A320 : roll out guidance or control system inop.

[C.M]

On an CAT2/3A approach the mid point RVR may be 75m minimum unless the roll out guidance or control system is inoperative, in which case the mid point point RVR should be minimum 125m. On an Airbus which failure cases would pertain to this case? (Except the NWS which is the obvious one)

[EGPFlyer]

You also require one BSCU and antiskid system.. there are also limitations on rollout on a contaminated runway.

[C.M]

Yes , to expand on what you mentioned, one BSCU system ( the other being inoperative) still qualifies you to use a mid RVR of 75m. If you were to lose both BSCU channels the ECAM that will pop up will be ‘BRAKES A/SKID NWS FAULT’ so again it brings us directly to the unavailability of the NWS system. I’m not sure however if antiskid is related to what we are discussing (roll out guidance or control systems inoperative)