How do you fly an RNAV approach?

[kityatyi]

Which autopilot modes do you engage for an RNAV approach in the Fokker? Is the aircraft capable of following the glide path during the RNAV approach?

[JabbyJabara]

They technically can based on the FMS and the IRS system but without a GPS you would illegally be conducting them without equipment giving accuracy to .3 of a nautical mile.

You can set the AP into Nav and PROF and it'll follow the rough profile on the FMS

[MartijnCoenen]

Correct, the Fokkers do not have GNSS/GPS so can't fly an RNAV. Same in real life.
You can fly them in the sim, but the systems are not build or certified for it.