Peter wrote:
Was any LORAN box ever certified for this?
Yes. LORAN was/is an option for the Honeywell GNS-XL FMS (and similar units) installed in anything from single engine turbine upwards.
what_next wrote:
For higher levels of RNAV (PRNAV or RNP1 or whatever) a certified and current database is a requirement and and self-entry of coordinates by the end user is verboten.
Using an expired database is not the same as manually entering the waypoint lat/long…. AFAIK it is acceptable (certainly it is in the USA) to use an expired database for enroute navigation, provided the pilot has verified that the particular waypoints being used (in the expired database) have not changed…presumably this can be done by referring to a current chart. I think you can also fly a GPS approach with an expired database provided you verify that the IAP has not been updated since the database expired….of course in Europe I imagine that would be way too pragmatic…but I don’t know.
Peter wrote:
It depends on the AFMS. See the details here
You are quite right. I checked the AFMS for the GNS430W with SW 5.10 that I had in the Mooney and expired database can be used for Enroute, Oceanic and Terminal IFR navigation subject to verification….But NOT for RNAV (GPS) approaches…
(It may be obscure, but I’m sure there it is useful information for others nonetheless and probably not worth a new thread)…
From here
A_and_C wrote:
ADF is still a legal requirement in some places
Not in EASA-land. Of course if you need to use NDBs then you have to have an ADF. GPS fix substitution is not allowed. (Yet, there is a proposal to change that.)
I couldn’t agree more and in the UK probably the second most available approach after the ILS.
It’s also useable at low levels whereas VOR’S aren’t.
I would fit one.
Bathman wrote:
I couldn’t agree more and in the UK probably the second most available approach after the ILS.It’s also useable at low levels whereas VOR’S aren’t.
I would fit one [ADF].
Just for fun, I checked all Swedish instrument airports (46). Only one single airport had a runway where only an NDB approach was available. This actually surprised me, but we’ve got lots of new RNP approaches this year. So for practical purposes having an ADF in Sweden is pointless. It is still legally required for some ILS procedures, but when the proposed change to part-NCO allowing GPS fix substitution is approved, then it will also be pointless from a legal point of view.
A quick look at the eight airfields I have visited in the last two weeks paints a picture of why I decided to fit an ADF
Membury and Enstone have no instrumental procedure.
Goose Bay and Bromont ( Quebec ) have instrumental procedures but no NDB
Wick, Reykjavík, Narssarssuaq and Oxford have instrument procedures and NDB based approaches.
when the proposed change to part-NCO allowing GPS fix substitution is approved,
This has been “in discussion” for at least 20 years 
Indeed, the UK still has a very few airfields where an NDB approach could theoretically be helpful, i.e. where there are no ILS/LOC/VOR approaches at the same time.
Of those which are realistic GA destinations:
Then there are few airfields which have both NDB and RNAV approaches. The low end of GA being operated pretty much on a shoestring in the UK, many “IFR” aircraft have not yet been fitted with approach-approved GPSes (not even LNAV only), so NDB is the only alternative. Alderney comes to mind (though not technically "UK).
Practically speaking, one could of course rather fly a DIY-approach using GPS, rather then NDB, especially at those coastal airfields.
