I am currently flying an Airbus out of my base that has the RDMI inop. It has been thus since we got the thing, and is likely to remain 'thus' for the forseeable future. When I say 'the', I mean 'the only' RDMI because this particular 321 only has 1 fitted. I'm pretty sure that most 32x series only have 1, if not all. Anyway, this is in accordance with the MEL.
If both the FMGSs fail, I would like to know how I could continue a SID or a STAR, hand-flown or automatic, in this situation. If all the screens fail, I would like to know how to do the above as well. As for continuing to fly on airways... don't make me laugh; I could do it on a Boeing, but not anymore.
The simple answer is... I can't. I'm now reliant on vectors and / or my standby instruments (which are glass... they can't fail, can they ?! see below....)
The RDMI is tuned from the FMGS anyway, so perhaps if the FMGS fails, I can't tune the thing anyway... can't find the answer in the FCOM, so it will be a 'can we try this ?' at the next sim.
The underlying argument seems to be - "When it all goes wrong, you should have the skills to be able to continue safely."
I'd like to add another argument - "When it all goes wrong, you should have the KIT to be able to continue safely." I'm not sure I do with the WonderBus... my operator has experienced an all-screen failure (including standby instruments) on this type and luckily it was VMC with subsequently no drama.
Having said that, it does make you look like an airborne god sometimes... FDs off, 'hand-flown' (chuckle) VOR approach into IBZ... on the rails, 3.2 degree continuous slope. Not because I'm great, but because the aircraft gives you tools that other types don't have. I don't fancy my chances on anything else after a few years on this though....