ADF and European navigation (merged)

As my examiner once said: “Any GPS software on a cheap tablet would be 10 times more precise than an ADF. If in an emergency, use your iPad over any ADF”. Must say I agree with him. Only reason I’d have one is because it’s was still a requirement legally, otherwise not.

Thanks all. I take the point about the value of DME and a used KN6X is not going to break the bank. I also see (thanks Peter) how, in the real world, you wouldn’t use the ADF if you had GPS. But, how does one pass an IR or IR(R) revalidation without an ADF if all the local IAPs have the NDB on the plate?

I can see this idea working with a radar service…
RobertL18C wrote:

there is nothing stopping you requesting ATC for different missed approach instructions which do not require an ADF

Hi Raiz, for Cambridge you might request the DME Arc ILS procedure, or the GNSS RNAV procedures, if ATC radar is INOP. Cranfield has GNSS RNAV procedures, and for these the NDB is only required if you plan to use the published missed procedure. Again why the UK requires ground based aids for published missed approaches on a GNSS RNAV is beyond me – no safety case at all, in fact anti safety.

Next time am there will ask for alternative missed instructions and see what ATC come up with.

But, how does one pass an IR or IR(R) revalidation without an ADF if all the local IAPs have the NDB on the plate?

I don’t think you can.

I recall this coming up some months ago. In the past, you (the IR test candidate) had no control over where the FE would send you for the approach(es). You would be told (well, I was) early in the morning of the test day and you had to plan it. Obviously the test aircraft had to have all the gear, to comply with UK CAA Standards Doc 7A or whatever it was called.

Then that changed and it became possible to negotiate with the FE as to which approaches to fly. So if e.g. you had an SR22 with no DME and no ADF, you could pick some approach which didn’t need these.

I don’t know the current situation but it seems obvious to me that with there being no GPS substitution concession in Europe, there cannot be a way to avoid the issue other than to find the right sort of approach.

For the IMCR (IR(R)) the examiner can be anybody qualifed – even the instructor you had for the whole course, so you can work something out…

There may be additional issues using a homebuilt for the test. In the past this was impossible, and even owner maintenance on a certified type was not allowed, but a lot of stuff has changed recently.

Peter wrote:

There may be additional issues using a homebuilt for the test

An owner of an LAA permit can these days be given flight instruction in their aircraft (and pay the instructor), I’d have to imagine the same is true of a checkride.

Raiz wrote:

So, what would you do? Install GPS only, on the basis that EASA will allow WAAS only approaches soon? Install ADF and/or DME? Something else more cunning?

In a homebult; if you got the space for it, and have one at hand, why not? It won’t hurt any bit to have an additional piece of equipment. The only reason not to, would be if you are going to make a super sleek and modern panel, and the ADF would ruin the looks.

But it needs to be effective, for cost and for weight and for panel space. All of these resources have their limits.

Myself would, for what I know now (mainly thanks to this forum) perhaps install DME so as to have some alternative if and when gps suddenly becomes unavailable; unlikely though that seems. ADF is really a thing of the past today, except perhaps in certain areas (Russia comes to mind).

Talking of that, did I understand the Russians had at one time a kind of standard (more or less) precision approach, basing upon two NDB’s, located a bit like an ILS’s outer and middle markers?

I don’t know homebuilt avionics but on the certified glass stuff there is usually a remote reading ADF option, so with a KR87 (arguably the only GA market ADF that works) there is nothing at all in the panel. You just get an ADF pointer as a part of the RMI presentation e.g. as shown here (after halfway).

Peter wrote:

You can set an IFR GPS to 1nm or 0.3nm full-scale manually.

True, but the full scale indication of the CDI is not the issue. It is the integrity value. If the integrity remains at enroute, then depending on the GPS, it will be +/- 2 or +/- 5 NM NM before an alert will be generated indicating to the pilot that the CDI is misleading (aka RAIM failure). With an approach mode, the integrity value will be 0.3 NM for a NPA.

Hardly a solution for genuine IFR kit, but AvMap can display Airfields/NDB/VOR on their modestly priced Ultra EFIS, though purely from GPS data (supplied by Jepp):