ADF/DME Carriage Requirements AGAIN

[denhamflyer]

What is the ACTUAL law regarding carriage of equipment in controlled airspace. I thought I knew this but having read some comments recently I looked it up again. To find some conflicting information. Now before we get lots of should and stupid if you dont... I would like to clarify the actual law.

The AIP (http://www.ais.org.uk/aes/pubs/aip/pdf/gen/10105.PDF) seems to be clear - GEN 1.5.3 says VOR+DME+ADF plus some wording allowing ATC to provide special exemptions per flight. This is what I understood.

BUT reading the ANO (http://www.opsi.gov.uk/si/si2005/20051970.htm#19) we get what seems to be the same except:-

Article 20(2) SCHEDULE 5 paragraph 5(e) when flying under Instrument Flight Rules within controlled airspace and not required to comply with paragraph (5)(a) above ( 5 (a) is IFR for PUBLIC TRANSPORT). Then ONLY scale A = Two Way Radio is required.

This appears to mean non-public transport flights for UK registered aircraft dont need ADF/DME?? Am I reading this correctly or am I having a bad day...

Now I have always been told the ANO is the LAW vs AIP so can some legal beagles clarify this?

[Islander2]

You're looking at the wrong paragraph of ANO Schedule 5.

Para 1 (a) stipulates SSR, ADF, DME & VOR for all aircraft flying under IFR in U.K. controlled airspace (subject, as you noted, to certain specified exemptions).

[denhamflyer]

Im not sure I agree - if so then paragraph 5 would not need to exist in its current form. To me I read this as more specific than 1 and that it specifically refers to UK Registered aircraft ( 5 All aircraft registered in the United Kingdom, wherever they may be—) i.e. it should read outside the United Kingdom if the UK airspace was not to be included.

I stand to be corrected.

[Contacttower]

Had you read this at the bottom of page 2 of the AIP document you linked?

1.2.6.1 State aircraft are exempt from the requirement for carriage of RNAV equipment. No other general exemption from these
requirements will be granted, but, in very special circumstances, relaxation of the requirements, for a single flight, may be approved by
the appropriate ATC Unit (see paragraph 1.3.3 for exemptions from the carriage of SSR for limited periods).

My understanding of the law would be that you can fly IFR in CAS in the UK on G-reg without ADF/VOR/DME as long as it's not Public transport.

[Islander2]

i.e. it should read outside the United Kingdom if the UK airspace was not to be included.Equally, paragraph 1 should read 'excluding aircraft registered in the United Kingdom' if they weren't to be included!

I agree it's ambiguous.

[denhamflyer]

Thanks Contacttower I had read the paragraph but for some stupid reason I read RNAV=Airways RNAV=GNSS. So missed the bleeding obvious.:O

Interesting that there is an assumption by many that VOR/DME/ADF was a requirement. But they must be flying N-Reg :p

[High Wing Drifter]

Schedule 5, para 1a says to me that you need ADF, VOR and DME when IFR in CAS for any flight unless specifically exempt.

[Islander2]

Thanks Contacttower I had read the paragraph but for some stupid reason I read RNAV=Airways RNAV=GNSS. So missed the bleeding obvious.:ONot so fast!

That paragraph in AIP Gen 1.5.3 is irrelevant ... it doesn't apply. 'State aircraft' is not an alternative term for 'UK-registered aircraft'. Both the ANO and the AIP use the term 'UK-registered' when that's what they mean. The ANO defines 'State aircraft' as aircraft engaged in military, customs, police or similar services. Furthermore, RNAV is NOT used in the AIP (including within 1.5.3) as alternative terminology for individual ADF, DME, VOR sets.

Everything that I've seen the CAA write on this subject, especially at the time that FM Immunity became a requirement, suggests they believe (in the absence of a court ruling) that section 2 paragraph 1 of Schedule 5 applies equally to G-reg aeroplanes.

The other thing to note is that Schedule 5 specifically contemplates that an aircraft could be flying in a combination of the prescribed circumstances ... in other words it is NOT a question of choosing between 1(a) and 5(e), they both apply and both sets of requirements must be met (although the preamble to Schedule 5 notes that the scales of equipment don't need to be duplicated in those circumstances - which in this case I would interpret as you not needing 2 lots of scale A).

