FAA ADs re 5G interference
 

International Federation of Air Line Pilots' Ass'ns (IFALPA) has issued Safety Bulletin: "Aircraft Operations and Radar Altimeter Interference from 5G" (21SAB16). It is based on the Safety Alert issued by ALPA-International under the same name, and contains links to access the FAA Airworthiness Directives.

21sab16-aircraft-operations-and-radar-altimeter-interference-from-5g.pdf (ifalpa.org)

Not an AD but a Special Airworthiness Information Bulletin (SAIB), two different animals

As noted in the IFALPA paper (to be read until the end), there is the SAIB and there are two ADs (one for aircraft and one for helicopters): 2021-23-12 and 2021-23-13.

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From The Register .....

https://www.theregister.com/2021/12/..._interference/

"The change could affect some 6,834 airplanes and 1,828 helicopters. The cost to operators is expected to be $580,890."

Er, $67.06c per airframe? Sum mistake Shirley?

FAA cost estimates in AD's tend to be pretty optimistic. Plus, the costs are only listed for US based aircraft.

FYI: there's 2 separate ADs. Your missing the $155,380.00 to comply with the helicopter side which equals the $85.00 per airframe as stated in the AD. So the total for all aircraft is $736,270.00. Here's the actual AD references where you can submit a formal comment as well if you like.
https://www.federalregister.gov/docu...us-helicopters
https://www.federalregister.gov/docu...gory-airplanes

Just to be clear - the cost to operators some have mentioned above reflects the cost to update the paper or electronic AFM with a new page containing the new Limitation. It does not reflect the costs of the cancelled flights or diversions or Missed Approaches and Go Arounds or the costs of the new equipment (Radar Altimeters and Software) we'll all need to purchase down the road. That's going to be closer to a $1 million per a/c I expect before more adaptable Rad Alts can be developed and installed.

WillowRun 6-3,
Apart from marking a major blow-up between US Federal government agencies and thereby providing a potentially entertaining “pass the popcorn” opportunity for those of us outside the USA, does this escalation in inter-agency hostilities have any collateral benefits for US airlines?
For example, can an airline now sue the FCC because it will be able to demonstrate an actual loss (e.g. “We can no longer schedule flights to XXX after dark or in bad weather”) whereas before they could only point out a potential detriment?

I'd like to say I anticipated this question - though I didn't. So I'll start at the end, and work back toward the start.

For an airline to file a lawsuit against the FCC, among the issues I'd want to hammer down is, to what extent is it realistic to anticipate that a federal district court (presumably where suit would be filed) would even have the competence to deal with the technical issues? While it is true that federal district courts do see litigation involving arcane and complex subject matters, these are subjects which get presented to the courts with some frequency, and do not present new technology just now entering service. (It's not perfect as a comparison, but consider what a hash Congress has made with regard to establishing regulatory frameworks for social media.) And in complex arcane matters before federal courts at present, I think most veteran litigators - and especially their clients - would concur with the assessment that the results of those cases leave a lot to be desired. It's one thing to get the statute of limitations analysis, where equitable tolling arguments are made, correct - quite another to resolve dueling expert witnesses with regard to proper statistical techniques for assessing results of Phase III clinical trial of a prostate cancer pharma product. So I would question whether the court, in perhaps a novel turn of a standard phrase, is a court of competent jurisdiction.

Of course an airline might go ahead and sue as part of a political effort by airlines. Or for some notion of public relations points. On the other hand, what actual claims could be made -- abuse of discretion under the Chevron deference-to-agency interpretation of statutory provisions? - I don't know. I mean, I don't know the answer already, plus I'm not planning on drilling into it (uh, absent an actual client, that is), plus there's more to respond to in your question.

