Future of NDB/ADF
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Future of NDB/ADF
I've heard somewhere that the CAA is considering withdrawing the need for NDBs. Can't find anything in their website.
Can anybody throw some light on this?
Can anybody throw some light on this?
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The long term plan by Eurocontrol & al. is to go 100% satnav. There used to be a presentation on it somewhere on the net. I'll post link if I can find it.
...but I'm sure bookworm will be here soon filling us in on the details.
...but I'm sure bookworm will be here soon filling us in on the details.
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I went to a Eurocontrol nav workshop recently.
There are all kinds of "plans" going around, some less bizzare than others.
NDBs are a bit of a special case because they are manifestly not needed for anything, and IMHO they will go within 10-20 years.
The UK is almost unique in requiring the carriage of an ADF for all IFR in all classes of CAS. Switzerland was the other one but it allows IFR GPS substitution, USA-style. This requirement will disappear, I am sure, within the next few years.
As regards other navaids, some must remain. Airliners (CAT) have INS but this requires DME-DME fixes for reasonable accuracy. Eurocontrol have one plan under which all navaids except DME are dismantled and most ATC radar too (because airlines want lower enroute charges) but hundreds of new DMEs are installed to provide a uniform DME coverage for CAT.
VORs are quite expensive and they may go within say 20 years.
The practical reality is that the IFR world is wholly RNAV (INS+DME, or GPS) with all flight using virtual waypoints (which occassionally are real VORs etc but almost nobody tunes in the actual navaids) and VORs/NDBs are an irrelevance except on instrument approaches.
But there remains the perpetual chestnut of what will happen if GPS fails.
"The Plan" is that CAT will use a combination of INS+DME+ATC radar, while non-INS traffic (GA, up to light jets) will use ATC radar to get back down. One perceived problem with this is that if airlines get their way and most ATC radar coverage has been dismantled and replaced with ADS-B (hey, this is Brussels) then there won't be enough ATC+radar capability for the thousands of VLJs (yes, Brussels have not yet realised that Eclipse has gone bust, the air taxi model is dead and always was, etc, etc, etc) to get back down.
Yet anybody actually working in IFR ATC will say that the chance of ATC radar disappearing is nil, which IMHO is bang on. Radar will always be needed for national security reasons.
So I don't see much changing, but I can see non-approach NDBs (e.g. WCO) disappearing, with the IFR ADF carriage requirement.
There was some subtle reason why the CAA didn't want to remove this requirement but I cannot remember what it was.
There are all kinds of "plans" going around, some less bizzare than others.
NDBs are a bit of a special case because they are manifestly not needed for anything, and IMHO they will go within 10-20 years.
The UK is almost unique in requiring the carriage of an ADF for all IFR in all classes of CAS. Switzerland was the other one but it allows IFR GPS substitution, USA-style. This requirement will disappear, I am sure, within the next few years.
As regards other navaids, some must remain. Airliners (CAT) have INS but this requires DME-DME fixes for reasonable accuracy. Eurocontrol have one plan under which all navaids except DME are dismantled and most ATC radar too (because airlines want lower enroute charges) but hundreds of new DMEs are installed to provide a uniform DME coverage for CAT.
VORs are quite expensive and they may go within say 20 years.
The practical reality is that the IFR world is wholly RNAV (INS+DME, or GPS) with all flight using virtual waypoints (which occassionally are real VORs etc but almost nobody tunes in the actual navaids) and VORs/NDBs are an irrelevance except on instrument approaches.
But there remains the perpetual chestnut of what will happen if GPS fails.
"The Plan" is that CAT will use a combination of INS+DME+ATC radar, while non-INS traffic (GA, up to light jets) will use ATC radar to get back down. One perceived problem with this is that if airlines get their way and most ATC radar coverage has been dismantled and replaced with ADS-B (hey, this is Brussels) then there won't be enough ATC+radar capability for the thousands of VLJs (yes, Brussels have not yet realised that Eclipse has gone bust, the air taxi model is dead and always was, etc, etc, etc) to get back down.
Yet anybody actually working in IFR ATC will say that the chance of ATC radar disappearing is nil, which IMHO is bang on. Radar will always be needed for national security reasons.