[Contacttower]

That paragraph in AIP Gen 1.5.3 is irrelevant ... it doesn't apply. 'State aircraft' is not an alternative term for 'UK-registered aircraft'. Both the ANO and the AIP use the term 'UK-registered' when that's what they mean. The ANO defines 'State aircraft' as aircraft engaged in military, customs, police or similar services. Furthermore, RNAV is NOT used in the AIP (including within 1.5.3) as alternative terminology for individual ADF, DME, VOR sets.



You've got me there, but...

(1) All aircraft (other than gliders) within the United Kingdom—

(a) when flying under Instrument Flight Rules within controlled airspace

next to (a) it lists VOR/DME/ADF as requirements

But further down the page it says:

(5) All aircraft registered in the United Kingdom, wherever they may be—

(e) when flying under Instrument Flight Rules within controlled airspace and not required to comply with paragraph (5)(a) above

(5)(a) refers to public transport and next to (e) it quite clearly indicates simply a two way radio.


One intepretation (although a rather stupid one) is that G-reg aircraft can operate IFR in CAS, as long as not in the UK.

[High Wing Drifter]

What it is saying is that all aircraft in the UK regardless of state of registration are subject to Schedule 5 para 1(a) (ADF, VOR, DME) are required.

All UK registered aircraft that are not public transport flying IFR in CAS in another state (other than the UK) are subject to that state's requirements, but the ANO says that they must have at least equipment scale A (a radio).

[Islander2]

One intepretation (although a rather stupid one) is that G-reg aircraft can operate IFR in CAS, as long as not in the UK.Well (assuming you mean without ADF/DME/VOR) that's one interpretation ... and IMHO it's the correct one - subject to any more onerous laws of the state in question. The only alternative interpretation (possibly even more stupid) is that overseas-registered aircraft are subject to a more onerous equipment regime in UK airspace than are UK-registered aircraft.

Taken individually, it's absolutely clear that 1(a) and 5(e), as drafted, are mutually exclusive for non-PT, G-reg operation under IFR in CAS in UK airspace. If a choice is necessary, only a court could determine which should prevail!

But, as I pointed out in my previous post, they don't have to be taken individually and a choice isn't necessary. Indeed, the preamble to Schedule 5 specifically contemplates that they may BOTH apply!

Oh, and HWD:
What it is saying is that ... all UK registered aircraft that are not public transport flying IFR in CAS in another state (other than the UK) are subject to that state's requirements, but the ANO says that they must have at least equipment scale A (a radio).That is NOT what it says, that's your interpretation! 'Wherever they may be' clearly includes the UK and so it does not say (although maybe it was meant to!) 'other than the UK'.

[Contacttower]

Well (assuming you mean without ADF/DME/VOR) that's one interpretation ... and IMHO it's the correct one - subject to any more onerous laws of the state in question.


That is what I meant.


That is NOT what it says, that's your interpretation! 'Wherever they may be' clearly includes the UK and so it does not say (although maybe it was meant to!) 'other than the UK'.


Well quite, HWD's post sounds very sensible and probably is the 'answer' but what it actually says appears to contradict itself.

[High Wing Drifter]

My interpretation (as cheerfully coined by Islander) identifies the most restrictive (or limiting if you prefer) case. So if you are in CAS and IFR in the UK, then regardless of your state of registration you fall under Sched 5 1a. If you are UK registered not PT in CAS under IFR then you fall under Sched 5e regardless of what country you are in. If you happen to be in the UK, then you have to add Shed 1a to Shed 5e to find your requirement. It just so happens that in this case they both duplicate the scale A requirement. I don't see where they contradict each other.

[DFC]

The AIP GEN 1.5 is the reference and is clear and easy to understand.

Why do you bother with the ANO?

Are you going to spend the same amount of time reading the Legal regulations published by the French Government before you fly there?......good luck if you are.

Does everyone who trawls through the ANO looking for answers that are published for them in the AIP put down the highway code booklet so that they can read several road traffic acts and various related instrments and bye laws?

The AIP is given legal status by the AViation Acts and the ANO because everything in it is "notified".

If you follow the AIP, you will never fall foul of the law.

