They are approved for non-precision RNav approaches.
OK, now it makes sense.
Your FTO has got its fleet approved to fly GPS/RNAV approaches
That is an EASA Minor mod - easy. The procedure is similar to BRNAV and has similar equipment (annunciator location, etc) requirements to BRNAV. Similar tests for VHF interference, etc.
Surely the approval for approaches (RNP0.3) will also cover PRNav (RNP1.0)?
That kind of progressive thinking will never get you a job at Eurocontrol. As you have just discovered, this king has no clothes, and has not even had a pair of pink underpants for more than a decade.
Of course PRNAV is total bollox, when you can get a GPS approach approval.
But you must be a good citizen and think of all those poor failed ISO9000 quality managers who are pushing PRNAV. They have families to feed.
As regards a serious answer, I think it is in several parts. Your GPS needs an LOA from the mfg and not all IFR GPSs (all of which are OK for a GPS approach approval) have this LOA. Then, under EASA, it is a Major mod (4 figures). It is an AFMS under the FAA which is also a Major mod, done with a 337, but the FAA has a straight process for flight manual supplements (well, in the USA, anyway...).
N-regs also need an EHSI for PRNAV, if doing it today. G-regs don't.
You should come to more PPL/IR Europe meetings, IO540. Weren't you at Cambridge when Paul and Anthony explained how they got the PRNAV certification?
That's two planes. I haven't been to the meetings for a few years.
I gather from someone in the business that they got in before the EASA clampdown. Last year a friend had a major (£30k?) avionics job done, with PRNAV paperwork, but the allegedly promised paperwork never turned up, and the last I heard from him was that he was still waiting for it but then he died - around middle of 2010.
So there are probably just two in Europe; maybe a few more around. I know loads of European IFR pilots and none of those I know appear to have the masochistic tendencies required to do this now.
It used to be quite doable on the N-reg, before the NY IFU washed its hands of avionics 337s. We both know one chap who got his plane done, in the very early days before anybody knew what this was about, by burying the FSDO under so much paper they rubber stamped it all just to be able to breathe again. Now, you have to use a "different route"...
The basic point however is that it is irrelevant to IFR flight. It's a pure job/activity creation scheme.