1.8 APPROACH OPERATIONS UTILIZING BARO-VNAV EQUIPMENT
1.8.1 Baro-VNAV equipment can be applied to two different approach and landing operations:
a.
Approach and landing operations with the vertical guidance. In this case, the use of a VNAV system such as baro-VNAV is required. When baro-VNAV is used, the lateral navigation guidance is based on the
RNP APCH and RNP AR APCH navigation specifications.
b.
Non-precision approach and landing operations. In this case, the use of a baro-VNAV system is not required but auxiliary to facilitate the CDFA technique as described in 1.7.2. This means that advisory VNAV guidance is being overlaid on a non-precision approach. The lateral navigation guidance is predicated
on the navigation system designated on the chart.
Furthermore Airbus FM says following:
Approach Procedure with GPS PRIMARY
Before starting the approach, check that GPS PRIMARY is available on both MCDU.
If GPS PRIMARY LOST indication appears on ND during the approach, discontinue the approach unless :
‐ GPS is not required and navigation accuracy is confirmed against the radio navaid raw data, or
‐ For RNAV approach not requiring GPS, HIGH accuracy is displayed on MCDU with the appropriate RNP value.
‐ If GPS PRIMARY is lost on only one FMGC, the approach can be continued using AP/FD associated to the other FMGC.
Once again all depends on which approach you're shooting.
