UK NDB only timed approaches

[Obs cop]

Hi all,

Hoping someone can help with a query.

Are there an NDB only approaches left in the UK? In other words where the approach does not have a co-located DME and therefore timing must be used for a missed approach point rather than a range.
I'm just curious as I used to practice them during my IMC and subsequent IR training using the CT NDB at Coventry, but that was over a decade ago.

Thanks,
Rich

[Jan Olieslagers]

Excuse me for not having a real answer. Only in the margin:
On the general trend, NDB's are a thing of the past. In Europe at least, and probably elsewhere too, they are being phased out quite rapidly.
The UK is of course a somewhat peculiar place - by which I mean nothing negative! - but sooner or later the NDB's will be going there, too. Fazit: even if some remain today, don't count on them being there tomorrow. The future is all for SatNav (called "GPS" by some) which is cheaper both for operators and for users, and more accurate.

[Captain-Random]

Hi all,

Hoping someone can help with a query.

Are there an NDB only approaches left in the UK? In other words where the approach does not have a co-located DME and therefore timing must be used for a missed approach point rather than a range.
I'm just curious as I used to practice them during my IMC and subsequent IR training using the CT NDB at Coventry, but that was over a decade ago.

Thanks,
Rich


St Mary’s on the Isles of Scilly EGHE has one for RW 32 & 27

[Sleepybhudda]

As mentioned earlier,

EGHE St Marys on the Isle of Scilly

Also;
EGNC Carlisle
EGJA Alderney

Links to the AIP and aerodrome approach plates
https://www.aurora.nats.co.uk/htmlAIP/Publications/2020-11-05-AIRAC/html/index-en-GB.html

[Rt Hon Jim Hacker MP]

Bloody death traps. Shame on any airport that even has a published approach chart.

Before all the heroes come along, yes I can fly one. But they are dangerous by design. We can do far better in this day and age.

[CJ1234]

Quite agree. the NDB should have gone the way of the dodo decades ago.

[ShyTorque]

NDB? Luxury. The RAF was still carrying out QGH letdowns into grass airfields in the 1990s. We had to, we had fly above and in cloud to instruct in SEP aircraft with no radio nav aids at all and no radar service. Looking back, madness. We used to ask for true bearings from two airfields to keep ourselves out of an airway adjacent to our local flying area.

[Fl1ingfrog]

Most published procedures include an alternative timed procedure without DME.

Bloody death traps. Shame on any airport that even has a published approach chart.

Before all the heroes come along, yes I can fly one. But they are dangerous by design. We can do far better in this day and age.

What a strange thing to say. Follow the procedure in accordance with the design and above all comply with the published minima. If they weren't safe they wouldn't be there.

[havick]

Bloody death traps. Shame on any airport that even has a published approach chart.

Before all the heroes come along, yes I can fly one. But they are dangerous by design. We can do far better in this day and age.

Coastal refraction flying the NDB into Honiara was very noticeable.

That being said, design and certification would have taken that into account. So as some poster said above, any NDB approach flown as published shouldn’t be unsafe.

[Tinstaafl]

If they were designed i.a.w. the required standards and flown that way then they were no less safe than any other approach designed to the same standard(s).

But to address the original question, Scatsta in Shetland only had an NDB approach and an SRA approach. That airport recent lost all its customers so it may not have them published anymore. But when I was based in Shetland the NDB approach was just a normal thing.

[Rt Hon Jim Hacker MP]

Most published procedures include an alternative timed procedure without DME.



What a strange thing to say. Follow the procedure in accordance with the design and above all comply with the published minima. If they weren't safe they wouldn't be there.

That’s exactly the attitude I expected. Perhaps you should do a bit of research on the accident statistics of non precision approaches compared to precision approaches. I’ve flown thousands of both over the years and I know what I would prefer.

