Originally Posted by
Jhieminga
Looking at this, any equipment with RNP APCH capability is also capable to use the 'lower' RNP categories.
That's a reasonable rule of thumb, but is not strictly true, as some of the nav specs with higher numbers have other requirements beyond accuracy/integrity. An RNP APCH aircraft is not, for example, always (or even usually) certified for RNP 4, as the latter has requirements for redundancy.
If you don't have the full PBN capabilities available in a specific aircraft, it would not keep you out of a certain piece of sky, but it would keep you off the specified procedures and force you to use other routes/approaches.
Exactly.