Use of RNAV Equipment on Conventional procedures

[Breakthesilence]

I was discussing the subject with colleagues and everyone has a different opinion. The issue is: Can you fly a Conventional procedures (i.e. SIDs, STARs etc.) with the RNAV equipment (FMC, GPS ecc.) if a Navaid is unserviceable?

I'm referring to non-overlay procedures, just plain conventional ones.

It happened to me that, given a Navaid Inoperative, some airports are using alternate departures (based on other navaids) while others are still giving the procedure in your clearance.

What does EASA say about this? As far as I understood, the FAA is allowing using RNAV anyway.

I can't find a clear answer on my company manuals.

[Too Few Stripes]

PANS-OPS
1.4 USE OF FLIGHT MANAGEMENT SYSTEM (FMS)/ AREA NAVIGATION (RNAV) EQUIPMENT

1.4.1 Where FMS/RNAV equipment is available, it may be used to fly conventional procedures provided:

a) the procedure is monitored using the basic display normally associated with that procedure; and

b) the tolerances for flight using raw data on the basic display are complied with.

[FlightDetent]

Sounds logical. How could it be possible any other way?

Oh, wait...

Already 10 years ago a leading aircraft manufacturer inserted a paragraph saying effectively otherwise ('as long as relevant local regulatory conditions are complied with') into their OEM FCOM.

Which pretty means it is possible somehow/somewhere and the research has been done.

Not so crazy after you realize the overlay flys a more accurate track than the signal shows.

On an RNP (approach) capable equipment, map shifts without alerts about the downgrade of accuracy only happen in the SIM and it is vain negative training.

Clear as mud?

[Breakthesilence]

Too Few Stripes

Thanks for the reference, so it means that the Navaid is required to be operative. So how comes the ATC provides SIDs with an inoperative VOR without a backup (no NDB co-located, no overlay RNAV procedure)?