Do you think that those NPA’s that ended up in an accident we’re just being flown by people that didn’t know what they were doing? They woke up in the morning and set off flying to have an accident or incident. The simple fact is that a timed NDB is dangerous. Try flying one near a thunderstorm. Needle swinging around 10 to 20 degrees all the time. They also encourage the “dive and drive” type of approach.

They are not fit for purpose in this day and age. The world has moved on.

[chevvron]

Excuse me for not having a real answer. Only in the margin:
On the general trend, NDB's are a thing of the past. In Europe at least, and probably elsewhere too, they are being phased out quite rapidly.
The UK is of course a somewhat peculiar place - by which I mean nothing negative! - but sooner or later the NDB's will be going there, too. Fazit: even if some remain today, don't count on them being there tomorrow. The future is all for SatNav (called "GPS" by some) which is cheaper both for operators and for users, and more accurate.
I read somewhere recently that the UK CAA require licensed airfields to have a notified means of location even for VFR airfields; the most basic of these means is to have an NDB on the airfield with or without DME or alternatively VDF, however some airfields have decided to de-commision their NDBs where they have a VOR/DME located not too far away, having discussed it with operators and found that very few actually use the NDB for its original purpose plus you have to pay for a license and regular maintenance or repairs (many are getting quite old) and VDF cannot be used effectively at FISO airfields as the AFISO cannot pass QDMs, only QDRs.

[Floppy Link]

Scatsta in Shetland only had an NDB approach and an SRA approach. That airport recent lost all its customers so it may not have them published anymore.

Scatsta is no more, closed on 30 June :uhoh:

[Hot 'n' High]

..... Follow the procedure in accordance with the design and above all comply with the published minima. If they weren't safe they wouldn't be there.

Agreed re Safety. However, not so convinced on their usefulness particularly given some MDAs necessary to preserve Safety!! And following the needle rarely gets you to where the bit of paper suggests - certainly, via the nice straight line indicated on the chart. Recall one OPC using an NDB. ATC even asked where we were going - to which the Examiner instantly replied on my behalf and in my defence with more than a hint of tetchiness "We are following your NDB!" :ok:

[BackPacker]

Sometimes I'm asking myself if it's not better to make the NDB approach to the opposing runway by default, and then do a circle to land. Once you reach minima it seems like with a circle to land there's a lot less manoeuvering required than with a supposedly straight-in NDB. And you've got more time for that as well. And it's not going to make a practical difference to the minima anyway.

With NDBs routinely positioned on the airfield itself, your MAPt is also above the airfield itself so if you become visual just before MAPt there's no way you'll be able to land from there so you'll need to fly a full circuit...

[Fl1ingfrog]

I read somewhere recently that the UK CAA require licensed airfields to have a notified means of location even for VFR airfields;

No they don't.

so if you become visual just before MAPt there's no way you'll be able to land from there so you'll need to fly a full circuit...

You can plan or opt to do this always if you wish, a cloud break has always been the main purpose of an NDB let down..

With NDBs routinely positioned on the airfield itself,......

Most airfields dispensed with their off field 4nm NDB many years ago. The cost of maintaining and paying rent to a farmer for an off field piece of land became surplus to need. An NDB beacon sited on your own airfield land is a relatively cheap piece of kit to buy and with only a minor associated cost to licence and maintain. GNSS approaches will in time replace all land based expensive systems of course but meanwhile the NDB is a great backup for initial positioning.

[golfbananajam]

Hi all,

Hoping someone can help with a query.

Are there an NDB only approaches left in the UK? In other words where the approach does not have a co-located DME and therefore timing must be used for a missed approach point rather than a range.
I'm just curious as I used to practice them during my IMC and subsequent IR training using the CT NDB at Coventry, but that was over a decade ago.

Thanks,
Rich


Although I believe it's not a published procedure, Leicester used to have one, not sure if it's still there. Might be worth giving them a ring.

[SignalSquare]

Great for training spatial awareness!

