ADF SR22s and the ANO

[Fuji Abound]

I am thinking about an SR22. I know some have been retrofitted with ADFs and appreciate to operate in IMC this is a legal requirement (although I gather many havent had the retro fit).

I gather there is a proposal to exempt certain aircraft which in itself would avoid the need to amend the ANO. I also gather if you file "ADF non operational" the flight remains "legal". (albeit if in fact you have no ADF, presumably even the filing would be strctly incorrect.)

Any comments please?

[jabberwok]

Under Section 1a of Schedule 5 (when flying under Instrument Flight Rules within controlled airspace) it adds this interesting footnote:

*Unless the appropriate air traffic control unit otherwise permits in relation to the particular flight and provided that the aircraft
complies with any instructions which the air traffic control unit may give in the particular case.

So if you ask your ATC unit to fly IFR (not IMC) in their airspace without an ADF it is in their power to say yes or no. Anyone tried this?

[IO540]

I have no doubt that it is not illegal to continue (with ATC permission, etc) a flight in a plane whose equipment list doesn't meet the equipment carriage regs. To do otherwise would mean that if you are IFR in Class A and your ADF packs up, you would have to land in a field immediately.

But I would be concerned about departing in such a case. The flight (if evidenced by an IFR flight plan for the appropriate IFR/CAS route) would be illegal to start with.

I don't think anybody has ever got done for this (despite widespread rumours about Cirrus pilots being done, etc) but that's probably because the CAA has bigger fish to fry, and also they would come out of any such trial (doing somebody for not carrying an ADF, which has no actual use in airways at FL150 anyway, and most other countries don't require it in their airspace) looking very silly.

It's the insurance I would be concerned about. Most loss adjusters are probably not savvy enough to know these silly little regs, and rarely go beyond checking the aircraft cert of airworthiness etc, but you never know.

But then I am not a lawyer, and if there is any case law on this subject it is being very carefully hidden :)

[High Wing Drifter]

An ADF may not be used in an airway, but it is easiest and most available means of getting from the airway to the airfield without RNAV or GPS, so I don't think they are without use. The need for an ADF in a typically equiped Cirrus is, as usual, another matter.

Sorry for the thread tangent, but as a GPS dunce I've wondered if units like the GNS430 have phantom VOR style RNAV capability. This would surely serve the same purpose as an NDB but with GPS and VORs confirming each other's accuracy?

[IO540]

An ADF may not be used in an airway, but it is easiest and most available means of getting from the airway to the airfield without RNAV or GPS

Only if the airfield has an NDB on it.

The other problem is that only a STAR and an IAP will give you "official" obstacle clearance from the airway to the runway. Otherwise, you are doing the "DIY descent" thing, which is OK but probably not wise with NDB navigation alone.

Also I don't think there are many STARs that terminate on an NDB; most seem to use a nearby VOR, even if the IAP itself does not use a VOR.

The other thing is that BRNAV is mandatory in Europe above about FL095 so one has to ask what you were doing in the airway (most practical European airways routes will take you above FL095) in the first place if you did not have RNAV capability.

I have found an ADF useful as a backup for GPS, on long VFR flights, in certain places (France comes to mind) where there is no VOR in range if routing OCAS. It's much more useful as a locator in approaches.

But one doesn't have to do much IFR (airways) flying to realise that without RNAV it is very very difficult to manage in today's airspace. The whole process is geared up on you being able to fly A - B - C - D where all these are virtual points in space. Ground based navaids are just about irrelevant now. The other day I lost BRNAV capability and was limited to VOR/DME nav. A huge spanner is dropped into the navigation process.... for all the navaid work one does in an IR it is rarely used.

But this is talking about practical things. Fuji's original Q was about the legality.

[Fuji Abound]

Jabberwok - thanks, exactly my understanding and apparently those of others. To take it one step further, the point put to me was that if a flight plan has been filed, then unless rejected by any of the relevant units then the flight has been accepted as without ADF and is legal and permitted. I still worry if this interpretation is too wide but it would see to follow from the section you quote.

I am lead to believe that discussions may already have taken place with the CAA about exempting aircraft with specific avionics fit - is anyway able to comment.