So I don't see much changing, but I can see non-approach NDBs (e.g. WCO) disappearing, with the IFR ADF carriage requirement.
There was some subtle reason why the CAA didn't want to remove this requirement but I cannot remember what it was.
Last edited by IO540; 18th Apr 2009 at 08:22.
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Interesting...................... Having used ADF in anger only twice in 10,000 hours of European flying I have to question why we have it, a bit of back up is all I can think of................... apart from being able to get the cricket scores!
However I would like to see the CAA get there act together on the requirement to have ADF for flight in controlled airspace, a number of American airlines flying into the UK don't have ADF and yet they still fly in UK class A airspace. In fact this is one of the reasons that LGW was one of the first places to get a GPS approach!
It seems a little strange that an American airliner can fly in UK class A airspace without ADF yet a British airliner cant.
Can only think this is the result of the ex-navigators still reminiscing in the aviation house canteen about the days of the HP Hastings and trips up the north sea from Finningley.
However I would like to see the CAA get there act together on the requirement to have ADF for flight in controlled airspace, a number of American airlines flying into the UK don't have ADF and yet they still fly in UK class A airspace. In fact this is one of the reasons that LGW was one of the first places to get a GPS approach!
It seems a little strange that an American airliner can fly in UK class A airspace without ADF yet a British airliner cant.
Can only think this is the result of the ex-navigators still reminiscing in the aviation house canteen about the days of the HP Hastings and trips up the north sea from Finningley.
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It may all become rather academic in the next few years as quite a few of the UK NDBs have already been withdrawn, with a few others effectively withdrawn although officially u/s. I certainly can't recall any new NDBs beng announced. Maybe we'll find the requirement removed when they realise there are no ground stations left?
Personally, considering the volume and complexity of today's CAS, I'd prefer the accuracy of VOR/DME and GPS as belt and braces back-up to visual navigation. Although the receivers are handy for thunderstorm detection - as well as the cricket!
Personally, considering the volume and complexity of today's CAS, I'd prefer the accuracy of VOR/DME and GPS as belt and braces back-up to visual navigation. Although the receivers are handy for thunderstorm detection - as well as the cricket!
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It is an interesting argument , the whys and wherefores of these miserable little bits of kit they are like marmite. I personally hate the bloody stuff .
If it wasnt for these things the IR could be condensed into about 20 hours ish.
The daft thing is if you look at the only approved gps approach in the uk (I think its the only one) Shoreham have alook at the missed approcah procedure , back to the beacon
Bizarre
If it wasnt for these things the IR could be condensed into about 20 hours ish.
The daft thing is if you look at the only approved gps approach in the uk (I think its the only one) Shoreham have alook at the missed approcah procedure , back to the beacon
Bizarre
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Technically NDBs are required for offshore approaches to platforms although there is no practical reason why we couldn't use GPS. Offshore we more or less have to have GPS and it is great. But we have either an on shore NDB or the appropriate rig NDB tuned at all times. It is always nice to have a spare needle pointing to where you want to go. Given we only have one GPS and often no radar or VOR coverage, the NDB is the only back up we have.
I am sure the days of the NDB are numbered, but it seems a shame to loose something which is so simple to use. Yes it is not terribly accurate and has some gottchas, but it will get you to a position where more sophisticated nav aids will get you in. Having said that the trial GPS approach for Durham Tees Valley had higher minima than the NDB approach did. Let's hope that when we finally get widespread GPS approaches the minima are at not worse than the anitque it replaces. Otherwise we'll only have backward progress.
I am sure the days of the NDB are numbered, but it seems a shame to loose something which is so simple to use. Yes it is not terribly accurate and has some gottchas, but it will get you to a position where more sophisticated nav aids will get you in. Having said that the trial GPS approach for Durham Tees Valley had higher minima than the NDB approach did. Let's hope that when we finally get widespread GPS approaches the minima are at not worse than the anitque it replaces. Otherwise we'll only have backward progress.
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Future of NDB/ADF
At present, the majority of Missed Approaches require a turn back to an NDB, even if you are using, say, an ILS/DME approach. If and when the NDBs bite the dust, will the missed approach be based on GPS? If so, what constitutes an acceptable GPS system in the a/c? As a GA/IMC pilot my hand held G96 would probably get the thumbs down
, but would the fixed G430 be acceptable?
