gov
Not completely accurate.
For Category II/III approaches (low visibility and/or low ceilings[less than 200']), inputs from the radar altimeter tell the autopilot when to start reducing the throttles to idle for landing as well pitching the nose up in preparation for landing. There are other flight control inputs, but those are two of the bigger ones I think.
Imagine the jet being a few hundred feet up and suddenly think that the runway is approaching so that it starts reducing power and flaring. Pilots are probably suddenly wondering - WTH? The runway wasn't that close just a moment ago. Do they connect the dots quick enough between barometric altitude, radio altitude and field elevation? They probably do. But they might not.
I am not saying these are likely events, but just pointing out how radar altimeter readings directly impact engine and flight control inputs.
Spot on in both cases. The radar altimeter is not all that crucial for visual approaches or even Category I (ILS/RNP) approaches.
I agree that this is the media, not knowing what they are talking about, using sensationalism to drive clicks and eyeballs.
As you pointed out, this is about potential frequency bleed over that inadvertently spoofs a radar altimeter while a jet is landing under low visibility and/or really low ceilings.
I'm not clear how you came to that conclusion, since the media articles linked in this thread are simply reporting on the FAA statements on the subject. Where is the sensationalism that you refer to?
Juan Bianco (airline pilot) did a report on this subject a month ago before the media started to report on this. The description also contains links to techmical papers that have been warning for some time about the danger of having 5G towers near the approach path of planes.
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