So this is a "blow-up" between federal agencies?, "escalating inter-agency hostilities"? Well, it's really not. Because as you know the FAA is "housed" within the Department of Transportation, which is headed by a political appointee. The current Secretary's background for his appointment and confirmation by the Senate - apart from some slick presidential primary campaigning which of course is utterly meaningless - is that he was Mayor of a small city the apparatus of which is dominated by a major private university (Notre Dame). So in refusing to let cellular providers take control, the FAA has stepped into the breach. And it was able to do so, in major part, precisely because the Department in which FAA is situated is headed by a Secretary who really does not have much knowledge whatsoever about, you know, how things work (and don't work) up front, that so-called pointy end of the airplane. Just my view, not an official or verifiable opinion, of course.

But your post did more, for it reminded your loyal forum SLF/atty of how much I enjoyed popcorn during some several months when I held a volunteer gig (sort of) at Chicago O'Hare. And to return the favor, and since the first real blow-up was, of course, in 1966 and directed by Michelangelo Antonioni and produced by Carlo Ponti - for your enjoyment of a non-U.S.A. film to accompany that popcorn:
Blow-Up (imdb.com)

oops...Missed that until I got into the office and saw the ADs.
Anyhow, the drive behind the AD is a simple change to the flight manual IF there is a NOTAM out on the problem.....
My guess is the number of NFF removals of RA's is going to go through the roof, or worse, real problems are going to be signed off as 5G issues. What a mess

There might be downsides. I don't know who sits closer to the president in his cabinet meetings or state dinners. But if the FAA perceives itself to be the possible loser in an administration d:mad:k-swinging contest, they might not appreciate getting dragged into this fight.

Amazing state of affairs.

LRRA are pretty much essential equipment for approaches below CAT I minima. So, yeah, that's a bit of a nuisance. At least the weather in the USA, like JFK, IAD, ORD never goes bad, It's all like California, or Queensland, beautiful one day perfect the next. Same for CDG, LHR, EDDF etc in the EU. Great.

I seem to recall once we were told how GPWS works, a mandated system... so, presumably the GPWS escape manoeuvers that ensue from the erroneous ramp-up of LRRAs will be enjoyed by one and all. Going to be most entertaining in a stack as someone gets a false GPWS "pull up" and bobbles through the pack above.

Will the FAA send out a revision to this lunacy with an edict to disconnect the LRRA input to de-activate GPWS systems? that would be something that would look bad on your resume after the first pax plane plants itself in the sod with a crippled GPWS system. EGPWS is faaaantastic, but GPWS is still mandated by the FARs, but perhaps it now gets partial retirement by EGPWS... except that multiple modes of GPWS are not provided by EGPWS... hmmm. Maybe it is just software, just like the change from 7.0 to 7.1 which was just software at about $100,000 per box, after all it's not like Honeywell to miss a chance to fleece the industry.

At least GPS is a fine basis for all safety systems, except, in the last 18 months around the SCS region, where the dispute over 9 line vs every other nation in the world seems to curiously result in jamming by persons unknown of GPS signals, taking out independent certified GPS systems of different design, OEM, op software. That is a bit untidy for EGPWS systems. Remarkably, there are some systems that are not certified that continue to work reliably and also give EGPWS guidance. Neat that the certified system gets jammed and messed by unknown jammers with disregard for civil aviation, yet the uncertified systems work like a charm.

Glad to see that the FCC and FAA had everyone's backs on this one.

I think it’s “who sits closer to the moneyed interests”, which might be the same, I don’t know.

Suggest all Ops Managers, and all flight crew that have a desire to have GPWS send their seasons greetings to:

Brett Portwood, Continued Operational Safety Technical Advisor, COS Program Management Section, Operational Safety Branch, FAA, 3960 Paramount Boulevard, Lakewood, CA 90712-4137; phone: 817-222-5390; email: operationalsafety at the good ol' FAA dot GOV.

