Standby Gains
CJ: I agree with Rob21, and I previously mentioned that the Viper had a "standby gains" function for just this reason - bug in the pitot tube(s), ice, physical damage ( and we had one accident from a huge pelican ripping away the radome and air data sensors).
Granted, we had a much greater speed range and less worry about mach "protection" , but the fixed dynamic pressure ratio value was a bit above normal cruise CAS/mach. It was much lower with gear down, as the stick would have seemed too 'stiff" for the amount of control surface movement we were demanding and the confusers would have applied less movement for the flight condition.
So this seems a very straighforward reversion function and should not completely eliminate the basic attitude control functions of the A/P. Lose the pitot system and the STBY GAINS lite comes on. Hmmmmmm, no big deal and the jet just seems "stiffer", more sluggish for "x" control stick input. The system could even use last known values, but most engineers would prefer a fixed value in non-volatile memory as we did. This implementation would also keep the "mach" protections outta play, but the crew would know this when the warming lite illuminated.
Further, there are probably pressure functions in the control actuators themselves that "limit" them as to rate and amount of movement depending upon actual forces exerted upon the control surfaces.