There have been a lot of noises about this and
this suggests it is coming in 2014, but the other day I heard from somebody who meets the CAA regularly that it has been abandoned.
That would be great news because the aircraft approval cost is 4 figures, unless you put in the GTN650/750 in which case it is a Minor Mod (EASA) but it is a varying hassle for an N-reg.
There are some airports with PRNAV-only SIDs and STARs but fortunately ATC tends to ignore that.
I never understood it because it is equivalent to RNP 1.0 whereas GPS approach approval is an EASA
Minor Mod and that is equivalent to RNP 0.3. In effect, GPS has caused the bottom to fall out of the navigation market, rendering PRNAV meaningless. This happened ages ago.
Does anybody know any more? I know a number of ATCOs read this site.