Finally, yes, ADF is required for IFR flight in the UK's controlled airspace below FL245. The very good reason for that is that there is still enroute navigation that uses NDB to define position and many airfields use it as part of the initial/intermediate/final/missed approach procedure

Regards,

DFC

[Contacttower]

The only alternative interpretation (possibly even more stupid) is that overseas-registered aircraft are subject to a more onerous equipment regime in UK airspace than are UK-registered aircraft.



Having read it again I'm starting to think that maybe this the answer...surely though this has been answered before? Although I couldn't find anything on the search. (Why can't they scrap the four word seach minimum?...Its such a pain in such a acronym dominated activity. :E)

[n5296s]

Finally, yes, ADF is required for IFR flight in the UK's controlled airspace below FL245. The very good reason for that is that there is still enroute navigation that uses NDB to define position and many airfields use it as part of the initial/intermediate/final/missed approach procedure

That doesn't seem a "very good reason" at all. GPS can do a perfectly fine job of navigating with respect to the position of an NDB. (Of course it can also do a perfectly fine job of telling you how far you are from a VOR).

I'm puzzled as to whether this requirement (and specifically the non-allowance of GPS as an alternative) stems from (a) inertia of the "what was good enough for my grandfather better be good enough for you" variety or (b) a sort of anti-US-imperialism sentiment because GPS is run by the US: "can't trust those wretched yankees, bunch of cads".

Of course in the US GPS is permitted as an alternative to both ADF and DME. Which, to anyone who has ever tried to fly an approach solely by ADF, will be recognised as a Good Thing.

n5296s

[IO540]

A quick look at some other AIPs at the Eurocontrol (http://www.ead.eurocontrol.int/) EAD website suggests an ADF requirement is not common although Sweden requires not just an ADF (http://www.ead.eurocontrol.int/eadbasic/pamslight-BC2EBB7A6DEBBE9E7D2FF61E7BBC2ACF/YSVV75F2KXZHI/EN/AIP/ENR/ES_ENR_1_3_en_2007-04-12.pdf) but also, like the USA, an ELT (http://www.ead.eurocontrol.int/eadbasic/pamslight-BC2EBB7A6DEBBE9E7D2FF61E7BBC2ACF/YSVV75F2KXZHI/EN/AIP/GEN/ES_GEN_1_5_en_2007-08-30.pdf) transmitting on 121.5 and the soon to be defunct 243MHz.

The equipment list for each country is in the country's AIP GEN 1.5 and for Switzerland (http://www.ead.eurocontrol.int/eadbasic/pamslight-BC2EBB7A6DEBBE9E7D2FF61E7BBC2ACF/Q5XSVMSJXVSRU/EN/AIP/GEN/LS_GEN_1_5_en_2007-04-12.pdf) it returns the interesting result that a BRNAV GPS removes the need for an ADF for all IFR flight (ADF is still explicitly required for approaches containing NDBs, as one might expect).

Germany (http://www.ead.eurocontrol.int/eadbasic/pamslight-BC2EBB7A6DEBBE9E7D2FF61E7BBC2ACF/OODUMTUY4LXFU/EN/AIP/GEN/ED_GEN_1_5_en_2007-01-18.pdf) requires an ADF only for approaches which use an NDB, which makes sense.

France (http://www.ead.eurocontrol.int/eadbasic/pamslight-BC2EBB7A6DEBBE9E7D2FF61E7BBC2ACF/SVR2UEKJIUOIC/EN/AIP/GEN/LF_GEN_1_5_en_2007-05-10.pdf) does not require an ADF.

The trend for most of the "up and coming" European countries such as the Czech Rep (http://www.ead.eurocontrol.int/eadbasic/pamslight-BC2EBB7A6DEBBE9E7D2FF61E7BBC2ACF/TX5YQMUS5OUVO/EN/AIP/GEN/LK_GEN_1_5_en_2007-03-15.pdf) is to not require an ADF.

So, the UK is the odd one out, with a gold plated requirement for ADF enroute.

Most countries do however require a DME and - unlike in the USA, and with the Swiss exception - a GPS cannot be used instead

I don't but ANY justification for an ADF other than to fly approaches that use an NDB, but unfortunately that reason is strong enough to have it fitted to make the plane at all useful for IFR.