At this time, the constraints are to remove SA CAT I/II/III, Autoland, EVS and the like at the NOTAMed airports, but your GPWS system is also compromised, so expect warnings to go off. Just what you want is a warning system that goes off randomly, it results in a resistance to response that may affect real warnings. The insanity of this nonsense is breathtaking, the only realistic defence is to have VMC operations only below safety height, which should pretty much stop all turbine traffic in the east of the USA that may be subject to this NOTAM in the season of cheer... or risk repetitive false warnings resulting in resistance to response in real cases, that's what humans do. We are good at learning workarounds, and those workarounds tend to become pavlovian heuristics that have unintended consequences. Of course, Collins, Honeywell and co, can always come up with new LRRAs that operate on a new band, that shouldn't take more than 5 years to push through, and about 25K per aircraft, 3 times that for Boings and Airbusses etc...

Wish that the FAA and FCC had kept with just making a stew to go with yoghurt and tabbouleh instead of becoming amorous with the goats.


FAA 2021-23-12 DOCKET


:}


At least IATA and IFALPA understands the issue, even if it was subsequently disregarded in the FAA AD...

IATA PROBLEM STATEMENT 27 NOV 20 MONTREAL

List of potential equipment failures:

Interference to RA operations can affect:

1. Autoland functions: This is particularly critical in low visibility auto approach like Cat II or III conditions. Pilots cannot conduct CAT II and III approaches if RA is malfunctioning.

2. EICAS/ECAM: Nuisance warning after take-off or during approach which will distract crew from their tasks at hand. This will lead to deterioration of operational safety levels.

3. False or missing GPWS alert: Anywhere in proximity to ground, this could inhibit some functionalities of the TAWS (Terrain Alerting Warning System) reactive modes which would remove a safety net in case against CFIT (Controlled Flight Into Terrain). Additional distractions for crews from tasks at hand, – “too low gear” and “too low flaps”, “don’t sink”,” terrain and pull up warning” and other alerts. A big concern is GPWS not triggering an alert when it should have done so, because of interference which can result in CFIT event!

4. Unreliable instrument Indications: This could contribute to an increased number of hard landings because of errors in automatic altitude indications and voice announcements.

5. Abnormal behaviours in Automatic Flight Systems: a. Autoland system b. Flight Control Laws (e.g. failure to transition to Flare law resulting in a higher than expected pitch on the flare; Retard function, etc.) c. Auto-throttle automatic stall protection. d. Auto Speedbrake deployment



Remember, your busses, big 'n little, use RA for determining control laws.... watch this space...


In spite of the perceptiveness of IATA and IFALPA in NOV 2020, we get 5G on the same band as the RA's???? WTF!

testing
 

Hi, would anyone know what the FAA action is based on ? Did they test actual equipment, i.e. radio altimeters near 5G antennas, or did they study the literature which says there is a possibility that there might be trouble ? I am hoping that tests have been conducted to get to the bottom of this ....

I'm a PNT technologist not a pilot and only comment (occasionally) on technical matters. I used (a very long time ago) to be an FAA qualified Aircraft dispatcher, There was a US PNT Advisory Board (PNTAB) meeting in Washington last week at which Hon. Jeff Shane, IATA Representative & PNTAB Member gave a presentation on recent FCC decisions and implications. I can't post a link but the presentation is here and quite informative... perhaps someone else could post/share for me. The presentation is available to download on the gps.gov website under the PNT Advisory Board Dec 9-10. , Dec 09 5.15-5.40pm.5th Meeting
December 9-10, 2021

To add perhaps some significance to one of the above posts, Jeff Shane is General Counsel of IATA - in the realms of public and private international air law, positions for attorneys working as lawyers don't get any more significant than that. (Correction: Mr. Shane retired as GC summer 2020 - but still.)

Here's the link to the agenda for the PNTAB meeting recently, in case it might be of interest.
GPS.gov: 25th Meeting of the National Space-Based Positioning, Navigation, and Timing Advisory Board - December 2021

(Also, in my previous post, I was somewhat tentative in arguing that the FAA had stepped into what it saw as a kind of power vacuum. It appeared that the cellular providers had been able to out-lobby, out-money, and out-influence the voices of and advocates for integrity of the aviation safety ecosystem. And that with the start of this White House administration, its Secretary of Transportation - lacking as he does any operational experience or insight with regard to aviation operations or safety, or big-league interest infighting in Washington (despite his other fine qualities) - had emerged as a . . . . bystander. So rather than cede the playing field to the cellular providers, and knowing that the current DoT leader isn't a heavy-hitter like Liddy Dole or Elaine Chao, FAA took the bull by the horns. I think, with the explanation of just how bad the risks to operational aviation safety really are (THANK you fdr and others), this power-match map looks even more accurately drawn.)

