As you know, ICAO general rule in Europe is:
- RNP1 for Terminal area (SID and STAR)
- RNP5 for Enroute
are you sure? BRNAV = RNP 5 equivenant PRNAV = RNP 1 equivelant but they are not the same and PRNAV is not widely implemented.
You are mixing apples and oranges a little.
From the link above:
Viewed from a European strategic perspective, the application of P-RNAV in ECAC Terminal Airspace is to be viewed as a pragmatic step towards RNP RNAV application which will form the basis of RNAV terminal area procedures in the future.
a step towards.