5G rad alts vs the FAA ? 1

[rb1957]

from flight ...
"International carriers warn new 5G altimeter requirements could prevent US flights next year
15 Nov 2022

Non-US airlines are struggling to complete radio altimeter retrofits ahead of looming deadlines established to prevent 5G interference, meaning some carriers’ flights to the USA could be restricted in 2023."

why "non-US" airlines ? why would non-US airlines limit their flights to the US next year because of this issue ?? (yeah, I know ... 'cause their planes aren't compliant)

but "surely" this is a global issue and EASA has the same requirements for 5G ?





"Hoffen wir mal, dass alles gut geht !"
General Paulus, Nov 1942, outside Stalingrad after the launch of Operation Uranus.

 

[3DDave]

5G is an overall communications spec, not a frequency or power spec. In other countries they either have left a larger band gap for their 5G from the rad alt frequency or have required beam forming the prevents the very directional high-power towers from overlapping aircraft approach paths at airports.

In the US the FCC told the FAA to pound sand. To be fair it's been in the works for a long time and the FAA apparently dragged their butts.

 

[Sparweb]

I'm still waiting to read the Service Difficulty Report that goes:
"Radalt temporarily erratic on approach" or something similar in downstream equipment like EGPWS. If the radio altimeter is receiving an interfering signal, then it would not necessarily throw a fault, but instead give nonsense data.

You can check recent SDR's if you want:

https://sdrs.faa.gov/Query.aspx

Selecting "radio altimeter" problems for the last 3 years turns up a few broken boxes and an possible bickering session at one airline between pilots and maintenance crews but no wonky rad alt's. there is one instance of an EGPWS warning of terrain while the plane was at 10,000 feet, but standard troubleshooting revealed the problem in the EGPWS computer.

If any pilots were actually reporting problems, either in Europe or anywhere else in the world that has already deployed 5G near airports, you'd think we would have heard about it by now, and it would have formed part of the story for the journalists? So far it's all a "potential" problem.

 

[rb1957]

so EASA already have this taken care of (so non-US carriers are covered) ?
(ok, not all non-US are European ... geeze)

or in Europe they have ensured there is no conflict between 5G and airports (not sure how that'd be done ... but then I'm not a sparky).

"Hoffen wir mal, dass alles gut geht !"
General Paulus, Nov 1942, outside Stalingrad after the launch of Operation Uranus.

 

[LittleInch]

Discussed in depth here.

https://www.eng-tips.com/viewthread.cfm?qid=490359

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[WKTaylor]

Related... to keep you awake at night... a small taste as to 'reasons why' autonomous vehicle operations are so difficult... and a look into the future of electronic 'fog'.

5G [C-Band] and Aviation Safety

https://www.faa.gov/5g

How 5G’s Rollout Rattled Hundreds of Pilots Complaints about altimeter failures jumped after consumer C-band deployment spectrum.ieee.org

https://spectrum.ieee.org/faa-5g

5G may have caused dozens of troubling in-flight avionics failures

http://www.flightglobal.com

The Federal Aviation Administration (FAA) suspects new 5G cellular networks may have caused roughly 80 instances of aircraft system interference this year, with pilots reporting a range of malfunctions since the latest generation of mobile connectivity went live in January.

https://www.flightglobal.com/safety...g-in-flight-avionics-failures/150780.article?

The effect of Electronic Jammers on GPS Signals ieeexplore.ieee.org
Global Positioning System (GPS) has found wide application in many areas of our daily life. However, it has a very week signal making it vulnerable to external attacks like blocking, jamming or spoofing. Jamming is a technique that blocks the GPS from receiving location signals making it...

https://ieeexplore.ieee.org/document/8893239

Military Tests that Jam and Spoof GPS Signals are an Accident Waiting to Happen ieeexplore.ieee.org
Early one morning last May, a commercial airliner was approaching El Paso International Airport, in West Texas, when a warning popped up in the cockpit: “GPS Position Lost.” The pilot contacted the airline's operations center and received a report that the U.S. Army's White Sands Missile Range...

https://ieeexplore.ieee.org/document/9340116

And reports are that Russia is Jamming and spoofing GPS/GNSS across Ukraine, which is potentially 'bleeding-over' into the EU/NATO.

Regards, Wil Taylor
o Trust - But Verify!
o For those who believe, no proof is required; for those who cannot believe, no proof is possible. [variation, Stuart Chase]
o Unfortunately, in science what You 'believe' is irrelevant. ["Orion", HBA forum]
o Only fools and charlatans know everything and understand everything." -Anton Chekhov

 

[rb1957]

thx, so the issue is the US opened up a high frequency band (that no one ? else did) and this causes issues with the rad alts ?

"Hoffen wir mal, dass alles gut geht !"
General Paulus, Nov 1942, outside Stalingrad after the launch of Operation Uranus.

 

[LittleInch]

That looks like it.

The band the FCC authorise for 5G telecoms seems to be up to 3.98 GHtz

Radio altimeters appear to operate starting at 4.2 - 4.4 GHtz. The filters on some of these Rad alts seem to be quite wide so a lot of other places seem to restrict 5G to no more than 3.7 GHtz

At least that's my very summary understanding.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[debodine]

Going way back down memory lane, but if I recall correctly the low-range radio altimeter in its current form regarding bandwidth usage has been around since at least the Collins 860F-1 R/T I used to work on for the KC-135A in 1974. As I am sure you understand, the bandwidth protections back then were primarily controlled by keeping the bands far apart, and really tight filtering was not necessary. Such a design philosophy no longer works in today's frequency spectrum usage.

I can't speak for the FAA, but it seems they might have considered requiring better filtering and other bandwidth protections at least a decade or so ago when I think this subject was first introduced. Ideally the protections could have (and should have) been in place thru OEM modifications/upgrades etc., of the radio altimeter systems before the 5G spectrum was implemented.

 

[LittleInch]

I think most people agree with you, but the certification required for aircraft systems is unreal so once someone has an item which works and has all the right bits of paper, then they don't want to spend any money on creating a new one unless absolutely forced to.

The battle between the FCC and the FAA and also not getting in tune with the rest of the world (why should we - we're AMERICAN) is coming home to roost.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[Sparweb]

Wil,
That's a better starting point that what I tried to provide, but... It's all still "unable to rule out" and "suspected" and "possibly caused by" kinds of reports.

My engineering staff do EMI and function checks all the time, and pretty often they expect to sit themselves into an airplane that has one or two latent "quirks" even before we start installing the mods. I'm talking about the effects of long-term maintenance and even issues such as corrosion and vibration which as you know cause grounds to open and shields to degrade. My point is that transient problems can't be used to prove that a problem or a threat exists, even if they hint that there might be one. There's always some other possible cause until you've investigated enough to rule them out.

I still haven't read the reliable source that describes a repeatable process that isolates the specific cause to a 5G antenna. Shoot approaches with the same plane enough times on the same runway with instruments taking detailed measurements of interfering signals. Oh, wait, there ARE planes that do that on a regular basis. The airport flight inspection operators would be the first people I'd turn to for testing the effects of 5G. We would know by now.

GPS jamming is quite different and I am MUCH MORE concerned about that. Especially as I am often concerned with installing new precision approach guidance upgrades in older aircraft. For instance, last month somebody did something that suppressed all GPS signals around DFW for half a day. That's both strange and a threat. It happens often enough that I'm not convinced that it's just the US military putting their own commercial brethren in danger.