I am optimistic that somebody has already been tru all the AIP's and could tell me which countries require the ADF carriage.
Funny that; I started on this (a matrix of equipment versus country versus airspace class versus flight rules) a few years ago and, suprise suprise, never got very far with it
It also changes frequently. It would be an impossible task to do accurately.
Also not all AIPs are online. Eurocontrol has a list of AIP sites
here and there is more on their horrid
EAD site. But some (Greece and I think Italy) are printed only and you have to buy them.
For the most part, nobody cares much about your equipment otherwise aviation would grind to a halt. Loads of Cirruses are illegal for IFR in Europe, due to not having a DME which is a virtually universal IFR requirement in Europe and is not likely to go away. There are probably airliners landing all over Europe right now which are not carrying a 406MHz ELT, etc, but I think all will have an ADF.
Some equipment is obvious by absence e.g. Mode C or Mode S, and I reckon that some provocative items (like a 406MHz ELT) will be ramp checked around Europe in the coming years (especially France if you are N-reg
).
The ADF is suprisingly common in the 3rd world; e.g. Russia has NDB approaches which have two NDBs and you have two ADFs and fly to keep the two needles pointing at "you".
The regs (private flying) do not specify equipment to be USED; only one to be CARRIED. This means that flying an NDB approach using the GPS (as done by every smart pilot) is 100% legal. But you do need to carry the ADF to be legal (there is an argument around that one too; for UK Class G, and therre is another one that GPS meets the verbal definition of a DME, and it would not suprise me if the CAA had got a legal view on this years ago and sensibly decided to not test it..................).
Had a CAA Flt Ops pilot observing on a trip a year or two ago into Bom in a B744F. We flew the vor/dme procedure with the a/p coupled to the FMS as Co. SOPS in Vnav/Lnav.(triple GPS input into FMS and VOR displayed on non handling pilots PFD map)
After landing debrief included the comment that we should have flown the AP in Heading and V/S as we were not cleared for GPS approaches!.
What bollox
I am told no modern airline flies NDB approaches using the ADF. They fly them on the FMS, and are supposed to check the ADF at certain points (e.g. the FAF) as defined in the company OPS manual.