A33Zab,
Thanks for your clarifications about the BUSS and the law reversion.
BUSS is more than a replacement of pitch/thrust tables.
I just quoted directly from an Airbus safety article and tried to keep it simple. The article statement read:
In order to decrease the crew workload in case of unreliable speed, Airbus has developed the Back-Up Speed Scale (BUSS) that replaces the pitch and thrust tables.
The article was written by Airbus' Flight Operations Engineer and gives some other details such as AOA information being provided through the IRs and not through the ADRs which enables selection of all ADRs off without the loss of stall warning protection. Then, if and when the crew does shut off all 3 ADRs, the Back-Up Speed Scale replaces the PFD speed scale on both PFDs. Also, GPS altitude replaces the Altitude Scale on both PDFs. So then, keeping the pointer in the green (out of the amber or red) is the goal to be achieved by adjusting thrust and pitch thereby keeping above stall speed and below maximum structural speed. The BUSS speed scale was shown with the statement, "Fly the green."
The author concluded with this statement: "In case of any doubt, the pilot should apply the pitch/thrust memory items and then refer to the QRH to safely fly the aircraft and to positively determine the faulty source or sources before eliminating it or them."