I recently tried a self made scenario with several hydraulic issues. To be more specific: R system both EDP and demand pump failed and a leak on the C system; thus Hyd press sys R + C EICAS message posted and NNC handled.
I was suspecting to have no nose wheel steering available after landing rollout but surprisingly it was.
To sum up my understanding of the system - NWS is supplied by the C/Reserve hydraulic system which has its reservoir below the 'normal' C fluid level and is driven by elec C1 main pump (which I have failed as well to test behavior)
As both C (including reserve) + R hyd systems were inop the BRAKE SOURCE annunciator was lit meaning only brake accumulator was remaining.
Shouldn't in this condition the steering be inop as well as I cannot find a pressure source for it - or am I missing something, or is this simply a FSX limitation?
Furthermore the Hyd press sys C NNC does not mention the steering under inop items. Could you please enlighten me, as i do not understand where magically the system is supplied from :unsure:
Unfortunately there's no further info on the FCOM I could find.
Thanks for taking a look and sharing your thoughts!