, but would the fixed G430 be acceptable?
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We have an ILS and NDB approach on one end and a single NDB approach to the other.
I suspect that as soon as GPS approaches are approved UK wide, we'll keep the NDB until it keels over and then it won't be replaced.
The NDB approaches are extensively used by every type of a/c, from C150s to B767s, but most operators prefer to take the ILS and a tailwind of up to 10kts if we aren't busy with departures.
From an airfield perspective, we don't technically need an NDB now, but to commit ourselves to not having one before GPS approaches are approved would require us to man 2 radar postions at all times, one for approach/LARS and the other for SRA's - that isn't going to happen in these economic times.
Word on the street is that once GPS approaches are approved in the UK and providing that each individual airfield to present a safety case, the minima will be reduced to below that of the previous NDB approach.
I suspect that as soon as GPS approaches are approved UK wide, we'll keep the NDB until it keels over and then it won't be replaced.
The NDB approaches are extensively used by every type of a/c, from C150s to B767s, but most operators prefer to take the ILS and a tailwind of up to 10kts if we aren't busy with departures.
From an airfield perspective, we don't technically need an NDB now, but to commit ourselves to not having one before GPS approaches are approved would require us to man 2 radar postions at all times, one for approach/LARS and the other for SRA's - that isn't going to happen in these economic times.
Word on the street is that once GPS approaches are approved in the UK and providing that each individual airfield to present a safety case, the minima will be reduced to below that of the previous NDB approach.
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Goatface,
From an airfield perspective, we don't technically need an NDB now,
Does your airfield presently use the NDB as the Missed Approach fix? If so, if you don't really need an NDB now, would you be able to accept an a/c for an ILS approach if their ADF was either inop, or not even fitted?
From an airfield perspective, we don't technically need an NDB now,
Does your airfield presently use the NDB as the Missed Approach fix? If so, if you don't really need an NDB now, would you be able to accept an a/c for an ILS approach if their ADF was either inop, or not even fitted?
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I should think that any airport with radar does not need an NDB for the missed approach, because they would vector the traffic.
You can bet Heathrow is never going to send somebody back to the NDB. Especially as, I also bet, a % of the airliners landing there right now don't have an ADF... not that it matters because the NDB will be in their GPS database.
I don't know how these things work when it comes to official navaid planning but my guess would be that NDBs will remain as approach fixes, because the alternative is a marker beacon and those have mostly vanished in Europe. But with DME you don't need an approach fix, and almost every ILS has a DME.
Is a DME cheaper than an NDB? It is probably similar, and much more useful.
I cannot believe that people flying to N Sea platforms think the NDB will be a good backup. If you get a TS nearby, the needle will point just about anywhere. And there is no "valid" flag so it is a case of "if the needle agrees with the GPS, fine, and if it doesn't agree, you ignore it".
So that leaves just the missed approach case. This can be dealt with (on the approach plate) by intercepting some VOR radial and flying a hold there - flying an "enroute" hold around some holding fix defined by a VOR is standard IR staple diet
The VOR could be miles away; nowhere near the airport, so the airport isn't paying for it.
You can bet Heathrow is never going to send somebody back to the NDB. Especially as, I also bet, a % of the airliners landing there right now don't have an ADF... not that it matters because the NDB will be in their GPS database.
I don't know how these things work when it comes to official navaid planning but my guess would be that NDBs will remain as approach fixes, because the alternative is a marker beacon and those have mostly vanished in Europe. But with DME you don't need an approach fix, and almost every ILS has a DME.
Is a DME cheaper than an NDB? It is probably similar, and much more useful.
I cannot believe that people flying to N Sea platforms think the NDB will be a good backup. If you get a TS nearby, the needle will point just about anywhere. And there is no "valid" flag so it is a case of "if the needle agrees with the GPS, fine, and if it doesn't agree, you ignore it".
So that leaves just the missed approach case. This can be dealt with (on the approach plate) by intercepting some VOR radial and flying a hold there - flying an "enroute" hold around some holding fix defined by a VOR is standard IR staple diet
The VOR could be miles away; nowhere near the airport, so the airport isn't paying for it.