(edit: apologies for broken links - the Eurocontrol website changes URLs every few days)

[bookworm]

Well (assuming you mean without ADF/DME/VOR) that's one interpretation ...

I'm surprised you find any ambiguity in this. For example, aircraft required to comply with Art 54 aren't automatically exempted from Art 52. Why in Scehdule 5 should an aircraft required to comply with sub-paragraph 5 be exempted from sub-paragraph 1?

Any aircraft (other than gliders) flying IFR in controlled airspace in the UK requires scales A, E1 and F

Any aircraft (other than gliders) registered in the UK requires flying for PT under IFR requires scale A, C, E1 and H

Any aircraft (other than gliders) registered in the UK requires flying under IFR requires scale A.

Therefore:

a UK registered aircraft under IFR in controlled airspace in the UK flying for PT requires scales A, C, E1, F and H. But it is not required to duplicate equipment merely because F and H both appear, hence since F is a subset of H, this is equivalent to A, C, E1 and H.

a UK registered aircraft IFR in controlled airspace in the UK not flying for PT requires scales A, E1, and F.

[scooter boy]

"this requirement (and specifically the non-allowance of GPS as an alternative) stems from (a) inertia of the "what was good enough for my grandfather better be good enough for you" variety or (b) a sort of anti-US-imperialism sentiment because GPS is run by the US: "can't trust those wretched yankees, bunch of cads."



Even with ADF/DME fitted, I know I trust the GPS more!

Sad though that new N-reg imports require this very expensive (£10000+)outdated box to clutter up the panel and add extra weight.

Hopefully our regs will change and we will move forwards in line with the more progressive aviating states in the world.

Here's hoping,

SB

[DFC]

In the UK for the time being, VOR, DME and ADF are the basic navigation aids that every IFR flight in controlled airspace will have.

The extra requirement to have BRNAV equipment only applies above FL95 or on certain routes.

A fully approved panel monuted GPS that meets BRNAV requirements (PRNAV in some cases plus approach procedures etc) and which always has a fully up to date database is at the moment considered to be extra equipment which is not necessary to fly at the lower levels IFR.

Regards,

DFC

[Contacttower]

Hopefully our regs will change and we will move forwards in line with the more progressive aviating states in the world.



ADF is going out next year, at least that was what I was told by my IMC rating examiner.

[scooter boy]

Great news Contact Tower.
Let us hope that he is right and that it comes to pass!
SB

[IO540]

I think we can get bogged down in the "ADF enroute" argument without realising the "ADF in approaches" thing is not going to go away anyway.

I can see UK's peculiar ADF enroute requirement going away (it's hardly echoed elsewhere in JAA/EASA-land already) but I can't see the general requirement for an ADF to fly approaches in UK and Europe going away.

How can it??

There would have to be a general de-commissioning of NDBs in approaches, and what they be replaced with? Almost nobody is going to replace an NDB with a VOR because a VOR costs much more to install and run. GPS is the only option, and that will happen when it happens.........

So, the discussion of doing away with the ADF totally hinges on a wholesale adoption of GPS approaches at every airport that currently has an instrument approach involving an NDB. This is going to take many years, at best.

Unless one adopts the U.S. style which is to allow an IFR GPS to be used instead of ADF and DME, and I see no indication whatsoever of this being adopted anytime soon either.

(And, don't forget, not carrying an NDB/DME in the USA does limit your legal options when it comes to alternates.)

So, while I think mandatory ADF-enroute is totally stupid, I really cannot see the slightest chance of the ADF going away for approaches in Europe for many years - IF you want half decent IFR utility from your plane.

On top of this, Cirrus owners usually want to avoid the DME too. This is much less likely to go away than the ADF. DME isn't "mandatory" on all that many approaches in Europe but the alternatives are often not available. Radar is one alternative but IME is so often temporarily unavailable at the smaller destinations; all you need is an ATCO (who is qualified and paid extra to provide a radar service) to be off sick... Timing is another alternative but frankly, in some places that have serious terrain around, I would rather know exactly where I am.

When I used to fly long legs VFR over say France I used to use the ADF as an enroute backup for the GPS. This is just handy and I would not suggest it is essential, but it does illustrate that the ADF is not useless.