With U.S. Permanent Rep to ICAO Council, Ambassador Chesley "Sully" Sullenberger having now been sworn in to his office, maybe something different can take shape. Hope springs eternal.

Airbus Vs Rad Alr Vs 5G
 

A bigger issue ,as far as I can see, is that even in perfect weather any, sustained disturbance in the RA signal on the Airbus could cause a downgrade in the control laws. Definitely not something you want at the bottom of an approach in a windy day.........

Just to be clear, they are not in the same band. They are in adjacent allocations, with a small guard band in between.

For interference to be avoided, two conditions need to be met. 1) the 5G equipment must not radiate significantly outside its allocated band, 2) the airborne equipment must must not be significantly sensitive to transmissions outside its allocated band. And of course the same conditions apply in reverse.

It is the task of frequency administrations to specify operating limits accordingly - and this must be done on an international basis.

So, if a Telecom needs to put 5G tower under approach path, they are free to do it, and FAA will merely tell everybody that from the date of installation, CAT I / II / III is effectively not available at this airport anymore. I always thought that such action (interfering with A/C navigation equipment) is something that terrorists would do, but now this is perfectly legal ??!! :( :yuk: :eek: World going insane.

The national radio regulator can impose whatever conditions it sees fit on the cellular operator's licenced operations in order to protect other services. So it could in theory say that there will be no 5G operation with x km of every airport.
Naturally the operators will resist this strongly as it would create holes in their service coverage (and airports are major concentrations of mobile radio use.)
I'm not party to internal US affairs but this would seem to be an issue between FCC and FAA, each being subject to different political pressures.

But again this is an international issue and other countries may treat it differently, within the International Radio Regulations to which each country subscribes.

That's what Canada has done.

Hi, that´s cool...but does it help the helicopters that are flying low everywhere ?
Don´t know.

• a national antenna down-tilt requirement to protect aircraft used in low altitude military operations, search and rescue operations and medical evacuations all over the country

Canadian Source document is here

Decision on Amendments to SRSP-520, Technical Requirement for Fixed and/or Mobile Systems, Including Flexible Use Broadband Systems, in the Band 3450-3650 MHz - Spectrum management and telecommunications

That's interesting considering the 5G signal is beam forming (with a couple of lobes near the antenna). Perhaps they mean "software" down-tilt but I don't know if the 5G tech is that far developed. Theoretically it should be possible to fix this issue in software for antennae located near airports as it's all just crazy mathematics anyway.

As someone who has worked with the greedy mobile telecoms, I can assure you they will fight tooth and nail to maintain their market advantage, but they also understand liability too well so I am pretty sure this whole issue was unforeseen by them as it takes years and much expense to get their wares out to market, and now the bureaucrats have been left to sort it out the only way they know how.

Perception:

So the guy in seat 1A decides to text the cab company on his new 5G phone while on finals to 27R.
The potential for this scenario must be much higher and though the transmission is at a lower power, close proximity to the goon show up front should have resulted in a more terminal arrival.
Are instances of equipment degradation more than is reported?

IG

The classic cellular base/tower has antennas with a downtilt to limit the interference potential to other cells. However this will not always be the case depending on local topography.

As for the guy in 1A, his phone will not be using the new frequency band if it cannot receive a signal in that band. It may still be using 5G on a lower frequency band, but the interference potential is due to the frequency of the transmission, not the modulation method. 3G or 4G could also cause interference if on the 'wrong' frequency. Also bear in mind that the GPWS antenna is pointing downwards, so relatively immune to signals from inside the plane.

