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kalvado
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Re: FAA to prohibit many flight operations due to risk of ‘5G’ wireless interference

Fri Jan 21, 2022 8:22 pm

DLPMMM wrote:
This seems very drawn out and complicated for something that should be able to be fixed with a simple band pass filter on the receiver.

Bureaucratic vs engineering approach. Guess which one is native to FAA.
 
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Revelation
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Re: FAA to prohibit many flight operations due to risk of ‘5G’ wireless interference

Fri Jan 21, 2022 8:31 pm

kalvado wrote:
Chemist wrote:
Somebody please explain to me how hardware approval can be safe enough for a temporary time period, but not safe enough for an indefinite time period.

This reminds me of how Boeing thought the MAX would be safe enough after crash #1 until their software patches would be available.

Risk management. if they estimate <0.01 crash over the month for the fleet, then it is not too bad. If that is allowed to hold for 100 months (8.5 years) , then it is almost a certain crash and a no-go.

In other words it is just like the MAX, someone made a decision based on some math done by someone else who thought they understood what was going on presumably by taking someone else's word. The people in the loop work for the government so if they screw up they can't be sued.
 
kalvado
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Re: FAA to prohibit many flight operations due to risk of ‘5G’ wireless interference

Fri Jan 21, 2022 8:49 pm

Revelation wrote:
kalvado wrote:
Chemist wrote:
Somebody please explain to me how hardware approval can be safe enough for a temporary time period, but not safe enough for an indefinite time period.

This reminds me of how Boeing thought the MAX would be safe enough after crash #1 until their software patches would be available.

Risk management. if they estimate <0.01 crash over the month for the fleet, then it is not too bad. If that is allowed to hold for 100 months (8.5 years) , then it is almost a certain crash and a no-go.

In other words it is just like the MAX, someone made a decision based on some math done by someone else who thought they understood what was going on presumably by taking someone else's word. The people in the loop work for the government so if they screw up they can't be sued.

That is the way risk management works, after all. MAX problem was with too optimistic estimate and lack of engineering understanding, not fundamental lack of logic.
So... having said that, I am not really that encouraged any more....
 
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Revelation
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Re: FAA to prohibit many flight operations due to risk of ‘5G’ wireless interference

Fri Jan 21, 2022 9:49 pm

kalvado wrote:
That is the way risk management works, after all. MAX problem was with too optimistic estimate and lack of engineering understanding, not fundamental lack of logic.
So... having said that, I am not really that encouraged any more....

My understanding based on https://www.forbes.com/sites/petercohan ... y-too-low/ and similar reports is FAA assumed after the first crash that the AD they issued would be enough for all pilots worldwide to deal with MCAS and its multiple activations, yet they did no testing at the time to verify that line pilots had even read the AD, never mind understood it, never mind were able to perform all the things it said needed to be performed to correct for an inadvertent MCAS activation triggered by a faulty AoA sensor in the presence of the stick shaker and all the other horns that were triggered by the faulty AoA sensor.

This feels similar to what we're seeing with RADALTs. As far as we can tell, vendors push some paper at FAA that says they think they're cool with regard to operation in the presence of 5G towers, FAA ticks the box, and everyone's on the train home in time for supper.
 
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c933103
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Re: FAA to prohibit many flight operations due to risk of ‘5G’ wireless interference

Sat Jan 22, 2022 7:06 am

frmrCapCadet wrote:
Could passive reflectors in the last ten miles of a flight path be constructed to help with this. Also, could those reflectors be tuned and aimed for maximum reflection back to the plane. Us small boat operators are often told that passive radar reflectors can ensure we are seen.

1. The problem here is not the orthodox signal cannot be received. But rather additional alternative signal from "nearby" bands can also be received by the altimeter and could confuse the equipment. Enhancing the reflection signal can help increase the Signal-Noise Ratio, but if the altimeter is poorly designed and just whatever signal it can receive then it wouldn't help.
2. Building ten miles of reflector track down runway takeoff/approach path is unrealistic. That's like building ten miles of road or rail track with no deviation allowed. The cost of land acquisition is not going to be cheap, if you have observed any road or rail project of similar length. Let alone there can also be bodies of water or sea on the path. Not to mention places with cultural or natural significance. And each runway most likely have multiple takeoff/approach paths, thus multiple such tracks will need to be created. They also have to be wide enough for aircraft in the air..
 
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par13del
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Re: FAA to prohibit many flight operations due to risk of ‘5G’ wireless interference

Sat Jan 22, 2022 2:14 pm

Revelation wrote:
This feels similar to what we're seeing with RADALTs. As far as we can tell, vendors push some paper at FAA that says they think they're cool with regard to operation in the presence of 5G towers, FAA ticks the box, and everyone's on the train home in time for supper.

The fact that such is not taking place with the 777X and 737-10 certifications means what, that there are multiple factions of the FAA in play?
I admit that I like the idea of transmitters around airports as a permanent fix, it is old technology, works every day for ILS, VOR etc., unfortunately this is a long term fix involving hardware, new dual purpose RADALT's, transmitters, stations, turn of the century timing on deployment.
 
kalvado
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Re: FAA to prohibit many flight operations due to risk of ‘5G’ wireless interference

Sat Jan 22, 2022 2:26 pm

par13del wrote:
Revelation wrote:
This feels similar to what we're seeing with RADALTs. As far as we can tell, vendors push some paper at FAA that says they think they're cool with regard to operation in the presence of 5G towers, FAA ticks the box, and everyone's on the train home in time for supper.

The fact that such is not taking place with the 777X and 737-10 certifications means what, that there are multiple factions of the FAA in play?
I admit that I like the idea of transmitters around airports as a permanent fix, it is old technology, works every day for ILS, VOR etc., unfortunately this is a long term fix involving hardware, new dual purpose RADALT's, transmitters, stations, turn of the century timing on deployment.