[Contacttower]

I don't know the detail of it IO540....it was something the examiner mentioned in passing during the test. At the time I was more contentrating on the ADF itself to ask further questions. I quite like them in those situations when you just want something to point at your destinations, but for approaches they are just :yuk:.

[n5296s]

So, while I think mandatory ADF-enroute is totally stupid, I really cannot see the slightest chance of the ADF going away for approaches in Europe for many years - IF you want half decent IFR utility from your plane.

On top of this, Cirrus owners usually want to avoid the DME too. This is much less likely to go away than the ADF. DME isn't "mandatory" on all that many approaches in Europe but the alternatives are often not available.

I don't follow this at all. GPS is an excellent alternative to both ADF and DME, both enroute and for approaches. In the US, all NDB approaches (well, no doubt there's an obscure exception somewhere) are designated so they can legally be flown with an approach-certified GPS *instead* of an ADF. There are a few approaches which require DME and aren't designated to allow GPS as an alternat(iv)e, althugh since DME is never fitted to new aircraft I guess everyone either flies another approach or just uses GPS anyway. GPS is *always* legal where ADF/DME are needed only as part of the missed.

I guess the belief in the UK (by the CAA and by pilots) is that IFR-capable GPS units are rare exotica, that nobody who doesn't regularly fly above FL095 could ever conceivably have. Whereas in fact practically all new planes have them. Even the new Cessna 162 has a glass panel!

I did hang on to the ADF that came with my plane for a while, it had a useful timer and it was always set to point to my home airport, which conveniently has a 50kW AM station close by. But when its power supply went on the blink, I used the panel hole for a backup AI. You'd have to be crazy or desperate to fly an NDB approach just by the ADF in actual (yes, I know airliners routinely do it in places like Albania, but it doesn't change my sentiment).

n5296s

[tmmorris]

You'd have to be crazy or desperate to fly an NDB approach just by the ADF in actual

Absolutely. I don't have an IFR GPS in the ac I fly most often, so I carry a hand-held one. But I still fly NDB approaches on the handheld GPS, backed up by the ADF/DME, and I defy anyone who says that is more dangerous than flying by reference to the ADF and stopwatch alone. (Even the CAA... or DFC...)

Tim

[Contacttower]

I defy anyone who says that is more dangerous than flying by reference to the ADF and stopwatch alone. (Even the CAA... or DFC...)



I would draw the line at NDB/DME approaches...NDB alone is just too hardcore. I noticed the other day when SAM at Southampton was out and the ATIS was stating 'NDB/DME approach' most aircraft were just asking for visual...no suprise really.

[DFC]

tmmorris,

Once again a "I can't do it so everyone else is crazy to even attempt it" puff the chest out statement.

If the NDB and timing says one thing and the VFR only handheld GPS says another while in IMC, what are you going to do other than go-arround?

Thus you are simply cross-checking the primary ADF/timing aid. You are not using an alternative approach aid.

If however, you would continue using the VFR only handheld GPS then why bother to tune the ADF in the first place, you are breaking the law (reckless) from the moment you ignore the GPS manufacturer's warning.

---------

n5296s,

Many aircraft have various pieces of equipment fitted. However being fitted and being certified for IFR use is something different altogether.

GPS replacing DME can cause problems for when dealing with a DME associated with an ILS. the DME station will be lolcated to one side of and about half way along the runway strip. The responses are adjusted so that the indication is 0 in a circle about the station that crosses both thresholds. Now using your GPS do you use the station as the zero point or threshold 1 or threshold 2. The answer of course is that it depends on if you are enroute (makes little difference) or making an approach (need the approach end) or departing (need the departure end).

Thus the "replacing DME" is not 100% accurate.

--------

IO540,

The price of VORs are dropping rapidly. There is the issue of calibration and maintenance but they offer lower minima and better options from an ATC point of view in a procedural environment. The DMEs are not going to go away because many aircraft use DME/DME for RNAV and for that reason many VORs are being turned off while their associated DME will remain.

Regards,

DFC

[Contacttower]

To recap though I think we have established that it is the law that one needs ADF and VOR/DME to operate IFR in CAS.


The price of VORs are dropping rapidly.


Well in that case when Southampton decide to sell SAM, I'll buy it and stick it in my garden... then I could have my own IAP to my own field and :mad: what the CAA thinks.

