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.