[Private jet]

I remember spending time, and much more importantly a lot of money learning how to do these on my IR course 20 years ago. NDB holds too, gate angles, all that stuff. Nonsense really in a light aircraft because if the crosswind is too strong flying the racetrack is impossible due to the low speed of the aircraft. Having said all that I can't remember ever doing one in "real life" afterwards, holds at RNAV waypoints by FMS, and approach, everywhere we went sans an ILS had at least VOR/DME or localiser or LNAV and later LPV of course. Some places though you just have to look out of the window(!) eg Samedan. A relic from the 50's and the world has moved on.

[ShyTorque]

I read somewhere recently that the UK CAA require licensed airfields to have a notified means of location even for VFR airfields; the most basic of these means is to have an NDB on the airfield with or without DME or alternatively VDF, however some airfields have decided to de-commision their NDBs where they have a VOR/DME located not too far away, having discussed it with operators and found that very few actually use the NDB for its original purpose plus you have to pay for a license and regular maintenance or repairs (many are getting quite old) and VDF cannot be used effectively at FISO airfields as the AFISO cannot pass QDMs, only QDRs.

My local licensed (grass) airfield has never had an NDB, or any other method of location. It’s been there since the 1930s. I can think of another that used to have an NDB just outside it’s boundary (I always dialled it up while transitting close by) but it went off line without much warning a few years ago and seems that it’s gone forever.

[ShyTorque]

Although I believe it's not a published procedure, Leicester used to have one, not sure if it's still there. Might be worth giving them a ring.

Yes, the NDB “LE” on 383.5 is still there. It’s not supposed to be used other than in VMC, so not too useful.

[Rt Hon Jim Hacker MP]

Used to tune up Atlantic 252 on the night crossings from North America years ago. Bit of radio gaga....

[Genghis the Engineer]

We used to have one at Cranfield on 21 and the CIT. Checking, it vanished at some point I wasn't paying attention, but the footprint is I think the same if you can find an old plate.

G

[excrab]

Gloucester still has a published NDB approach based on timing only, in addition to the NDB/DME approaches for 09 and 27.

[ETOPS]

During my IR training I was taught to keep the NDB ident running in my audio as there was no failure flag. Not long afterwards, whilst carrying out such an approach, the audio suddenly ceased - going around I told ATC that their beacon was u/s but was surprised to be told “no it hasn’t “ followed a few seconds later by “ooops you’re right.”
Was wary of them from then on ..,

[TheOddOne]

Most airfields dispensed with their off field 4nm NDB many years ago.

Try the dreaded EX at Exeter. No idea why it hasn't been moved on to the airfield. Character building stuff, doing an NDB approach with the beacon behind you...

TOO

[Tinstaafl]

For some reason the US is really fond of break away approaches and timing to the MAPt, instead of break towards approaches with the beacon on the field also serving as the MAPt.

[FullWings]

I’ve done a fair few for real but now with GPS what’s the point? I totally agree with the Rt Hon that NPAs have a far higher historical risk of CFIT, given an equal competence of operator. LNAV/VNAV minima are almost always better and in the commercial world, CDAs are the way we fly.

Good riddance!

[tinmug]

It must have been about 10years ago they shut down the Charlie Tango at Coventry. Then Mercia sound 1359 AM located their transmitter just down the road in line with 23 and you could ident it from the music on their repetative playlist.

[Rt Hon Jim Hacker MP]

Here's my thoughts on NDB's...

A couple of years ago, the VOR was off in KGS. For the whole summer. KGS seems a popular night trip. Crap runway lights and non-existent approach lighting. We were banned from doing night visuals by our "esteemed" management. Descending into a visual circuit was considered too risky. The only alternative was a cloud break NDB which left you in the middle of flipping nowhere. Have a look at the plate. The least risk option was to fly the VOR in managed, but not entirely legal as it was an overlay. Dual GPS and all the bells and whistles. Aircraft and crew RNP/AR. More than happy to fly the RNAV approaches into Innsbruck relying on the same bits of kit without raw data back up the very next day. Go figure....