According to some comments, FAA is getting pain in the butt with new certifications, but it is unclear how much real merit (or ability to provide real thing) is there. So it may be about being tough to previous troublemaker to be clear if (when) things don't go well, and just trying to reduce current trouble at the same time.
 
miegapele
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Re: FAA to prohibit many flight operations due to risk of ‘5G’ wireless interference

Sat Jan 22, 2022 2:42 pm

par13del wrote:
I admit that I like the idea of transmitters around airports as a permanent fix, it is old technology, works every day for ILS, VOR etc., unfortunately thisî is a long term fix involving hardware, new dual purpose RADALT's, transmitters, stations, turn of the century timing on deployment.

But transmitters at the airport require receivers at the plane, the same as current altimeters. So they would need to do the same or probably even more strict filtering to receive that new signal. Seems a lot of work for nothing. Just filter what altimeter receives, it is independent of anything, except for jamming, but all radio waves are suseptible to that.
 
kalvado
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Re: FAA to prohibit many flight operations due to risk of ‘5G’ wireless interference

Sat Jan 22, 2022 3:10 pm

miegapele wrote:
par13del wrote:
I admit that I like the idea of transmitters around airports as a permanent fix, it is old technology, works every day for ILS, VOR etc., unfortunately thisî is a long term fix involving hardware, new dual purpose RADALT's, transmitters, stations, turn of the century timing on deployment.

But transmitters at the airport require receivers at the plane, the same as current altimeters. So they would need to do the same or probably even more strict filtering to receive that new signal. Seems a lot of work for nothing. Just filter what altimeter receives, it is independent of anything, except for jamming, but all radio waves are suseptible to that.

One of ideas which I may want to see implemented somewhere sometime is a local "gps".
Satellite based gps is good for global ops, e.g. for military - who happen to be in control.
Same principle can be used for a local system, with fixed transmitters. Indoor shopping centers or sports venues, dense cities, subways... Runway approaches maybe?
That would require few transmitters in selected spots - such as at cell towers. Nothing really major in terms of construction.
Conceptually similar to differential gps, but can use much higher powers (anything would, after all) and hence be more robust.
 
JibberJim
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Re: FAA to prohibit many flight operations due to risk of ‘5G’ wireless interference

Sat Jan 22, 2022 3:23 pm

kalvado wrote:
One of ideas which I may want to see implemented somewhere sometime is a local "gps".
Satellite based gps is good for global ops, e.g. for military - who happen to be in control.
Same principle can be used for a local system, with fixed transmitters. Indoor shopping centers or sports venues, dense cities, subways... Runway approaches maybe?
That would require few transmitters in selected spots - such as at cell towers. Nothing really major in terms of construction.
Conceptually similar to differential gps, but can use much higher powers (anything would, after all) and hence be more robust.


Would it? the problem with ground transmitters for this is surely that the higher powers mean more reflected signals of buildings etc. which add up to different path lengths etc. One of advantages of GPS is that the signals all come down from the sky, The LAAS system to do the correction to the GPS signals (inaccuracies from weather etc.) would seem to be enough of an improvement on just GPS I'd've thought, as any other similar system will still suffer the same risks of interference/jamming/spoofing but provide no real increase in accuracy.
 
kalvado
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Re: FAA to prohibit many flight operations due to risk of ‘5G’ wireless interference

Sat Jan 22, 2022 3:28 pm

JibberJim wrote:
kalvado wrote:
One of ideas which I may want to see implemented somewhere sometime is a local "gps".
Satellite based gps is good for global ops, e.g. for military - who happen to be in control.
Same principle can be used for a local system, with fixed transmitters. Indoor shopping centers or sports venues, dense cities, subways... Runway approaches maybe?
That would require few transmitters in selected spots - such as at cell towers. Nothing really major in terms of construction.
Conceptually similar to differential gps, but can use much higher powers (anything would, after all) and hence be more robust.


Would it? the problem with ground transmitters for this is surely that the higher powers mean more reflected signals of buildings etc. which add up to different path lengths etc. One of advantages of GPS is that the signals all come down from the sky, The LAAS system to do the correction to the GPS signals (inaccuracies from weather etc.) would seem to be enough of an improvement on just GPS I'd've thought, as any other similar system will still suffer the same risks of interference/jamming/spoofing but provide no real increase in accuracy.

For runway approaches signals can be directed into the sky with no reflections.
Although things will not work great over the runway, at 10 feet altitude.

But this is just a random thought.
 
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par13del
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Re: FAA to prohibit many flight operations due to risk of ‘5G’ wireless interference

Sat Jan 22, 2022 4:42 pm

JibberJim wrote:
kalvado wrote:
One of ideas which I may want to see implemented somewhere sometime is a local "gps".
Satellite based gps is good for global ops, e.g. for military - who happen to be in control.
Same principle can be used for a local system, with fixed transmitters. Indoor shopping centers or sports venues, dense cities, subways... Runway approaches maybe?
That would require few transmitters in selected spots - such as at cell towers. Nothing really major in terms of construction.
Conceptually similar to differential gps, but can use much higher powers (anything would, after all) and hence be more robust.


Would it? the problem with ground transmitters for this is surely that the higher powers mean more reflected signals of buildings etc. which add up to different path lengths etc. One of advantages of GPS is that the signals all come down from the sky, The LAAS system to do the correction to the GPS signals (inaccuracies from weather etc.) would seem to be enough of an improvement on just GPS I'd've thought, as any other similar system will still suffer the same risks of interference/jamming/spoofing but provide no real increase in accuracy.