[tmmorris]

DFC, like many before me I am moved to wonder if you've ever flown an aircraft, and in this particular case whether you've flown an NDB approach in IMC. Least of all at Gloucester or Shoreham.

Are you suggesting, by the way, that the NDB might be so inaccurate that it and the GPS might disagree violently? If so, why on earth are we basing approaches on them?

And I never said I couldn't do an NDB approach based solely on the ADF. Indeed, if you consult the CAA records you will find that I have held an IMC rating since 2003 and have demonstrated my ability to do so therefore to an examiner on three separate occasions. I just said I wouldn't.

Tim

[n5296s]

Once again a "I can't do it so everyone else is crazy to even attempt it" puff the chest out statement.
Huh? I've certainly flown NDB approaches, I even did one on my IFR checkride. Much to my own and the examiner's amazement, I came out with the nose pointing at the runway. Statistically, this is highly improbable. (Think about the lateral error with 1% compass accuracy and 1% pilot error following the 1% compass error - both of which are pretty good going - and the NDB 5 miles off the approach end of the runway). I've even flown them to minimums. I can't any more, because even if I still had my ADF, all the NDB approaches within 100 miles of my home base have been decommissioned.

But all that said, if conditions were down to minimums, unless the terrain was extremely favourable (which I guess it always is in the UK), I'd divert somewhere with a nice friendly ILS rather than fly an NDB approach without GPS.

(item about DME accuracy, which I can't readily quote)
If that is the case (which would imply that the DME antenna must be exactly half-way down the runway, which I suspect is rare in practice) then I guess that nice Mr Jeppsen and Mr Garmin have figured that out and adjusted the readout accordingly, when I am showing simulated DME from a localizer. Most approaches that use DME are actually doing DME off a VOR rather than the localizer - although there are exceptions.

n5296s

[DFC]

If that is the case (which would imply that the DME antenna must be exactly half-way down the runway, which I suspect is rare in practice) then I guess that nice Mr Jeppsen and Mr Garmin have figured that out and adjusted the readout accordingly

No. Think about it for a few seconds. The DME only has to be equidistant from both thresholds. It is very common - ILS at both ends (same frequency but different idents) using a switchover but 1 DME for both ends.

I am aware on a number of commercial operators who are having problems with the Jeppesen database for the ILS DME used for the departure runway. On a SID, the procedure specifies a turn at x distance by reference to the DME. However, the FMS can turn one early (by the length of the runway) because the DME reads 0 at the departure end but the FMS location for 0 DME is the approach end.

It is being monitored and also being worked on by Jeppesen but the final solution has yet to be decided.

------------

tmmorris,

Yes I have been to both places and used the NDB at both places. However, you have missed the important point - if the GPS says something different from the ADF your only option is to not trust both of them because you can not put more faith in a VFR handheld GPS unit than in a certified ADF (even with the errors).

Put another way, if by following the handheld VFR GPS you leave the +/-5 on the ADF, you are legally guilty of reckless endangerment despite the outcome.

I hear all the time on here about ADF problems. I must ask how many MORs have been filed when the ADF was giving dangerous indications. After all if you find an approach aid is dangerously out, you have an obligation to report it.

Most people get their compass swung when required. However, few seem to get their ADF swung and from my experience, most ADFs are inaccurate simply because the ADF has not been serviced properly and has not been swung to check it.

Regards,

DFC

[n5296s]

No. Think about it for a few seconds. The DME only has to be equidistant from both thresholds. It is very common - ILS at both ends (same frequency but different idents) using a switchover but 1 DME for both ends.
Well, of course I didn't mean that the antenna was actually in the middle of the runway, just (to be pedantic) located on a line perpendicular to the centre of the runway.

Now I understand what you're saying about the DME "trick", I don't understand how it actually works. What this means is that the DME would read negative if you're between the threshold and the antenna. Wouldn't that mean it would have to send its response pulse before it received the interrogation?

n5296s

[Fuji Abound]

Huh? I've certainly flown NDB approaches, I even did one on my IFR checkride. Much to my own and the examiner's amazement, I came out with the nose pointing at the runway.

Yep, they work well. It is just they are harder to fly well and so often the kit in the iarcraft does not work properly.