Kind of like you are driving the most bang up to date car with your precious family onboard. But you are about to descend the Stelvio Pass. At night. It's wet and maybe slippery. Who would pull over and replace their bright and shiny Bi-Xenon headlights with the Lucas light bulbs from 1971? While you are it, disable the ABS. Why stop there? Traction control is for pussies. Airbags? Pah! You get the idea.

The world has moved on. Everyone of us (from IR students in a C152 to experienced crews in a Boeing or Airbus) deserve better than NDB approaches. They belong in history.

[Fl1ingfrog]

Great for training spatial awareness!

In the grand old days of instructing it was necessary to hold at least a IMC rating. To upgrade from Assistant Flying Instructor (AFI) to Flying Instructor (FI) it was necessary to undertake an upgrade test. It was commonplace prior to this assessment to complete a course to teach applied instrument flying (IMC rating). On day one of my course the FIC instructor asked me what the main basis of my IMC training was: "NDB sir" I replied. His comment: "thank God for that, you will have spatial awareness, the VOR/ILS lot never know where they are".

What tells us much of yesterday times is the term given to the NDB onboard equipment that is: Automatic Direction Finding (ADF) radio. Hardly that of course in todays meaning of the words.

[Genghis the Engineer]

You called a civilian instructor Sir ????

I think that NDB approaches have value, maybe for SA, although I'm not altogether convinced by your argument that they give better SA than other systems - I don't think it gives me anything I don't get from, say a VOR/DME.

But the NDB is the most basic bit of navigational technology imaginable. It costs a fraction to install and maintain what a VOR or ILS does, an NDB basically needs a few hundred pounds worth of hardware and a power supply. I'd argue that it's the best possible backup to GPS because it's the cheapest and most robust. Yes, it is also very hard work to fly, but on the other hand once you've flown a timed NDB approach, everything else is easy - so it's not a bad training tool.

G

[VariablePitchP]

Most published procedures include an alternative timed procedure without DME.



What a strange thing to say. Follow the procedure in accordance with the design and above all comply with the published minima. If they weren't safe they wouldn't be there.

That’s a very strange thing to say. If it was that easy for people to just follow the procedure then there would never have been a crash involving an NDB. In the same way that if people just took off and landed properly there would never have been an incident during those phases of flight. The reality is, as you know, NDBs are harder to fly with far more opportunity for screwing up than an ILS or an RNav approach.

Assume you don’t wear a seatbelt when you drive? What would be the point, just don’t crash.

[MrAverage]

Genghis

CIT still on current Cranfield charts and, as far as I am aware, is still part of four of the procedural approaches. I haven't used it in a while though.

But perhaps you're saying Cranfield had two at one time?

[Fl1ingfrog]

Its not going to happen that NDB procedures will be introduced at places where they do not currently exist. For the future GNSS procedures are becoming the norm and costing circa £30,000 per approach. NDBs will naturally fade out as the replacement parts become harder to find and the units become obsolete. Where an ADF radio can be found they are also likely to be refurbished units and can cost as much to install in an aeroplane from scratch as some WAAS enabled GPS units so an unlikely choice.

Tragically deaths involving the ILS are not unknown. Sometime ago at the 1000ft (QFE) check I was far too low (calculated using the DME readout) and so stopped the descent. I spent some time maintaining the localiser but remained puzzled before instinctively tapping the indicator glass, the crossbar sprang to life upwards and banged hard against the stop. I regained the glideslope, continued, broke cloud and landed safely. The indicator was, of course, removed and sent to maintenance. Before DME we had the NDB as the outer (and btw inner markers at MDH/A) marker which also served for the NDB let down. The NDB was ubiquitous in serving as an airfield locator and an approach aid. GNSS also does all of this of course plus more.

