If you are operating the A320 family you should be familiar with the fact that the required equipment to start an RNP approach is listed in PRO-SPO-51. ( which happens to be : One FMGC ‐ One GPS ‐ Two IRS ‐ One MCDU ‐ One FD ‐ One PFD on the PF side , Two FCU channels , 2 NDs ) .
My question is the following : Why does airbus use the wording “start” (minimum equipment required to start RNP APCH operations) ?
Is there an implication that once you are in the procedure and you lose one of those systems you could continue under some circumstances?