[Engine overtemp]

Air Navigation Order Schedule 5 states you must have...

Scale F
Radio communication and radio navigation equipment capable of enabling the aircraft to be navigated along the intended route including—


(a) automatic direction finding equipment;

(b) distance measuring equipment; and

(c) VHF omni-range equipment.

Seems fairly unambiguous to me. No exemptions are mentioned.

[IO540]

It seems to hinge on whether

Unless the appropriate air traffic control unit otherwise permits in relation to the particular flight

is satisfied by the filing of a flight plan.

I suppose ATC can refuse a flight plan on the basis of the equipment specified, but in reality they rarely if ever look at the FP equipment list.

[avidflyer]

Just looking at the phrase "distance measuring equipment", whereabouts does it say that this has to be a DME box? After all GPS is the ultimate distance measuring euipment, and is probably (guessing,at least)an order of magnitude more accurate than a ground-based DME? (I'm not intending to pursue this line of argument with the CAA, you understand, just playing wth the wording).

[IO540]

That interpretation of "DME" has been thought of before by greater brains than myself but I don't know if any European authority has ruled on it.

The FAA has rules that permit an explicit substitution of a DME (and other things) with an IFR GPS, and my guess is that since they felt the need to formalise such a substitution then others would have to also (or not, as the case is universally in Europe).

Switzerland allows an IFR GPS to substitute for an ADF but that's the only case I am aware of

http://www.ead.eurocontrol.int/eadbasic/pamslight-688D3AE73ADBEB023B7840DB39629BD8/Q5XSVMSJXVSRU/EN/AIP/GEN/LS_GEN_1_5_en_2005-05-12.pdf

[drauk]

Sorry for the thread tangent, but as a GPS dunce I've wondered if units like the GNS430 have phantom VOR style RNAV capability. This would surely serve the same purpose as an NDB but with GPS and VORs confirming each other's accuracy?

Yes, they do. It's pretty counter-intuitive but it's not hard and of course, it is very accurate.

[bookworm]

Sorry for the thread tangent, but as a GPS dunce I've wondered if units like the GNS430 have phantom VOR style RNAV capability. This would surely serve the same purpose as an NDB but with GPS and VORs confirming each other's accuracy?

You mean like a KNS80/81? No, you need DME for that since you need bearing and distance to do VOR-shifting. THe GNS430 has no DME.

Of course the first ever Skyforce box did RNAV by VOR triangulation, so if you ever were to see a similar feature in a modern box, it would be in a Bendix-King one. But why bother?

[drauk]

You mean like a KNS80/81? No, you need DME for that since you need bearing and distance to do VOR-shifting. THe GNS430 has no DME.

I don't know if the original question meant doing VOR-shifting in the sense that an RNAV box does it using an actual VOR and DME or whether they meant achieving the same thing using the GPS. If the former then the above is right: no you can't. If the latter, then as I've said, you can do it using the GNS430. You can use a radial and a distance from a VOR to define a point, which is effectively what a KNS80 does.

[bookworm]

I agree. But in your "define with bearing and distance" scenario you're hardly in a situation where "GPS and VORs confirming each other's accuracy", which is why I interpreted the question as I did. Clarify the question please, HWD.

[drauk]

in your "define with bearing and distance" scenario you're hardly in a situation where "GPS and VORs confirming each other's accuracy"

Yes, I hadn't thought of that.

[High Wing Drifter]

Bookworm,

Well, my question was answered, they don't. I was specifically musing on the benefits/practicality of a unit that combines positions of both RNAV methods as the data is already available (assuming DME input) and it isn't rocket science to write some software to do divergence and tolerance checks just the way airliners do just without the IRS bit (pos by DME/DME, VOR/DME or GNSS). I would have thought such a thing would be very resilient and so as RNAV is requirement for most airways and if you have that level of resilience, then there is very little practical need to impose the carriage of an ADF unless your destination requires it...which not many do having DME and VORs within range. I suppose the need for the odd NDB approach is another thing until we get GNSS non-precision approaches approved. Surely would be a good thing to have anyway.

Just rambling and somewhat incoherent thoughts, my apologies :\