Spatial awareness was always and remains the most critical skill of instrument flight whatever the kit in use. I often hear of the cross bars being referred to as "command" indicators. They are not and never intended to be, they are simply: course deviation indicators (CDI)

[Genghis the Engineer]

Genghis

CIT still on current Cranfield charts and, as far as I am aware, is still part of four of the procedural approaches. I haven't used it in a while though.

But perhaps you're saying Cranfield had two at one time?

When I did my IMCR at EGTC I was regularly flying a timed NDB approach on the CIT, that approach is now only an NDB/DME approach, which arguably isn't very helpful as whilst easier to fly, it does require a working DME in the aeroplane and they had the same footprint so could be run in parallel. So why they withdrew it, I've no idea.

G

[Mickey Kaye]

The AIP still has a timed option for runway 21 at Cranfield

[Genghis the Engineer]

Ah, I've just spotted it in the small print at the bottom of the plate, I stand corrected.

AIRCRAFT UNABLE TO RECEIVE DME

Fly outbound prior to Baseturn or extended outbound leg of the NDB(L) CIT hold for 2.5MIN (CAT A); 2MIN (CAT B); 1.5MIN (CAT C) descending to 2500(2142). Then turn right to intercept the FAT. When established inbound descend not below 1560(1202) at the SDF (NDB(L) CIT), then to MDH.

G

[Hew Jampton]

You called a civilian instructor Sir ????

I think that NDB approaches have value, maybe for SA, although I'm not altogether convinced by your argument that they give better SA than other systems - I don't think it gives me anything I don't get from, say a VOR/DME.

But the NDB is the most basic bit of navigational technology imaginable. It costs a fraction to install and maintain what a VOR or ILS does, an NDB basically needs a few hundred pounds worth of hardware and a power supply. I'd argue that it's the best possible backup to GPS because it's the cheapest and most robust. Yes, it is also very hard work to fly, but on the other hand once you've flown a timed NDB approach, everything else is easy - so it's not a bad training tool.

G
To differentiate between speaking to him as the FIC instructor/examiner as opposed to speaking to him as the pretend student.

[Mickey Kaye]

Its not going to happen that NDB procedures will be introduced at places where they do not currently exist. For the future GNSS procedures are becoming the norm and costing circa £30,000 per approach. (CDI)I think your being optimistic. I am hearing stories of upwards of 200K being spent on getting GNSS approach approval and it’s still not approved after some 6 years.

[Discorde]

There is (was) a benefit to the NDB being located remotely from the field (typically approx 4 nm and coincident with the OM): timing from the beacon inbound gave a reasonably precise indication of range from touchdown. The disadvantage was interpretation of the back bearing on the ADF - it was easy to turn 'the wrong way' when the bearing wasn't correct. When I was doing IR checking in the sim I would brief:

Under the mental workload it'll be easy to turn the wrong way if the back bearing isn't spot on. Here's a dodge to help you - once you've passed the beacon, set up a heading which gives you the required track inbound. In other words you can ignore the beacon for a while. By the laws of physics, if you departed the beacon on the correct track then your back bearing will be very close to what's required. Later on when you've got a moment or two you can sneak a look at the ADF indications to check all is well.

In the sim there was the bonus of HSI readout of track made good but even without FMC the concept still applies - fly a heading which you estimate will give you the correct track.

Arguably another benefit of NDB approaches is (was) sharpening basic handling skills (and boosting confidence), more so when manually flown. We used to call this 'airmanship'.

[Fl1ingfrog]

I think your being optimistic. I am hearing stories of upwards of 200K being spent on getting GNSS approach approval and it’s still not approved after some 6 years.


