Potential Disaster, 5G and Aircraft 6

[TugboatEng]

Interesting, it looks like the FAA is concerned about 5g interfering with altimeters on many commerical aircraft.

https://www.faa.gov/newsroom/faa-statement-5g

The current restrictions would prevent the use of auto-land as well as landing in low visibility conditions.

 

[Alistair_Heaton]

Can't believe that's the way the rule is implemented, since it basically says that any sod can force a new band to be not usable because their original equipment was designed so crappy that it gets interfered with by anyone regardless of how clean the other person's design is.

Its legacy gear only, so if in its day it was approved to the standards at the time as these rad alts are then it apply's.

At the time it more than likely wasn't crappy design it was normal for the 1960's.

Have a look at the ITU stuff. Its a pretty toothless organisation I believe.

But anyway if it costs the airlines and OEM's any cash which this will do its well worth lawyering up for the cost of the new hardware that can co exist with 5G in the USA. As linked above Japan seemed to have cracked it over a year ago without any fuss or willy waving and no hardware upgrades.

 

[Alistair_Heaton]

And another one that's going to hammer the cargo aircraft.

https://public-inspection.federalregister.gov/2022-01695.pdf

BTW I am searching for stuff on the A220 on the subject and can't find much. Purely for personal interest and further my systems knowledge.

 

[LittleInch]

So what's that list for Alistair?

There's some massive airports on that list...

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

 

[Alistair_Heaton]

That's the list of commercial airports in the USA which have the upgraded systems and approval for carrying out Low visibility approaches which require the rad alt to be operational to perform them.

If the crew elects to do an autoland even if the weather is good that also needs the rad alt.

Basically if the cloud base is less than 200ft or the RVR is less than 550 meters then a low visibility approach is required. But it has a knock on effect because you can't use airports with worse weather than that as alternates either.

RVR = Runway visual range. measured at 3 points touchdown, mid and end.

550 meters is semi skimmed milk doing 140 mph.

That AD though applies to all aircraft operating in FAA territory even if they are not on that list be they commercial or privately run.

 

[davefitz]

I hope the radar altimeter's reading is one input to the data recorder, so that when a crash occurs they can properly blame it on 5G and not the default "pilot error".

"...when logic, and proportion, have fallen, sloppy dead..." Grace Slick

 

[Alistair_Heaton]

yes they picked up the dodgy readings with the Turkish in Schiphol.

But they won't be able to determine why the rad was giving the dodgy reading.

 

[debodine]

At this point in time I have no idea what effect 5G will have on certification testing, but I am curious. I don't get involved at the OEM level of certification testing for an aircraft Type Certificate. But I do sometimes witness and approve testing during a prototype effort for an aircraft configuration change, typically a Supplemental Type Certificate.

Such testing will require operating the newly installed or altered systems while monitoring all other required aircraft systems to show compliance to 14 CFR 25.1431 for immunity to EMI/RFI interference. I am wondering if proximity of the airport to 5G towers, or even possibly maintenance persons on the ramp using 5G phones close to the aircraft might cause us to see glitches in the Radio Altimeter test results or altitude display. This could be caused by signals that come and go intermittently as conditions around the aircraft change (cell tower load varies, or technicians arrive/depart the ramp area or start/stop using their phones).

If it happens, it would be a nightmare to troubleshoot and could lower confidence in the test results if the glitches "heal themselves". Like all persons with experience in troubleshooting, I would always prefer a hard failure to an intermittent that cannot be reliably duplicated.

 

[Lou Scannon]

Like all persons with experience in troubleshooting, I would always prefer a hard failure to an intermittent that cannot be reliably duplicated.

All of my worst troubleshooting headaches came from exactly that: intermittent failures.

"Schiefgehen wird, was schiefgehen kann" - das Murphygesetz

 

[Lou Scannon]

The other very tricky troubleshooting problem is interactions between components, systems or subsystems that were not designed to be applied together in the manner under consideration, which is the case here also.

"Schiefgehen wird, was schiefgehen kann" - das Murphygesetz

 

[Alistair_Heaton]

"heal themselves"

Nothing worse, first sector of 4 you get a fuel tank inerting failure.

MEL it and ops change the plan so the aircraft is in the hanger overnight.

Top of decent on the last sector it self heals. Still in all the aircraft health logs but can't replicate.

At least with the smart probes we don't have 40 meters of piping which can leak when the aircraft is under flight loads and temps and is impossible to reproduce on the ground.

 

[Alistair_Heaton]

https://www.youtube.com/watch?v=Ufux-SSNOPM

Seems like the Ukrainians know how to deal with rad alt overruns

bit of humour but scary.

 

[JohnRBaker]

In the video, they billed that as the largest plane in the world, and while Antonov does produce the largest plane in the world, that one was NOT it. This one is, the An-225:

John R. Baker, P.E. (ret)
Irvine, CA
Siemens PLM:
UG/NX Museum:

The secret of life is not finding someone to live with
It's finding someone you can't live without

 

[Alistair_Heaton]

yep and that thing is utterly colossal. And the cockpit is bigger than the first floor of my apartment.

Got to have a look round it in Kiev they had 7 people in it.

To be fair the 124 is a big boy as well and giving it wellie to dig your self out after over running is certainly not how us westerners would do it.

going out on a limb here but I suspect that it won't have a problem with 5G in fact you could more than likely cook a chicken under its rad alt.

 

[debodine]

I had a chance to internally tour the AN-124 years ago and I am very glad I did. I wish I could get the same opportunity to tour the AN-225. Alistair, good for you for getting a look when you had the chance!

 

[Alistair_Heaton]

it was the amount of fully inflated tyres they carry in the back which amazed me.

 

[dik]

FYI
The An-225's pressurized cargo hold is 1,300 m3 (46,000 cu ft) in volume; 6.4 m (21 ft 0 in) wide, 4.4 m (14 ft) high, and 43.35 m (142 ft 3 in) long.

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

 

[Alistair_Heaton]

And up to 250 tons. Don't have a clue what range that gives it though at that load

 

[dik]

end of the runway?

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

 

[IRstuff]

Interestingly, the A380 has a higher MTOW, but the AN-225 has more wing area, so its W/A is actually slightly lower. at 663 kg/m^2 vs. 680 kg/m^2 for the A380/

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert!

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[Alistair_Heaton]

seems the faa has been beaten into submission and is now going to require all aircraft that can't prove they are 5G tolerant to get modified so they are.