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IO540,
I didn't say it was a good back up, it is the only (but adequate) back up nav aid. I am sure times will change. But to be honest, I don't find the NDB to be a rubbish as everyone else seems to.
I didn't say it was a good back up, it is the only (but adequate) back up nav aid. I am sure times will change. But to be honest, I don't find the NDB to be a rubbish as everyone else seems to.
I find them useful for situational awareness, I almost always have one tuned to the airfield. As droopystop mentions, it's nice to have a needle pointing in the direction you want to go. My NDB tracking and holding abilities leave a lot to be desired however!
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As above, I always have it tuned to the airfield's NDB if it has one. It's great in case the **** hits the fan during the departure as you are (well, I am anyway) annoyingly likely to lose spatial awareness while handling the emergency. A quick look at the needle tells you which way is back to the deck.
Of course, if you have a spare RMI or HSI (i.e., one not being used for flying the SID) you could use that instead, slaved to a VOR or GPS.
Plus, you can't listen to the news on a GPS
Of course, if you have a spare RMI or HSI (i.e., one not being used for flying the SID) you could use that instead, slaved to a VOR or GPS.
Plus, you can't listen to the news on a GPS
Don't most UK approaches involve an NDB for IAF?
Pardon what might be a dumb question from an IMCR-only pilot.
In practice, on most approaches one gets radar vectors onto the final approach segment. However, in my very limited experience, if you do the full approach, most UK approaches involve an NDB as the IAF, as well as in the Missed Approach. A minority of approaches have a VOR for the IAF and Missed Approach. Or have I got that wrong? E.g. (taking a sample) Bristol, Bournemouth, Southampton, Exeter, Norwich, Cambridge, Shoreham (other than GPS), Southend, Manchester, London City... all have an NDB as the IAF. Biggin doesn't, as it's got a VOR on the field.
Is the assumption that NDBs will remain part of these approaches? Or if they are phased out, will we be required to be able to fly GPS approaches? Or will every approach need radar vectors to final approach?
In practice, on most approaches one gets radar vectors onto the final approach segment. However, in my very limited experience, if you do the full approach, most UK approaches involve an NDB as the IAF, as well as in the Missed Approach. A minority of approaches have a VOR for the IAF and Missed Approach. Or have I got that wrong? E.g. (taking a sample) Bristol, Bournemouth, Southampton, Exeter, Norwich, Cambridge, Shoreham (other than GPS), Southend, Manchester, London City... all have an NDB as the IAF. Biggin doesn't, as it's got a VOR on the field.
Is the assumption that NDBs will remain part of these approaches? Or if they are phased out, will we be required to be able to fly GPS approaches? Or will every approach need radar vectors to final approach?
Last edited by FREDAcheck; 19th Apr 2009 at 13:20.
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I think the short answer is that nobody knows, because there are competing pressures.
The airlines, according to Eurocontrol, want a purely RNAV environment (which to them means INS, and loads of DMEs all over Europe so their INS works accurately; one Eurocontrol proposal was for 300 new DMEs around Europe) and they don't want radar or any navaids other than ILS. This, it is claimed, will reduce the IFR enroute charges. Eurocontrol seems to have bought into this "dismantle most radar and navaids" way of thinking - at least to the extent of talking about it, running workshops (at which the proposal is roundly rubbished, especially the radar stuff), and publishing proposals.
But the national powers to be cannot simply implement this because there is other traffic "up there" also, plus there are ICAO obligations, etc.
Then there is the gap between published approaches and what is actually flown. At any major airport, there is radar, and almost nobody is flying the published (procedural) approaches, and it is these which use the navaids. Generally, the place has an ILS and you get vectored to the localiser. ATC like it because it gives them total control, and pilots like it because they have very little to do. But there is often training traffic which tends to be banging the navaids. Or the radar could be out of service (because it's broken or due to staff shortages). Or the ILS is only on one runway direction, so the navaids have to be there for when the wind blows the other way (even if, like say Bournemouth, ATC give you radar vectors onto the "NDB inbound").