Well i can't understand how it should come to £200,000. There is no physical infrastructure to provide. All costs are in the fees: aerodrome survey, stakeholder consultation, approach design fees and of course the CAA approval charges. The CAA are being very difficult and obstructive which itself adds to the cost. They are demanding, for instance, that ATC are in place for all procedures, and do not accept trained A/G, although the regulations do not require it. This will inflate the cost a lot where ATC do not already exist and may have been included in the hearsay. My estimate may well be out of date but it was an estimated cost a few years ago when I had some direct involvement in the process.

EASA are very keen that small aerodromes have a GNSS procedures at low cost and the regulations do not require ATC. It is a poor reflection on the UK that there are so few GNSS procedures in place at small aerodromes. PPL/IR have done a lot of work in supporting and promoting them but continue to hit a brick wall. Meanwhile individuals are designing their own procedures which soon become widespread amongst locals at a particular aerodrome and flown regularly.

[Discorde]

Meanwhile individuals are designing their own procedures which soon become widespread amongst locals at a particular aerodrome and flown regularly.

Here's one I prepared for Turweston. The FF waypoints are labelled with the magnetic track to make good (ignoring noise abatement). The check alts are on QNH and equate to a 400ft/nm gradient. I can't guarantee its efficacy as I haven't flown it in IMC, so I'd only use it in extremis.


https://cimg6.ibsrv.net/gimg/pprune.org-vbulletin/946x561/turweston_gps_app_6ae86113037c382b4b9a18b6d24c388257a8590c.j pg

[Genghis the Engineer]

Discorde - does seem to be missing IAF, DA, and missed approach procedure. I'm not inherently against ad-hoc IAPs, but all of the formality that's there in the official ones is there for good reasons. Turweston is actually an excellent case, as it would readily lend itself to a day-only NPA, certainly GPS, and you might even get away with a VOR/DME approach onto 27 off BKY, and if you mandate ATC - well located where it is that could be provided by either Luton or Cranfield. But there is a lot more to a well designed IAP than simply flying GPS to the runway then landing.

(Also if you were in the vicinity desperate to land from above 8/8 you of course have multiple approaches at Cranfield, and if you're out of hours, can just apologise later after a safe landing!)

Fl1ingFrog - if you look up the dreadful mess made of the implementation of the IAP at Sywell, including correspondence from the airport accusing the CAA of trying to actively prevent it having any utility whatsoever (which they largely succeeded in achieving): the whole lot is online at the link below - you'll easily see where all the time and money went. The position isn't faintly defensible, but it's what it is has been to date.

https://www.caa.co.uk/Commercial-industry/Airspace/Airspace-change/Decisions/Sywell-Aerodrome-RNAV-arrival-procedures/

G

[jimtx]

Try the dreaded EX at Exeter. No idea why it hasn't been moved on to the airfield. Character building stuff, doing an NDB approach with the beacon behind you...

TOO
Push the head, pull the tail.

[FullWings]

Push the head, pull the tail.
Follow the pink string...?


I’ll show myself out.

[Fl1ingfrog]

if you look up the dreadful mess made of the implementation of the IAP at Sywell, including correspondence from the airport accusing the CAA of trying to actively prevent it having any utility whatsoever (which they largely succeeded in achieving)

Why an environmental impact is necessary for an aerodrome that already exists is beyond me. Unless they believe that an aircraft in cloud impacts the environment more that an aircraft that is clear of cloud. Outside controlled airspace and subject to the low flying regulations a pilot can fly where and whenever they wish and do. This simple fact seems to fly over these bureaucratic heads. The LNAV approach they have approved is non precision and can be flown with a simple single channel GPS (i.e. without WAAS enablement) and this is exactly the kind of approaches pilots are already making up for themselves.

Those at the CAA who are responsible are stark raving bonkers and just don't get it. Small aerodromes are completely out of their scope of understanding but we should be grateful for small gains I suppose. They will be quite pleased with themselves.

Of course a plus can be that the LNAV will be published and therefore will be found in a downloadable nav. pack. It must be flown as a non precision procedure and whilst the flight is depicted contemporaneously on the screen it will still only give lateral guidance. The descent however must be managed in an imprecise way without guidance. How is that safer than a LPV precision approach with the guided descent that was applied for? .