We are talking around airports, in my line of thinking, so much automation has been configured to use the altimeter functionality, the FAA and airports already have restriction around buildings in the vicinity of airports and their approaches.
Not saying it is the best but as it will be a long term option, my thinking is why not also look at it, sometimes there is no single switch to flick.
 
mxaxai
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Re: FAA to prohibit many flight operations due to risk of ‘5G’ wireless interference

Sat Jan 22, 2022 6:31 pm

Radio altimeters are simple yet precise devices that work without external infrastructure or databases. They're relatively immune to environmental influences and don't need recalibration in-flight. Literally the only drawback is that they're sensitive to RF interference, which wasn't an issue until now.
It makes perfect sense to use the altimeter as a reliable input to various aircraft functions. There's no need to build expensive ground-based infrastructure.
 
kalvado
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Re: FAA to prohibit many flight operations due to risk of ‘5G’ wireless interference

Sat Jan 22, 2022 9:09 pm

mxaxai wrote:
Radio altimeters are simple yet precise devices that work without external infrastructure or databases. They're relatively immune to environmental influences and don't need recalibration in-flight. Literally the only drawback is that they're sensitive to RF interference, which wasn't an issue until now.
It makes perfect sense to use the altimeter as a reliable input to various aircraft functions. There's no need to build expensive ground-based infrastructure.

True, but there are limitations as well. Most obvious is measurement wrt local terrain, which is not always flat.
Without being an expert, I can think of one major crash due to that, and at least one airport where this can be an issue.
 
GalaxyFlyer
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Re: FAA to prohibit many flight operations due to risk of ‘5G’ wireless interference

Sat Jan 22, 2022 9:26 pm

kalvado wrote:
mxaxai wrote:
Radio altimeters are simple yet precise devices that work without external infrastructure or databases. They're relatively immune to environmental influences and don't need recalibration in-flight. Literally the only drawback is that they're sensitive to RF interference, which wasn't an issue until now.
It makes perfect sense to use the altimeter as a reliable input to various aircraft functions. There's no need to build expensive ground-based infrastructure.

True, but there are limitations as well. Most obvious is measurement wrt local terrain, which is not always flat.
Without being an expert, I can think of one major crash due to that, and at least one airport where this can be an issue.


Where the RADALT is critical is on low visibility approaches and the terrain is surveyed or remediated, as necessary, so the radar altimeters work fine for their intended purpose. Do you have a link to an accident report where erroneous RADALT was causal to an accident, please?
 
kalvado
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Re: FAA to prohibit many flight operations due to risk of ‘5G’ wireless interference

Sat Jan 22, 2022 9:31 pm

GalaxyFlyer wrote:
kalvado wrote:
mxaxai wrote:
Radio altimeters are simple yet precise devices that work without external infrastructure or databases. They're relatively immune to environmental influences and don't need recalibration in-flight. Literally the only drawback is that they're sensitive to RF interference, which wasn't an issue until now.
It makes perfect sense to use the altimeter as a reliable input to various aircraft functions. There's no need to build expensive ground-based infrastructure.

True, but there are limitations as well. Most obvious is measurement wrt local terrain, which is not always flat.
Without being an expert, I can think of one major crash due to that, and at least one airport where this can be an issue.


Where the RADALT is critical is on low visibility approaches and the terrain is surveyed or remediated, as necessary, so the radar altimeters work fine for their intended purpose. Do you have a link to an accident report where erroneous RADALT was causal to an accident, please?

Not a link, but should be easy to find - Polish presidential aircraft crash. Pilot was trying to land in dense fog, descended by radalt - and ended up flying below runway level and into rising terrain.
 
mxaxai
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Re: FAA to prohibit many flight operations due to risk of ‘5G’ wireless interference

Sat Jan 22, 2022 10:07 pm

kalvado wrote:
Not a link, but should be easy to find - Polish presidential aircraft crash. Pilot was trying to land in dense fog, descended by radalt - and ended up flying below runway level and into rising terrain.

The crew of that flight attempted to descend below the published minimums and ignored the warnings of its TAWS (an EGPWS variant using barometric altitude and GPS position, which allowed the crew to mute the warning by changing the reference pressure; most other EGPWS use the radio altimeter fused with GPS because it's more reliable). You can't fault the instrument when it's used for something it wasn't intended for.
 
kalvado
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Re: FAA to prohibit many flight operations due to risk of ‘5G’ wireless interference

Sat Jan 22, 2022 10:14 pm

mxaxai wrote:
kalvado wrote:
Not a link, but should be easy to find - Polish presidential aircraft crash. Pilot was trying to land in dense fog, descended by radalt - and ended up flying below runway level and into rising terrain.

The crew of that flight attempted to descend below the published minimums and ignored the warnings of its TAWS (an EGPWS variant using barometric altitude and GPS position, which allowed the crew to mute the warning by changing the reference pressure; most other EGPWS use the radio altimeter fused with GPS because it's more reliable). You can't fault the instrument when it's used for something it wasn't intended for.

True, altimeter was only a small part with very determined pilots being main issue. But situation highlights the limitations of the instrument.
Last edited by kalvado on Sat Jan 22, 2022 10:17 pm, edited 1 time in total.
 
Airplanebrain
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Re: FAA to prohibit many flight operations due to risk of ‘5G’ wireless interference

Sat Jan 22, 2022 10:15 pm

Airline CEOs make U-turn, now say 5G isn’t a big problem for altimeters

https://arstechnica.com/tech-policy/202 ... ltimeters/
 
GalaxyFlyer
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Re: FAA to prohibit many flight operations due to risk of ‘5G’ wireless interference

Sat Jan 22, 2022 10:26 pm

RADALT played zero in the accident. Crew was pressured and failed to resist thd pressure and flew below the established minimums. I’m trying what limitation in the RADALT was causal?
 
