The approach may be broken down into phases, with the response to a failure determined by the phase. The phases are:
A reversion to a lower category of approach can be made as long as the required minimas are available, all ECAM actions are completed by 1000ft and the reversion is briefed.
Go around for any master caution, master warning, mode reversion or instrument flag. A new approach to higher minimas may be attempted once rebriefed.
Go around in the event of an AUTOLAND light.
LAND should be displayed at 400ft RA. If it is not displayed at 350ft, go around. In addition, ILS course should be checked by 350ft. If it is incorrect, a reversion to Cat II minimas followed by autopilot disconnect by 80ft and a manual landing is permissable.