FAA's Advisory Circular No. 90-108. March 3rd, 2011
That AIC is only half the picture - it actually prohibits GPS substitution for the final approach aid, so you could not fly an NDB approach based on this.
But over ten years ago, the FAA separately had an approach overlay program where ADF approaches became "ADF RNAV or GPS" approaches, which allowed use of GPS instead of the main Nav-aid. Since the approaches used the tracks and minima of the legacy approach aid, no procedure design was necessary, if effectively was a chart renaming exercise. These are being phased out and replaced with proper GPS approaches, so the minima are lower and the navigation to the FAF is standardised around the "Standard T".
So in effect, in the US allowes total substitution for ADF.
Cobalt, I was talking about the SR22 where you have the ILS approach chart LIVE on the MFD. You can actually see when you reach the FAF and that's good enough for the altitude check, at least it works perfectly in my plane. I also have the sequencing of the approach on the 430 with the precise distances to each waypoint. I would NOT do that without a live approach chart on the MFD, but in the Cirrus this works fine.
Neil: obviously for you te only rhigt place i n the world is somewbere in USA. It'z a point of view. But Europe is qhite central for a huge worldwide Population.
And no, ADF is not usful in western and central europe, because NDB are shut down. In our country, there are only 3 (!) in sdrvice. Aproaches have bee co.pleted by GPS non precision procedures with groundbased correcfion signal (EGNOS..) for details, see The IFR aproach charts, for example LSGS.
NDB is alive and well out here in Asia, mainly for use picking up the ATIS at the regional airports. :-)
I had one fitted in the US to the Jetprop just for that purpose. The avionics shop in Vero Beach thought I was nuts and struggled to locate a new one.
E
You should still be able to buy a new KR87.
This has been the only GA ADF that actually works for longer than 5 minutes and carries on working after it has been raining overnight 
I have one in the TB20. It was a factory fit from 2002; the plane would have been illegal for IFR otherwise. I later bought the components of another one from a US pilot so I have that on the shelf as a spare.
Just don't try flying approaches with it, especially at any coastal airport 
I had some hilarious situations at the Diamond and Cirrus stands at some exhibition in 2002 when I asked for an ADF and explained that it is a legal requirement for IFR in CAS in the UK and some of Europe. Diamond had no room for it, and the Cirrus dealer said GPS is much better and walked off to speak to another customer, thus losing about €250k. I can't remember the name of the company but it was probably the well known one...
It will be fun (NOT) if some German CAA official decides to enforce equipment carriage and grounds a few thousand expensive planes...
This has been the only GA ADF that actually works for longer than 5 minutes and carries on working after it has been raining overnight
So far my KR85 has been reliable too (as far as ADF's can go...)
-You should still be able to buy a new KR87.
Yes, that is what I ended up with. At the time circa 2008, Honeywell closed a production facility down in Singapore, or so I was led to believe and supply of new ones were limited. We did find a new one eventually. ATIS sounds as crackly on it now as when it was new, :-)
E
At the time circa 2008, Honeywell closed a production facility down in Singapore
That is really interesting, because I have seen various PCBs like this with "Singapore" on them. I could not understand what totally bizzare economics would make it worth making low value stuff like this (a $20 PCB in a $3k servo) all the way out there.
Does anybody know if an ADF is still required for IFR in Europe from a N-reg? I know a DME is but I’m not sure concerning an ADF.
Muelli,
“Europe” currently doesn’t exist in terms of airspace regulation – single countries regulate their airspaces and equipment requirements.
See FSAV and you see that Germany does not strictly mandate an ADF.
You would have to check all the various countries’ equivalents to the FSAV. GEN 1.5 is usually a good place to start but then you normally have to check various cross-referenced documents like AICs, etc.
I’m sure you don’t want to do that, do you?