GalaxyFlyer
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Re: FAA to prohibit many flight operations due to risk of ‘5G’ wireless interference

Sat Jan 22, 2022 10:29 pm

mxaxai wrote:
kalvado wrote:
Not a link, but should be easy to find - Polish presidential aircraft crash. Pilot was trying to land in dense fog, descended by radalt - and ended up flying below runway level and into rising terrain.

The crew of that flight attempted to descend below the published minimums and ignored the warnings of its TAWS (an EGPWS variant using barometric altitude and GPS position, which allowed the crew to mute the warning by changing the reference pressure; most other EGPWS use the radio altimeter fused with GPS because it's more reliable). You can't fault the instrument when it's used for something it wasn't intended for.


They didn’t attempt to descend minimums—They did so. TAWS isn’t a variation of EGPWS, but a generic term for Honeywell’s trademarked EGPWS. Both use radar altimeter heights, along with terrain database, GPS position data to provide warnings.
 
kalvado
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Re: FAA to prohibit many flight operations due to risk of ‘5G’ wireless interference

Sat Jan 22, 2022 10:35 pm

GalaxyFlyer wrote:
RADALT played zero in the accident. Crew was pressured and failed to resist thd pressure and flew below the established minimums. I’m trying what limitation in the RADALT was causal?

Radalt is obviously not the root cause, no questions.
But just imagine they had a precise way of flying 200 feet over runway level on flat terrain. There would be no crash.
Immediate reason for the crash was flying radalt altitude looking for runway instead of fixed over sea level (or how to say that?), which happened to be too low.
 
GalaxyFlyer
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Re: FAA to prohibit many flight operations due to risk of ‘5G’ wireless interference

Sat Jan 22, 2022 11:09 pm

That’s called Terrain Following Radar and that’s the province of military attack aircraft. The F-111 had it 55 years ago. The immediate cause was pilots, under pressure by a commander who had not business being involved, to try to use radar altitude and TAWS in a manner specifically NOT authorized for use. Every TAWS very clearly states in training—not to be used for navigation. Had they not flown the plane below the minimums (either QFE or QNH defined, Russia still used QFE heights) they wouldn’t have the ground or landed.

I had the privilege to meet the senior officers sent by Poland to begin the diplomatic effort on recovery, funny enough, we were all checking in at a Moscow hotel at the same time. Just pleasantries, but very somber team.
 
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par13del
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Re: FAA to prohibit many flight operations due to risk of ‘5G’ wireless interference

Sat Jan 22, 2022 11:49 pm

mxaxai wrote:
Radio altimeters are simple yet precise devices that work without external infrastructure or databases. They're relatively immune to environmental influences and don't need recalibration in-flight. Literally the only drawback is that they're sensitive to RF interference, which wasn't an issue until now.
It makes perfect sense to use the altimeter as a reliable input to various aircraft functions. There's no need to build expensive ground-based infrastructure.

Times change, we now have internet without cables and interference has arrived. Now we can go as some say that aviation was here first and sit and wait for the telecoms to go elsewhere, but since they already spent billions, I think sitting and doing nothing is not a desired option. As stated, we are looking at options, not saying that this is what they should do.
 
DLPMMM
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Re: FAA to prohibit many flight operations due to risk of ‘5G’ wireless interference

Sun Jan 23, 2022 1:14 am

par13del wrote:
mxaxai wrote:
Radio altimeters are simple yet precise devices that work without external infrastructure or databases. They're relatively immune to environmental influences and don't need recalibration in-flight. Literally the only drawback is that they're sensitive to RF interference, which wasn't an issue until now.
It makes perfect sense to use the altimeter as a reliable input to various aircraft functions. There's no need to build expensive ground-based infrastructure.

Times change, we now have internet without cables and interference has arrived. Now we can go as some say that aviation was here first and sit and wait for the telecoms to go elsewhere, but since they already spent billions, I think sitting and doing nothing is not a desired option. As stated, we are looking at options, not saying that this is what they should do.



The solution is simple. C band band pass filters for radar applications are already on the market as a standard product.

Here is an example from a quick Google search:

http://microwavefilter.com.s3-website-u ... d-lp3.html

Fix the stupid 1970’s technology receivers to not pick up extraneous RF signals outside the receivers designated wavelengths.
 
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Revelation
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Re: FAA to prohibit many flight operations due to risk of ‘5G’ wireless interference

Sun Jan 23, 2022 2:02 am

DLPMMM wrote:
Fix the stupid 1970’s technology receivers to not pick up extraneous RF signals outside the receivers designated wavelengths.

Or, if you're the airline industry just do nothing till the spam hits the fan then tell everyone about the chaos and they wont be flying then wait for FAA to get some numbers from some vendors and then use the rubber stamp to make it all go away.
 
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par13del
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Re: FAA to prohibit many flight operations due to risk of ‘5G’ wireless interference

Sun Jan 23, 2022 6:08 am

Revelation wrote:
DLPMMM wrote:
Fix the stupid 1970’s technology receivers to not pick up extraneous RF signals outside the receivers designated wavelengths.

Or, if you're the airline industry just do nothing till the spam hits the fan then tell everyone about the chaos and they wont be flying then wait for FAA to get some numbers from some vendors and then use the rubber stamp to make it all go away.

Works for domestic carriers, but I do not believe that foreign airlines will be comfortable with such assurances from the FAA, liability only goes so far internationally.
So if they are unable to use certain a/c in their fleet or do not have options they may be difficult, not sure there is much they can do other than to make noise and once again put the FAA under a new microscope.
 