That's why the death of the NDB has been forecast for the past 50 years
The airlines, according to Eurocontrol, want a purely RNAV environment (which to them means INS, and loads of DMEs all over Europe so their INS works accurately; one Eurocontrol proposal was for 300 new DMEs around Europe) and they don't want radar or any navaids other than ILS. This, it is claimed, will reduce the IFR enroute charges. Eurocontrol seems to have bought into this "dismantle most radar and navaids" way of thinking - at least to the extent of talking about it, running workshops (at which the proposal is roundly rubbished, especially the radar stuff), and publishing proposals.
But the national powers to be cannot simply implement this because there is other traffic "up there" also, plus there are ICAO obligations, etc.
Then there is the gap between published approaches and what is actually flown. At any major airport, there is radar, and almost nobody is flying the published (procedural) approaches, and it is these which use the navaids. Generally, the place has an ILS and you get vectored to the localiser. ATC like it because it gives them total control, and pilots like it because they have very little to do. But there is often training traffic which tends to be banging the navaids. Or the radar could be out of service (because it's broken or due to staff shortages). Or the ILS is only on one runway direction, so the navaids have to be there for when the wind blows the other way (even if, like say Bournemouth, ATC give you radar vectors onto the "NDB inbound").
That's why the death of the NDB has been forecast for the past 50 years
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Insurance for NDB
I used to maintain the NDB at our airfield, but now the Bureaucrats want a £1000 a year public liability insurance. 
This is just to much for the club, so naturaly, taken down.
The next thing will be paying the Government for bandwidth usage. So the radio will be the next to go. No info service. I supose we will do the microlight thing and use 128.92 as a comms frequency.
NDB might not be used much but is a good back up when the weather is poor.
This is just to much for the club, so naturaly, taken down.The next thing will be paying the Government for bandwidth usage. So the radio will be the next to go. No info service. I supose we will do the microlight thing and use 128.92 as a comms frequency.
NDB might not be used much but is a good back up when the weather is poor.
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Hi all
This was the CAA's consultation sent out last year about increasing B-RNAV down below FL95 (so GNS 530/430 KLN90's all around) and suggesting various stages of NDB removal.
Consultation ? Introduction of BRNAV below FL 95 | Consultations | CAA
This was the CAA's consultation sent out last year about increasing B-RNAV down below FL95 (so GNS 530/430 KLN90's all around) and suggesting various stages of NDB removal.
Consultation ? Introduction of BRNAV below FL 95 | Consultations | CAA
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NDB withdrawal
Like it or not we tend to follow changes made in the USA economically, scientifically, aeronautically etc...(although we hate to admit it and although those changes are not always for the best).
I remember the yanks being amazed that we were still using NDBs 5 years ago during my last type rating. What about all those NDB holds and approaches carried out during the IR? What will IR training consist of in the future?
As for DME, synthetic GPS-based DME seems an acceptable alternative.
I remember during my IR training the instructor would tell me to lift the foggles up after a procedural NDB approach where I had kept the needle centred and thought I was spot-on the centreline and had made a great job of things. When the shades were lifted I would be 2 fields off the centreline with the airport disappearing under a wing. NDB approaches are bloody awful as stand alone approaches in poor weather.
Incidentally it did make me laugh reading the preaching in this month's GASIL about not relying on GPS. I can't remember the exact wording and no longer have it as it hit the bin shortly after I read it. The anti-GPS dinosaurs are still out there, bless 'em...
SB
I remember the yanks being amazed that we were still using NDBs 5 years ago during my last type rating. What about all those NDB holds and approaches carried out during the IR? What will IR training consist of in the future?
As for DME, synthetic GPS-based DME seems an acceptable alternative.
I remember during my IR training the instructor would tell me to lift the foggles up after a procedural NDB approach where I had kept the needle centred and thought I was spot-on the centreline and had made a great job of things. When the shades were lifted I would be 2 fields off the centreline with the airport disappearing under a wing. NDB approaches are bloody awful as stand alone approaches in poor weather.
Incidentally it did make me laugh reading the preaching in this month's GASIL about not relying on GPS. I can't remember the exact wording and no longer have it as it hit the bin shortly after I read it. The anti-GPS dinosaurs are still out there, bless 'em...
SB