Wait and see, I think you will find type exemptions will be with us very shortly. :).

[CJ Driver]

Now I understand what you're saying about the DME "trick", I don't understand how it actually works. What this means is that the DME would read negative if you're between the threshold and the antenna. Wouldn't that mean it would have to send its response pulse before it received the interrogation?

It works because a "normal" DME reply includes a fixed standard delay to allow for ground station processing. By reducing the delay you can "subtract" some distance, and make the DME appear closer than it really is. By putting the ground station equidistant to the two thresholds and subtracting delay equal to half the length of the runway, the DME reads "zero" at the threshold. And yes, after you have landed you will be into "negative" territory - next time you are at an airport with such an installation, take a look and you will notice that the DME will lose lock when you are closer to the ground station than half the runway length.

[Sir George Cayley]

My man at the CAA tells me it is planned to submit proposals to remove the ADF carriage requirements from the UK ANO in 2008.

There is a mid-year reissue planned, so it could be in that (or not in there for those pedants eager to point out that removal will cause an absence of words):ugh:

Of course, the dreaded public consultation and Regulatory Impact Assessments will no doubt add delay and apparently the work is bound up with other policy changes on airspace etc.

Nevertheless, if you are planning to take delivery of your Cirrus or Cessna 400 Columbia next summer you won't need to worry about getting a hole cutter from B&Q for the ADF dial.

And those of you filing IFR and putting "ADF inop" in the free text box won't have to hold crossed fingers behind your backs:=

Suggest someone keeps a lookout for the web notification and we all vote yes when the time comes.

BTW don't wait for SAM to come on the market. Compton NDB is on Ebay.
That's Abbas not the NATS one before TELS spit their coffees out!

Sir George Cayley

[Contacttower]

BTW don't wait for SAM to come on the market. Compton NDB is on Ebay.
That's Abbas not the NATS one before TELS spit their coffees out!



So that's why I couldn't find it the other day!

Although I can't find it on ebay either at the moment...:{

[glazer]

It has recently been reported (AOPA magazine) that the CAA are intending to drop the ADF requirement for flying IFR in CAS early 2008. If true, then good riddance to an old-fashioned, outdated, unnecessary and actually potentially dangerous instrument.:D

[glazer]

Are you suggesting, by the way, that the NDB might be so inaccurate that it and the GPS might disagree violently? If so, why on earth are we basing approaches on them?


Some years ago I tried a practice NDB approach into Gloucester. Fortunately it was in VMC because the needle in fact guided me in the opposite direction to what was intended and had I been doing this for real in IMC I would have eneded up in the hills. The problem was caused I believe by interference from a radio station in France. NDB approach in using an ADF down to minimums, no thanks. :{

[IO540]

As I keep repeating :ugh: the ADF may go away as a mandatory enroute carriage requirement but it won't go away for approaches.

So, by all means chuck it out but then you won't be able to fly a huge number of approaches around the UK and Europe, for the foreseeable future.

In practice, most smart pilots know the NDB/ADF is a load of crap when it comes to accuracy and they fly NDB approaches using either the GPS overlay or using the OBS mode of the GPS, just checking the ADF at the start of the descent. This is legal because the regs don't state what equipment is to be used (and AFAIK flying an NDB approach using the FMS is a SOP in the airline business) but IMHO flying an NDB approach without carrying an ADF is probably illegal, especially in CAS.

[bookworm]

It has recently been reported (AOPA magazine) that the CAA are intending to drop the ADF requirement for flying IFR in CAS early 2008. If true, then good riddance to an old-fashioned, outdated, unnecessary and actually potentially dangerous instrument.

That's for enroute carriage.

Try finding an approach you can fly without an ADF. Without overlay approaches and/or GPS substitution for ADF/DME (both permitted in the US), you'll still need an ADF from a practical point of view in the UK.

[tmmorris]

Exactly right, IO540: my GPS converts an NDB approach into basically a VOR/DME one, with HSI presentation. So much simpler...

Tim

[glazer]

IO540:A very interesting distinction between "using" and "carrying"!! Does "carrying" also imply that it must actually be fixed in place and does it mean that it must actually be working? Can I just carry an old dead one in my aircraft?;)