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c933103
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Re: FAA to prohibit many flight operations due to risk of ‘5G’ wireless interference

Sun Jan 23, 2022 6:39 am

par13del wrote:
Revelation wrote:
DLPMMM wrote:
Fix the stupid 1970’s technology receivers to not pick up extraneous RF signals outside the receivers designated wavelengths.

Or, if you're the airline industry just do nothing till the spam hits the fan then tell everyone about the chaos and they wont be flying then wait for FAA to get some numbers from some vendors and then use the rubber stamp to make it all go away.

Works for domestic carriers, but I do not believe that foreign airlines will be comfortable with such assurances from the FAA, liability only goes so far internationally.
So if they are unable to use certain a/c in their fleet or do not have options they may be difficult, not sure there is much they can do other than to make noise and once again put the FAA under a new microscope.

Those foreign airlines are not flying some specific model of aircraft simply due to the directive. They're flying those aircraft in their own country with 5G in relevant frequency band switched on without much apparent problems.
 
Snowfalcon
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Re: FAA to prohibit many flight operations due to risk of ‘5G’ wireless interference

Sun Jan 23, 2022 9:39 am

DLPMMM wrote:


The solution is simple. C band band pass filters for radar applications are already on the market as a standard product.

Here is an example from a quick Google search:
http://microwavefilter.com.s3-website-u ... d-lp3.html

Fix the stupid 1970’s technology receivers to not pick up extraneous RF signals outside the receivers designated wavelengths.


Nit-picking: Unfortunately it seems the filters on the linked page don't work for radio altimeters.

First, the passband needs to be 4.2-4.4 GHz, to let the radio altimeter signal through but suppress 5G signals below 3.98 GHz.
The filters shown are presumably intended for satellite communication receivers operating in the 4.0 to 4.2 GHz band between 5G and the radio altimeters. (The sat industry is also affected by 5G).

Second, these are waveguide filters, while on the radio altimeters (and their antennas) that I've seen the RF connection is by coaxial cable.
Third, the product needs to be certified for aircraft use.

In principle your point is correct, designing and manufacturing an add-on bandpass filter for the radio altimeter band is possible. However, it's not trivial either. There are physical limits for how "steep" you can make the response of a simple filter before you start distorting the signal, which may then affect the altimeter receiver performance. But I am sure several companies are already working on this. Hopefully a solution is found.
 
mxaxai
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Re: FAA to prohibit many flight operations due to risk of ‘5G’ wireless interference

Sun Jan 23, 2022 11:33 am

DLPMMM wrote:
The solution is simple. C band band pass filters for radar applications are already on the market as a standard product.

Exactly. Well, I'm not sure if the exact filters that are needed are already available, but it's a relatively minor challenge compared to the ground-based solutions some are advertising here. There are also other options to improve signal-to-noise ratio and robustness to interference.
If the altimeter manufacturers have to design it from scratch, you might be looking at a year or two for the design and certification, still much faster to market than anything ground based.
 
kalvado
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Re: FAA to prohibit many flight operations due to risk of ‘5G’ wireless interference

Sun Jan 23, 2022 12:03 pm

Snowfalcon wrote:
DLPMMM wrote:


The solution is simple. C band band pass filters for radar applications are already on the market as a standard product.

Here is an example from a quick Google search:
http://microwavefilter.com.s3-website-u ... d-lp3.html

Fix the stupid 1970’s technology receivers to not pick up extraneous RF signals outside the receivers designated wavelengths.


Nit-picking: Unfortunately it seems the filters on the linked page don't work for radio altimeters.

First, the passband needs to be 4.2-4.4 GHz, to let the radio altimeter signal through but suppress 5G signals below 3.98 GHz.
The filters shown are presumably intended for satellite communication receivers operating in the 4.0 to 4.2 GHz band between 5G and the radio altimeters. (The sat industry is also affected by 5G).

Second, these are waveguide filters, while on the radio altimeters (and their antennas) that I've seen the RF connection is by coaxial cable.
Third, the product needs to be certified for aircraft use.

In principle your point is correct, designing and manufacturing an add-on bandpass filter for the radio altimeter band is possible. However, it's not trivial either. There are physical limits for how "steep" you can make the response of a simple filter before you start distorting the signal, which may then affect the altimeter receiver performance. But I am sure several companies are already working on this. Hopefully a solution is found.

As for readily available filters, their assortment is driven by demand more than anything else. If there is significant demand for wifi, Bluetooth or gps band filters, they would be readily available. There is no demand for a semi-random reserved band, hence nothing off the shelf.
Getting a custom one designed and built is very possible, especially with 4-digit order.
 
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par13del
Posts: 11467
Joined: Sun Dec 18, 2005 9:14 pm

Re: FAA to prohibit many flight operations due to risk of ‘5G’ wireless interference

Sun Jan 23, 2022 3:13 pm

c933103 wrote:
par13del wrote:
Revelation wrote:
Or, if you're the airline industry just do nothing till the spam hits the fan then tell everyone about the chaos and they wont be flying then wait for FAA to get some numbers from some vendors and then use the rubber stamp to make it all go away.

Works for domestic carriers, but I do not believe that foreign airlines will be comfortable with such assurances from the FAA, liability only goes so far internationally.
So if they are unable to use certain a/c in their fleet or do not have options they may be difficult, not sure there is much they can do other than to make noise and once again put the FAA under a new microscope.

Those foreign airlines are not flying some specific model of aircraft simply due to the directive. They're flying those aircraft in their own country with 5G in relevant frequency band switched on without much apparent problems.

