Hi jmarkows. That question opens a Pandora’s box!
The phraseology and naming of approach types for the equipment has changed several times during the past 25 or so years. It doesn’t help that the USA have their own designations and that the 146 did not use the UNS 1. Normal equipment fits used to be Trimble or GNS, GNS-X, GNS Enchanted. The Universal SCN 1001.X system raised the bar by introducing certification that improved the RNAV capabilities and introduced RNP capability AND Automatic Dependent Surveillance.
I have used versions of the UNS 1 on other aircraft. As with the GNS-X it was capable of what used to be termed BRNAV - that is point to point NAV using GPS input along airways, SID, STARS. The UNS I’s that I used was also capable of VNAV approach too, but there were limitations - but don’t ask me what they were - not quite ILS limits though.
But it’s not just about the FMS type as to what the aircraft is capable of. There is also the requirement for integration and certification with the aircraft type, pilot training, and company approval.
I would suggest that the equipment would be capable ‘in simworld’ of airways, SID, STARS and possibly lateral navigation such as an overlayed VOR/NDB/LLZ approach with vertical profile flown as a continuous descent approach (CDA) using V/S mode.
BTW, you mention RVSM in passing. I think only one 146 is operated as RVSM capable. The primary reason for this that the type (apart from the above mentioned aircraft) is certified for 30,000 (original aircraft delivered to Australia is 31,000). Getting there is a struggle at high weights and temperatures! Went there a few times for the tailwinds (pre RVSM days) and I don’t think we saw more than 210 kts IAS until descent… Oh happy days.