5G FCC and American Airport Drama

ethernet

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Emirates suspends US destinations​

Dubai's Emirates airline announced it would suspend flights to several destinations in the United States as of January 19 until further notice because of concerns over 5G mobile deployment.

There is a sizeable gap on the radio-frequency spectrum between the 5G networks in question, which operate between 3.7 and 3.98Ghz, and the altimeters, which use frequencies between 4.2 and 4.4Ghz.


With New 5G Delays, Can the FCC Be Trusted? FCC

Why is this this nonsense going on?

I have weak RF knowledge, but at these frequencies everything is SDR or PLL on a chip, laser trimmed resonators, cut to parts per million. Even coughpy budget 5G phones will not be spewing interference at 4.2Ghz. Spectrum analyzer 'Fails' should see any failed brands blacklisted forever. FCC's job is to 'nick' faulty spectrum polluters, super hard. A band pass or notch filter should already be on aircraft altimeters. I imagine the RF horn also points downwards. Normally the innards are in a shielded box (trying to remove mixer and harmonic whinge whinge talk).

So it boils down to naming and shaming the names and models of altimeters that are cough, and known to lack robust design. I suspect most 30yo gear would pass, but to be sure test the telcos 5G equipment at extreme temperature ranges (thermal drift) at 100% load.

There are some reports that all these C-band reflections, light up claimed stealth fighters and or could be used to be a passive radar, or that passengers could also geo-locate in 3D and ask why are we in circuit etc.
 

jrfsp

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Will QFs 787s have any issues with flying the 787s to the US with the 5G stuff going on?
 

Mattg

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What a bizarre situation. And it's not just Emirates - ANA, JAL and SQ have also cancelled some flights to the US.
 

jrfsp

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What a bizarre situation. And it's not just Emirates - ANA, JAL and SQ have also cancelled some flights to the US.

BA is also swapping out boeing aircraft for airbus on certain US routes, which dont seem to have the issue
 

SYD

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The FCC are licensing (for $$$) more bandwidth for 5G than most countries. In theory, there’s a buffer but it seems to be one big pissing competition between FCC and FAA.

$$$ v safety. What could possibly go wrong?
 
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jpp42

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Will QFs 787s have any issues with flying the 787s to the US with the 5G stuff going on?

Is LAX the only US port operating now? I think it means that if the forecast for LAX is such that radio altimeter might be required (CAT II/III ILS), they would have to carry an alternate with a better forecast. Would be interesting to hear clarification from a pilot, but I suppose it would be whatever the normal rules are for a plane with radio altimeters unserviceable. Given QF11 currently arrives LAX in the afternoon when fog is unlikely, I suspect the chance of any impact will be minimal, as the weather in LAX is otherwise typically benign. I don't think the problem impacts takeoff since it's only the radio altimeter that's affected (open to correction on this of course).

The whole thing is a bit interesting since it seems the FAA does not have any data that shows interference is possible, and the FCC has clearly shown that there is enough gap between the 5G frequencies and the RA frequencies to avoid interference. I don't understand why the FAA has taken this approach, but I understand why airlines and pilots will be conservative about it until the FAA is happy.
 

jrfsp

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Is LAX the only US port operating now? I think it means that if the forecast for LAX is such that radio altimeter might be required (CAT II/III ILS), they would have to carry an alternate with a better forecast. Would be interesting to hear clarification from a pilot, but I suppose it would be whatever the normal rules are for a plane with radio altimeters unserviceable. Given QF11 currently arrives LAX in the afternoon when fog is unlikely, I suspect the chance of any impact will be minimal, as the weather in LAX is otherwise typically benign. I don't think the problem impacts takeoff since it's only the radio altimeter that's affected (open to correction on this of course).

The whole thing is a bit interesting since it seems the FAA does not have any data that shows interference is possible, and the FCC has clearly shown that there is enough gap between the 5G frequencies and the RA frequencies to avoid interference. I don't understand why the FAA has taken this approach, but I understand why airlines and pilots will be conservative about it until the FAA is happy.

It seems a crazy situation, thats correct only LAX on (QF), UA are also operating to SFO.


"5G C-Band interference which may affect multiple airplane systems using radio altimeter data, regardless of the approach type or weather. These anomalies may not be evident until the airplane is at low altitude during approach. During landing, this interference could prevent proper transition from AIR to GROUND mode, which may have multiple effects. As a result, lack of thrust reverser and speedbrake deployment and increased idle thrust may occur; and brakes may be the only means to slow the airplane. Therefore, the presence of 5G C-Band interference can result in degraded deceleration performance, increased landing distance, and runway excursion."
 

jb747

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Will QFs 787s have any issues with flying the 787s to the US with the 5G stuff going on?
I don’t know that it would only be the 787. As far as I know, all radalts work in the same frequency band, which means it would affect all aircraft that use them.
Is LAX the only US port operating now? I think it means that if the forecast for LAX is such that radio altimeter might be required (CAT II/III ILS), they would have to carry an alternate with a better forecast. Would be interesting to hear clarification from a pilot, but I suppose it would be whatever the normal rules are for a plane with radio altimeters unserviceable. Given QF11 currently arrives LAX in the afternoon when fog is unlikely, I suspect the chance of any impact will be minimal, as the weather in LAX is otherwise typically benign.
It means that Cat II/III would not be available at all. Basically as if they’d never invented it.