We already know that the implementation of 5G in the USA and elsewhere in the world is not the same, hence foreign carriers swapping out equipment, at least those who can.
 
kalvado
Posts: 3748
Joined: Wed Mar 01, 2006 4:29 am

Re: FAA to prohibit many flight operations due to risk of ‘5G’ wireless interference

Sun Jan 23, 2022 4:04 pm

par13del wrote:
c933103 wrote:
par13del wrote:
Works for domestic carriers, but I do not believe that foreign airlines will be comfortable with such assurances from the FAA, liability only goes so far internationally.
So if they are unable to use certain a/c in their fleet or do not have options they may be difficult, not sure there is much they can do other than to make noise and once again put the FAA under a new microscope.

Those foreign airlines are not flying some specific model of aircraft simply due to the directive. They're flying those aircraft in their own country with 5G in relevant frequency band switched on without much apparent problems.

We already know that the implementation of 5G in the USA and elsewhere in the world is not the same, hence foreign carriers swapping out equipment, at least those who can.

It's not really about technical implementation. This is a case study for big business not caring about anyone - including paying customers, and big government dysfunction.
A good investigation is certainly warranted, even if no criminal charges are to happen - but agencies which should be doing that are too busy with political witch hunt. So things are not going to improve.
 
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Revelation
Posts: 27477
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Re: FAA to prohibit many flight operations due to risk of ‘5G’ wireless interference

Sun Jan 23, 2022 4:24 pm

Snowfalcon wrote:
In principle your point is correct, designing and manufacturing an add-on bandpass filter for the radio altimeter band is possible. However, it's not trivial either. There are physical limits for how "steep" you can make the response of a simple filter before you start distorting the signal, which may then affect the altimeter receiver performance. But I am sure several companies are already working on this. Hopefully a solution is found.

I agree. The solution is simple in concept, but not so simple in practice.

I have yet to read anything about how the AMOC process is being conducted. I hope we're not looking at MCAS V2.

kalvado wrote:
A good investigation is certainly warranted, even if no criminal charges are to happen - but agencies which should be doing that are too busy with political witch hunt. So things are not going to improve.

I think it should be pointed out that it's been a political agenda to downsize the regulatory authorities in general and then to often staff the executive positions with people with a non-technical background and an anti-regulatory stance. You get the government you elect.
 
32andBelow
Posts: 6315
Joined: Mon Sep 03, 2012 2:54 am

Re: FAA to prohibit many flight operations due to risk of ‘5G’ wireless interference

Sun Jan 23, 2022 7:57 pm

Revelation wrote:
Snowfalcon wrote:
In principle your point is correct, designing and manufacturing an add-on bandpass filter for the radio altimeter band is possible. However, it's not trivial either. There are physical limits for how "steep" you can make the response of a simple filter before you start distorting the signal, which may then affect the altimeter receiver performance. But I am sure several companies are already working on this. Hopefully a solution is found.

I agree. The solution is simple in concept, but not so simple in practice.

I have yet to read anything about how the AMOC process is being conducted. I hope we're not looking at MCAS V2.

kalvado wrote:
A good investigation is certainly warranted, even if no criminal charges are to happen - but agencies which should be doing that are too busy with political witch hunt. So things are not going to improve.

I think it should be pointed out that it's been a political agenda to downsize the regulatory authorities in general and then to often staff the executive positions with people with a non-technical background and an anti-regulatory stance. You get the government you elect.

They’ve also been working from home. AKA not working since the beginning of the pandemic
 
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c933103
Posts: 6692
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Re: FAA to prohibit many flight operations due to risk of ‘5G’ wireless interference

Sun Jan 23, 2022 8:35 pm

par13del wrote:
c933103 wrote:
par13del wrote:
Works for domestic carriers, but I do not believe that foreign airlines will be comfortable with such assurances from the FAA, liability only goes so far internationally.
So if they are unable to use certain a/c in their fleet or do not have options they may be difficult, not sure there is much they can do other than to make noise and once again put the FAA under a new microscope.

Those foreign airlines are not flying some specific model of aircraft simply due to the directive. They're flying those aircraft in their own country with 5G in relevant frequency band switched on without much apparent problems.

We already know that the implementation of 5G in the USA and elsewhere in the world is not the same, hence foreign carriers swapping out equipment, at least those who can.

As already posted upthread, frequency used by Japanese 5G signal are even closer to the altimeter band in question than those in the US yet none of the airlines have problem with their domestic operation or carrier from nearby countries or US carriers flying into Japan
 
mxaxai
Posts: 3295
Joined: Sat Jun 18, 2016 7:29 am

Re: FAA to prohibit many flight operations due to risk of ‘5G’ wireless interference

Sun Jan 23, 2022 8:56 pm

Revelation wrote:
I think it should be pointed out that it's been a political agenda to downsize the regulatory authorities in general and then to often staff the executive positions with people with a non-technical background and an anti-regulatory stance. You get the government you elect.

Small government and lean management are pretty popular positions in the US.

I guess what we're seeing here is a cultural clash between a heavily regulated, safety-focused and stagnant industry and a relatively unregulated service-focused and rapidly growing industry, and their respective political representations in the shape of FAA and FCC. 7 of the top 10 companies by market cap are active in the telecommunications industry, none are aircraft manufacturers - aviation's no. 1, Boeing, isn't even under the top 100 companies.
 
kalvado
Posts: 3748
Joined: Wed Mar 01, 2006 4:29 am

Re: FAA to prohibit many flight operations due to risk of ‘5G’ wireless interference

Sun Jan 23, 2022 9:36 pm

mxaxai wrote:
Revelation wrote:
I think it should be pointed out that it's been a political agenda to downsize the regulatory authorities in general and then to often staff the executive positions with people with a non-technical background and an anti-regulatory stance. You get the government you elect.

Small government and lean management are pretty popular positions in the US.

