Starbear - Thank you for that clarification. I am looking at our QRH page IV, Immediate Action Section it states the following:
1. IF the Safe conduct of the flight is impacted:
a. AP.......................................................... .........OFF
b. FD.......................................................... .........OFF
c. A/THR......................................................... ....OFF
d. if below THR RED ALT .................................. pitch 15 / TOGA
if above THR RED ALT and below FL 100..........Pitch 10 / Climb
If above Thru RED ALT and abvoe FL 100.........Pitch 5 / Climb
Then there are conditions for flaps extended during approach.
Immediate actions complete go to page 72.
Page 72 leads to a series of tables. We fly all 319, 320, 321 so there are a lot of tables. These table have pitch and power settings for altitudes from FL 100 up to FL 400. Interpolation is required as the altitudes in the tables are FL 100, 200, 300, 350 and 400.
The original poster made this statement: In unreliable speed (all ADR's affected) you have to descend to FL250 to enable BUSS.
The only place where FL 250 is addressed in our QRH is at the latter end of the procedure and it has the following note:
If on an aircraft equipped with BUSS
When above FL 250
a. One ADR .........................................Keep on
b. TWO ADR pb's..................................Off
[this prevents the flight control laws from using two coherent but unreliable ADR data].
I believe that BUSS would still be available via one ADR above FL 250, from my reading of our QRH.