Thanks,

I should be relieved but somehow I think the thought will cross my mind at the wrong time - :eek:

In the US, no. There appears to be more issues with the rotorcraft side given a number of approved helicopter approaches operate in prime 5G territory and especially in the GOM. With plans to expand 5G service to over 50,000+ square miles of the GOM this could negate most of the OSAPs used for deepwater ops as they require an operative radar altimeter. And given the only place to put 5G towers is on the same platforms the helicopters operate it will definitely cause some issues. Time will tell.

Hm.... so, what about testing ? Aviation Week shows pictures of test-chambers for satellites and military antennas. Is it possible that a bit of time in such chambers could be booked to see what happens with real equipment ? Not good to do the testing in the wild outdoors....the city-canyons and so forth.

FYI: this issue didn't simply arise when the ADs were released. The 5G/radar altimeter issue has been under scrutiny for some time now so there are a number of studies out there. Here's one presentation released last year. Time will tell which direction it will take but the implications will be global especially on the heavy plank-wing side. But from what I see there is currently no cheap/easy aircraft operational solution at hand for this issue at least on this side of the pond.
https://www.rtca.org/wp-content/uplo...Altimeters.pdf

Great presentation. I live in Europe, and things are a bit different here. Found this compact explanation on the web: https://bit.ly/3m916uq So, our EASA is a bit more relaxed than the FAA. However, I think they shouldn´t be. Euro-Airlines are flying to the US, on occasion :eek: and the telecoms industry here isn´t going to stand still in their efforts to get products to market.

From informal contacts with the UK regulator OFCOM, it seems their present attitude is not to panic but to keep a close watching brief on the situation.

The four UK cellular operators are busy building up their 5G networks, but as far as I can see none of them are yet operating in the 3.5 GHz band around e.g. LHR or LGW. This could of course change at any time as they compete to gain value from their licence investments.

OFCOM have also been consulting on possible new uses within the 3800 - 4200 MHz band which is primarily used for satellite services. This of course is immediately adjacent to the air radar band.

I'm not sure I would say busy. The four UK networks have been struggling to roll out 5G - UK wants to be a market leader, but government meddling has broken the UK market. It is impossible to say whether the lack of 5G midband is due to airports, because they have not got there yet, or simply in the too hard to tick box. Some of the in-airport coverage is also delivered in a very bespoke way, which I suspect will take time to sort out.

BBC report today

Boeing and Airbus warn US over 5G safety concerns

https://www.bbc.co.uk/news/business-59737194

At least they're talking
 

Airlines for America and two other major trade associations have announced that they're trying to resolve the 5G service introduction issues (Aerospace Industries Ass'n and Cellular Telecommunications Industry Ass'n).

link to announcement:
Statement from A4A, AIA and CTIA – Airlines For America

"WASHINGTON, DECEMBER 22, 2021 – The following statement was issued today by A4A, AIA and CTIA:
We are pleased that after productive discussions we will be working together to share the available data from all parties to identify the specific areas of concern for aviation. The best technical experts from across both industries will be working collectively to identify a path forward, in coordination with the FAA and FCC.

Our belief is that by working collaboratively in good faith on a data-driven solution, we can achieve our shared goal of deploying 5G while preserving aviation safety."

real tests 5G vs. helicopter ??
 

Hi, I found this: https://www.iliad.fr/en/actualites/a...-drisquage-124
In French, dated 3/09/2021 : https://www.universfreebox.com/artic...quage-de-la-5g

Looks like the French did at least a bit of testing. Don´t have more details, but the movie makes a good impression that makes me ask for more of the same, maybe different helicopter, different 5G installation, and, of course, fixed wing aircraft.

Unfortunately that test - or at least the report of it - is of no use without a mention of the frequencies that were used for the 5G transmissions. Were they in the new band 3.6 to 3.8GHz* which is of concern due to being nearer to the aeronautical allocation, or in the lower cellular bands e.g. 2.6GHz?

It is the potential conflict from nearly adjacent frequencies that is critical. 5G cellular in the lower bands, which has been in use for some time, poses no risk to airborne operations.

* individual national allocations may be different.