A320 G sys

[Higgs boson]

In case of G sys Lo pr, wheel is listed as a secondary failure. Does this mean nose wheel steering is not available?

[8314]

You might have troubles changing the status of your undercarriage. That’s what it’s telling you. N/W is under INOP SYS.

[vilas]

Originally Posted by Higgs boson

In case of G sys Lo pr, wheel is listed as a secondary failure. Does this mean nose wheel steering is not available?

Wheel is for Autobrake and normal brake not available. Nose wheel stearing is on yellow system.

[8314]

[QUOTE=vilas... Nose wheel stearing is on yellow system.[/QUOTE]
Maybe on your fancy new fleet! 😬

[vilas]

Originally Posted by 8314

Maybe on your fancy new fleet! 😬

Even on new fleet where NWS is on Y system wheel is shown in secondary failures. So it cannot be for stearing.

[Higgs boson]

ok. Thanks

[Higgs boson]

Originally Posted by 8314

You might have troubles changing the status of your undercarriage. That’s what it’s telling you. N/W is under INOP SYS.

NWS is inoperative only in the case of Y sys Lo Pressure

[8314]

Depends on your MSN.

[320.jockey]

It must be the inoperative normal braking and autobrake. I looked in our OMs, as we have both generations with NWS on G or Y hydraulic.
Only in case of G SYS LO PR *WHEEL is listed as a secondary failure. Not in the case of Y SYS LO PR, no matter which system supplies the NWS. And while it is true that you will have to extend the gear by gravity extension and L/G RETRACT is inop (as both indicated on the STS page), there is no indication of that on the WHEEL SD page. Only NORM BRK, AUTO BRK and STEERING are displayed in amber (and because there is never a *WHEEL secondary failure with Y SYS LO PR, it can't be the STEERING part). As you will have to analyse the associated SD in case of a secondary failure during the ECAM actions as per "Handling of ECAM" it can't be the gravity extension or inoperative retraction, because there is simply no indication of that on the wheel page.

Why only the braking part is classified as a secondary failure and not the steering I don't know...

[rosteredgirl]

So at the end what should be the answer to this question, because I am bit confused with everyone response ?

Thanks

[Ollie Onion]

Originally Posted by 320.jockey

It must be the inoperative normal braking and autobrake. I looked in our OMs, as we have both generations with NWS on G or Y hydraulic.
Only in case of G SYS LO PR *WHEEL is listed as a secondary failure. Not in the case of Y SYS LO PR, no matter which system supplies the NWS. And while it is true that you will have to extend the gear by gravity extension and L/G RETRACT is inop (as both indicated on the STS page), there is no indication of that on the WHEEL SD page. Only NORM BRK, AUTO BRK and STEERING are displayed in amber (and because there is never a *WHEEL secondary failure with Y SYS LO PR, it can't be the STEERING part). As you will have to analyse the associated SD in case of a secondary failure during the ECAM actions as per "Handling of ECAM" it can't be the gravity extension or inoperative retraction, because there is simply no indication of that on the wheel page.

Why only the braking part is classified as a secondary failure and not the steering I don't know...

not sure that is correct, the secondary failure points you to a system that is affected by the primary failure, it doesn’t relate to the name of a systems page I.e. if there is a secondary failure in the brake system it will list ‘brakes’ as a secondary failure and no such system page exists. The ‘wheel’ secondary failure is telling you that the Green System is your extension and retraction system and without it you can’t extend or retract the gear in a normal manner which is a secondly failure in the ‘wheel’ system. Simple as that.

[320.jockey]

Originally Posted by Ollie Onion

not sure that is correct, the secondary failure points you to a system that is affected by the primary failure, it doesn’t relate to the name of a systems page I.e. if there is a secondary failure in the brake system it will list ‘brakes’ as a secondary failure and no such system page exists. The ‘wheel’ secondary failure is telling you that the Green System is your extension and retraction system and without it you can’t extend or retract the gear in a normal manner which is a secondly failure in the ‘wheel’ system. Simple as that.

Well, what we are talking about is just the technicality of how Airbus programs secondary failures. The exact rules of the ECAM programming which primary failure is linked to which secondary failure using which system title (e.g. F/CTL) is not stated in the FCOM. There's just a deduction possibile if you look at all the primary failures in the abnormal section and check their associated secondary failures and system titles. If anyone has some other manuals with deeper information about the programming that's another case, but if we only have the FCOM, let's deduct:

In our case we are talking about the *WHEEL secondary failure to the G SYS LO PR. It will lead to a popup of the WHEEL SD page during the handling of the ECAM (check next time in the sim or watch a youtube video on G HYD failure handling in the sim, there are some). So my guess it's associated with something we can analyse on the WHEEL SD page. The following is indicated as inop on the WHEEL page: NORM BRK, AUTO BRK and possibly STEERING (as well as spoiler pairs 1 and 5). In my previous post I showed why it can't be the STEERING (and also not the spoilers, for the same reason), no matter which aircraft generation.

Your guess is that there should be *BRAKES listed if the secondary failure is part of the BRAKES system and that's why the *WHEEL refers to the operation of the landing gear. However, the correct ECAM system title of the landing gear (including anything to do with its operation) is also not "WHEEL" but "L/G" (for example "L/G GEAR NOT UPLOCKED"). So, my point and guess is that as the WHEEL page will popup, it is linked to the NORM BRK and AUTO BRK.
Maybe another point that supports my theory is that if you look up NAV ADR 1+3 FAULT there is no *WHEEL secondary failure indicated on ECAM, even though the normal gear extension is not working. That hints to the normal gear extension never being a secondary failure.

As said, it's all only deduction from my side, but the only logical and systematic pattern for me if you look at the other primary failures out there.
Does it matter for dealing with that failure? Probably not, as you'll figure out what all the inop systems are when looking at the STS.