I guess what we're seeing here is a cultural clash between a heavily regulated, safety-focused and stagnant industry and a relatively unregulated service-focused and rapidly growing industry, and their respective political representations in the shape of FAA and FCC. 7 of the top 10 companies by market cap are active in the telecommunications industry, none are aircraft manufacturers - aviation's no. 1, Boeing, isn't even under the top 100 companies.

Frankly speaking, "safety orientated" is a wishful thinking item at best by now. Compliance oriented is a better way of putting it.
 
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par13del
Posts: 11467
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Re: FAA to prohibit many flight operations due to risk of ‘5G’ wireless interference

Sun Jan 23, 2022 9:46 pm

c933103 wrote:
par13del wrote:
c933103 wrote:
Those foreign airlines are not flying some specific model of aircraft simply due to the directive. They're flying those aircraft in their own country with 5G in relevant frequency band switched on without much apparent problems.

We already know that the implementation of 5G in the USA and elsewhere in the world is not the same, hence foreign carriers swapping out equipment, at least those who can.

As already posted upthread, frequency used by Japanese 5G signal are even closer to the altimeter band in question than those in the US yet none of the airlines have problem with their domestic operation or carrier from nearby countries or US carriers flying into Japan

This thread is about the 5G implementation in the USA, that 5G works fine for JAL in Japan has nothing to do with them swapping out equipment to operate their flights into the USA.
The FAA stop gap measures have nothing to do with 5G in other countries.
 
N649DL
Posts: 1299
Joined: Sat Aug 25, 2018 10:21 pm

Re: FAA to prohibit many flight operations due to risk of ‘5G’ wireless interference

Sun Jan 23, 2022 10:14 pm

I wonder (off topic but reading up on it last night) but how does 5G also affect the EAS system frequencies and deployment, if anything? https://en.wikipedia.org/wiki/Specific_ ... e_Encoding

Also rolled out in 2021 were the first examples of an Earthquake Warning System on the West Coast: https://en.wikipedia.org/wiki/Earthquake_warning_system
 
kalvado
Posts: 3748
Joined: Wed Mar 01, 2006 4:29 am

Re: FAA to prohibit many flight operations due to risk of ‘5G’ wireless interference

Sun Jan 23, 2022 10:17 pm

N649DL wrote:
I wonder (off topic but reading up on it last night) but how does 5G also affect the EAS system frequencies and deployment, if anything? https://en.wikipedia.org/wiki/Specific_ ... e_Encoding

Also rolled out in 2021 were the first examples of an Earthquake Warning System on the West Coast: https://en.wikipedia.org/wiki/Earthquake_warning_system


totally different frequency range, so 99.99% there is no effect at all.
 
hivue
Posts: 2204
Joined: Tue Feb 26, 2013 2:26 am

Re: FAA to prohibit many flight operations due to risk of ‘5G’ wireless interference

Sun Jan 23, 2022 10:44 pm

c933103 wrote:
As already posted upthread, frequency used by Japanese 5G signal are even closer to the altimeter band in question than those in the US yet none of the airlines have problem with their domestic operation or carrier from nearby countries or US carriers flying into Japan


I replied to one of those posts upthread that here apparently is the solution to the problem. Just have Verizon and AT&T (re-) deploy their C-band 5G the same way as Japan has (or France or any other of these enlightened nations where 5G and radio altimeters are happily coexisting).
 
kalvado
Posts: 3748
Joined: Wed Mar 01, 2006 4:29 am

Re: FAA to prohibit many flight operations due to risk of ‘5G’ wireless interference

Sun Jan 23, 2022 10:47 pm

hivue wrote:
c933103 wrote:
As already posted upthread, frequency used by Japanese 5G signal are even closer to the altimeter band in question than those in the US yet none of the airlines have problem with their domestic operation or carrier from nearby countries or US carriers flying into Japan


I replied to one of those posts upthread that here apparently is the solution to the problem. Just have Verizon and AT&T (re-) deploy their C-band 5G the same way as Japan has (or France or any other of these enlightened nations where has 5G and radio altimeters are happily coexisting).

If - I know it is an impossible assumption, but just imagine for a second - FAA and avionics vendors joining the discussion and trying to sort things out a bit in advance...
 
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c933103
Posts: 6692
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Re: FAA to prohibit many flight operations due to risk of ‘5G’ wireless interference

Mon Jan 24, 2022 3:23 am

par13del wrote:
c933103 wrote:
par13del wrote:
We already know that the implementation of 5G in the USA and elsewhere in the world is not the same, hence foreign carriers swapping out equipment, at least those who can.

As already posted upthread, frequency used by Japanese 5G signal are even closer to the altimeter band in question than those in the US yet none of the airlines have problem with their domestic operation or carrier from nearby countries or US carriers flying into Japan

This thread is about the 5G implementation in the USA, that 5G works fine for JAL in Japan has nothing to do with them swapping out equipment to operate their flights into the USA.
The FAA stop gap measures have nothing to do with 5G in other countries.

hivue wrote:
c933103 wrote:
As already posted upthread, frequency used by Japanese 5G signal are even closer to the altimeter band in question than those in the US yet none of the airlines have problem with their domestic operation or carrier from nearby countries or US carriers flying into Japan


I replied to one of those posts upthread that here apparently is the solution to the problem. Just have Verizon and AT&T (re-) deploy their C-band 5G the same way as Japan has (or France or any other of these enlightened nations where 5G and radio altimeters are happily coexisting).


radio waves are radio waves. Their physical characteristic aren't going to change just because they're in different countries.
 
