Macn number
Hi,
First of all I must point out that I'm not in any position to speak authoritatively on this subject (as a mere 'modestly' experienced A320 F/O :-) )
However, my two cents worth is that the Mach no. indication would/should not be available in this scenario given that Mach no. is an expression of the aircrafts IAS(CAS I imagine, to be pedantic) relative to the local speed of sound.
So if you deprive the Air data computers of (all) the pitot information then it can't know its airspeed hence it can't can't know how close it is to the local speed of sound hence it can't compute or display the Mach no.
I stand to be corrected of course! :-)
I'm also very interested to hear the replies of the more learned contributors.
Regards,
Emerald Flyer.