Even now, if it’s forecast, you still need an alternate which as better conditions, but you can at least try the approach, and realistically, you’re about 99% certain of getting in. With this, you would not be able to have a go at all. That’s a dramatic reduction in capability.

Beyond that though, the rad alt affects the way the aircraft fly. In the case of all of the FBW aircraft, radalt readings are used to change system modes. For instance, in Airbus, at 100’ RA the FBW system changes to landing mode, which has the effect of making the behaviour in pitch something that you can actually flare. If it stayed in normal mode, it would be very difficult to get a decent landing, and potentially quite dangerous. This has nothing to do with the weather, and is simply system behaviour during all landings.
 

NM

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There appears to be more politics than science at play in this.

Looks like someone who designs, gets approved, and sells a radio altimeter with a decent receiver filter stands to make a lot of money. 5G C-Band (3700-3980MHz in the USA) and RA operations (4200-4400MHz) should be able to share the same air space without causing any interference between each other.

Or is this just another way for conspiracy theorists to blame 5G for things they know nothing about?
 

Melburnian1

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From 'The Oz' an hour ago:

"Qantas is satisfied it remains safe to fly to the US in Boeing 787s and A380s, amid a growing furore over potential interference with some aircraft from the 5G wireless network rollout.
Several other airlines, including Emirates, Air India, All Nippon Airways, Japan Airlines and Korean Air, have cancelled some US services or adjusted schedules following a warning from the regulator, the Federal Aviation Administration.

The FAA advised that the 5G network could potentially interfere with height readings that are critical in bad weather landings.

The problem stems from the fact a segment of the airwaves being used by American telecommunications companies for 5G is too close to that used by radio altimeters that measure an aircraft’s clearance height over terrain.

Boeing 777s appear most susceptible to the issue, although a warning was also issued for Boeing 787-9s.

Qantas does not operate any 777s but does use 787s on its US service from Sydney to Los Angeles, as well as the Airbus A380.

It’s understood Qantas has no plans to change its schedule into the US at this point, but would take extra precautions, such as carrying more fuel on 787.s..."
 

RichardMEL

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seeing varying reports on this. I've seen it only affects 748, 777 and 787 but seems odd. As jb notes all of them should be on the same frequency so I am not sure why airbus products, for example, would not be affected.

It also seems odd that it's just the US operators who want t use this specific frequency band causing the issues while the rest of the world seems fine with other bands. Strange. I am reminded of when (it may still be?) that gsm in Japan was on a different system or frequency to everywhere else and that caused a bit of fun and games (I am sure someone can correct me on that detail).

Definitely interesting times.
 

ethernet

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Light RF reading, no particular order
https://www.ijser.org/researchpaper...n-Resonator-filter-for-C-Band-Application.pdf

I recall Mobile phone bandwidth was also sold off, and the Satellite man said good, the new lnb's have a filter against mobile noise. Maybe they got some duff readings because this guy moved next door Audio modulated microwave magnetron. F111 radar would also cause damage - it was the best!
I would guess RA susceptible would be about 1975 vintage. Lilke Plessey AR-3D - Wikipedia .
 

N860CR

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Maybe JB or somebody can correct me… but I’d have assumed a radio altimeter wouldn’t be a required dispatch item provided an auto land or the like isn’t needed?
 

Scarlett

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There is a sizeable gap on the radio-frequency spectrum between the 5G networks in question, which operate between 3.7 and 3.98Ghz, and the altimeters, which use frequencies between 4.2 and 4.4Ghz.
With New 5G Delays, Can the FCC Be Trusted? FCC

Why is this this nonsense going on?

I have weak RF knowledge, but at these frequencies everything is SDR or PLL on a chip, laser trimmed resonators, cut to parts per million. Even coughpy budget 5G phones will not be spewing interference at 4.2Ghz. Spectrum analyzer 'Fails' should see any failed brands blacklisted forever. FCC's job is to 'nick' faulty spectrum polluters, super hard. A band pass or notch filter should already be on aircraft altimeters. I imagine the RF horn also points downwards. Normally the innards are in a shielded box (trying to remove mixer and harmonic whinge whinge talk).
I love it: “I have weak RF knowledge…” and then proceed to spew a bunch of stuff that sounds like it’s come straight from Stimo’s!
👍

You can all find a copy here if you really need to derive the radar range equation from first principles:
😵‍💫😴
 

RooFlyer

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Maybe JB or somebody can correct me… but I’d have assumed a radio altimeter wouldn’t be a required dispatch item provided an auto land or the like isn’t needed?

There's been some discussion in the 'Ask the Pilot' thread:

 

jpp42

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It also seems odd that it's just the US operators who want t use this specific frequency band causing the issues while the rest of the world seems fine with other bands.

This part at least I understand, it's because the US frequency band for 5G is closer to the band used for radio altimeters. In places like Australia, the bands are much further apart so interference is unlikely.

Here's an article that explains why the 787 has more issues, due to higher reliance on radio altimeters for many functions: Does The 787 Have A Problem With 5G Interference? - Mentour Pilot
 

RichardMEL

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I understand that the Cband that is being used for this "enhanced" 5G or whatever they call it in the US is very close to the altimeter one, but my query is more about why is that band where it is when nobody else in the world seems to want to or need to use that specific range. That was more my point :)
 

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