USAirKid
Posts: 1370
Joined: Mon Jun 13, 2016 5:42 am

Re: FAA to prohibit many flight operations due to risk of ‘5G’ wireless interference

Mon Jan 24, 2022 3:54 am

kalvado wrote:
It's not really about technical implementation. This is a case study for big business not caring about anyone - including paying customers, and big government dysfunction.
A good investigation is certainly warranted, even if no criminal charges are to happen - but agencies which should be doing that are too busy with political witch hunt. So things are not going to improve.


It’s pretty unlikely that anything criminal happened. If it did it would be the jurisdiction of the Department of Justice/FBI.

I’m the executive branch, this sort of investigation would be carried out by the Office of the Inspector General over the FCC and FAA.

On the congressional side this would be a committee investigation. In the House that would be the Committee on Transportation and Infrastructure for the FAA and the Committee on Energy and Commerce. In the Senate that would be the Committee on Commerce, Science, and Transportation.

None of the Inspector Generals nor the relevant congressional committee are currently involved in a “political witch hunt”.
 
mxaxai
Posts: 3295
Joined: Sat Jun 18, 2016 7:29 am

Re: FAA to prohibit many flight operations due to risk of ‘5G’ wireless interference

Mon Jan 24, 2022 7:39 am

kalvado wrote:
If - I know it is an impossible assumption, but just imagine for a second - FAA and avionics vendors joining the discussion and trying to sort things out a bit in advance...

On the other hand, this problem would not exist without the FAA doing things. So I guess less involvement on the regulators' side would be another solution.
 
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par13del
Posts: 11467
Joined: Sun Dec 18, 2005 9:14 pm

Re: FAA to prohibit many flight operations due to risk of ‘5G’ wireless interference

Mon Jan 24, 2022 12:16 pm

c933103 wrote:
par13del wrote:
c933103 wrote:
As already posted upthread, frequency used by Japanese 5G signal are even closer to the altimeter band in question than those in the US yet none of the airlines have problem with their domestic operation or carrier from nearby countries or US carriers flying into Japan

This thread is about the 5G implementation in the USA, that 5G works fine for JAL in Japan has nothing to do with them swapping out equipment to operate their flights into the USA.
The FAA stop gap measures have nothing to do with 5G in other countries.

hivue wrote:
c933103 wrote:
As already posted upthread, frequency used by Japanese 5G signal are even closer to the altimeter band in question than those in the US yet none of the airlines have problem with their domestic operation or carrier from nearby countries or US carriers flying into Japan


I replied to one of those posts upthread that here apparently is the solution to the problem. Just have Verizon and AT&T (re-) deploy their C-band 5G the same way as Japan has (or France or any other of these enlightened nations where 5G and radio altimeters are happily coexisting).


radio waves are radio waves. Their physical characteristic aren't going to change just because they're in different countries.

I thought this was about the USA implementation using much more power, where they position the towers around airports and whether the antennae's were pointed up, level or down, filters if any on all equipment were adequate to prevent interference. However, you are absolutely correct, the physical character of the radio waves do not change anywhere inthe world.
Hopefully the FAA will get this all resolved sometime soon and everyone can go back to operating equipment as they would like and the additional delay will be gone.
 
adipasqu
Posts: 265
Joined: Wed Apr 21, 2004 1:37 pm

Re: FAA to prohibit many flight operations due to risk of ‘5G’ wireless interference

Tue Jan 25, 2022 8:26 pm

The latest from https://www.faa.gov/5g:

Estimated % of U.S. Commercial Fleet Aircraft Models with Installations: 90%

Models with one of 20 cleared altimeters include:

All Boeing 717, 737, 747, 757, 767, 777, 787
MD-10/-11
Airbus A300, A310, A319, A220, A320, A321, A330, A340, A350, A380
Embraer 120, 170, and 190 regional jets
All CL-600/CRJ regional jets
DHC-8 turboprops
ATR turboprops
 
Western727
Posts: 2386
Joined: Wed Jan 03, 2007 12:38 pm

Re: FAA to prohibit many flight operations due to risk of ‘5G’ wireless interference

Tue Jan 25, 2022 8:36 pm

adipasqu wrote:
The latest from https://www.faa.gov/5g:

Estimated % of U.S. Commercial Fleet Aircraft Models with Installations: 90%

Models with one of 20 cleared altimeters include:

All Boeing 717, 737, 747, 757, 767, 777, 787
MD-10/-11
Airbus A300, A310, A319, A220, A320, A321, A330, A340, A350, A380
Embraer 120, 170, and 190 regional jets
All CL-600/CRJ regional jets
DHC-8 turboprops
ATR turboprops


Super...I'm trying to figure out what's left in the US commercial fleet from that list...the only thing that comes to mind is the ERJ-135/140/145, and I feel like these rep less than 10% of the fleet, so what am I missing, if anything?
 
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Thunderboltdrgn
Posts: 2429
Joined: Wed Jan 18, 2012 5:39 pm

Re: FAA to prohibit many flight operations due to risk of ‘5G’ wireless interference

Tue Jan 25, 2022 8:44 pm

Western727 wrote:
adipasqu wrote:
The latest from https://www.faa.gov/5g:

Estimated % of U.S. Commercial Fleet Aircraft Models with Installations: 90%

Models with one of 20 cleared altimeters include:

All Boeing 717, 737, 747, 757, 767, 777, 787
MD-10/-11
Airbus A300, A310, A319, A220, A320, A321, A330, A340, A350, A380
Embraer 120, 170, and 190 regional jets
All CL-600/CRJ regional jets
DHC-8 turboprops
ATR turboprops


Super...I'm trying to figure out what's left in the US commercial fleet from that list...the only thing that comes to mind is the ERJ-135/140/145, and I feel like these rep less than 10% of the fleet, so what am I missing, if anything?


MD=80/90s are still flying in the US but is not listed. and maybe some Avro./Bae?
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