- You say the BSCU limits deceleration to 1.7 m/secē. When all three ADIRUs are off, where does the BSCU get the limiting decelaration reference from?
Good question! A tachometer on each mainwheel provides speed, and the BSCU uses the highest value as reference speed in the absence if ADIRU information. There's a pic on FCOM 1.32.30 p2 with some maths formulae which explain it all....
Airbus also say that the probability of a triple IR failure is so remote there is no need for a specific ECAM procedure.
Which leads me to thinking of a suitable braking procedure... as the A/SKID is working you can apply max pedal deflection. Anyone see a problem with that?
TP