[FullWings]

I find it simultaneously uplifting and depressing when in contact with various parts of the CAA, as they manage to both look forward and backward at the same time. I think they are just beginning to realise that if they procrastinate for long enough, the rest of aviation goes off in whatever direction seems best at the time....

[carlmeek]

I just read the sywell documents. Wow.

I can’t help but feel CAA have completely lost the plot. It’s seemingly obsessive about safety but in the face of making it less safe by being so restrictive, causing people presumably to simply not use their procedures.

unless in a mountainous region, or severely complex, why on earth does a GNS approach need all this nonsense?

its like making bicycle helmets so complex to buy and fit that nobody wears them.

[tdbristol]

I must admit I have not had good experience of using NDB approaches in real IMC. Fortunately I have only used them when training (I have an IR(r) and FAA IR).
One on occasion coming into Filton rwy09 (shows how long ago it was) I was in real IMC; an instructor with me as it was a re-val test. I was flying it well - as the instructor agreed; needle just where it should be.
However, on shortish final ATC told us to abort and go around - we were 30degrees off track [still in solid IMC].
The weather was not that bad - only stratus cloud; no embedded CBs (maybe some CBs a distance away) - and the conclusion was coastal refraction plus the distant CBs had an effect (had seen coastal refraction effect at other times under the hood). Had to do an SRA in the end, which was not a problem, but it showed me how poor NDB guidance could be.

Second time was at Cardiff, went round the hold 10 times (!) in solid IMC, waiting for Easyjets to land etc. Another re-val test. Again the instructor agreed the ADF needle was spot on. Still on solid IMC we began the approach - all good - yet ATC told us to abort and go back to the hold as we were too far off track. (Ignored the ADF, just used the DI and timed the turn to do an ILS approach in the end.)

In both cases I would have had real problems if I had tried to land using the NDB alone.

I find it extraordinary that GNSS cannot be simply approved as an overlay on the same approach path as an existing NDB approach; surely all the issues of terrain clearance etc. have already been dealt with on the NDB approach? And GNSS is more accurate and reliable and not prone to NDB effects from a local CB or coastal refraction, and easier to interpret.
If there had been no NDBs and someone suggested NDBs now as an approach aid I would imagine that there would be many comments about its unreliability, safety issues etc. (certainly compared to GNSS) - not least from the CAA themselves.

[Genghis the Engineer]

Feel free to invent your own!

If I was creating my own ad-hoc IAP I absolutely would, but it troubles me that some people doing so, haven't. Missed approach procedure seems to be most often missing, followed by Decision Altitude.

Of course, for as long as CAA make it virtually impossible to get affordable approved IAPs, people will be just sticking a few waypoints in their GPS and hoping for the best.

G

[jmmoric]

Come to Greenland.

BGJN, BGSF, BGKK, BGBW, BGCO, BGQQ, BGUQ all have them, though better options are available.

The one in BGSF is used when the localiser or DME falls out of service, which rarely happens.

But as everywhere else, things are slowly replaces by GNSS or RNP approaches.

Some locations can handle LNAV/VNAV minima, others only LNAV. There's no SBAS or GBAS coverage yet, so for the LNAV/VNAV RAIM is required.

[Forfoxake]

I must admit I have not had good experience of using NDB approaches in real IMC. Fortunately I have only used them when training (I have an IR(r) and FAA IR).
One on occasion coming into Filton rwy09 (shows how long ago it was) I was in real IMC; an instructor with me as it was a re-val test. I was flying it well - as the instructor agreed; needle just where it should be.
However, on shortish final ATC told us to abort and go around - we were 30degrees off track [still in solid IMC].
The weather was not that bad - only stratus cloud; no embedded CBs (maybe some CBs a distance away) - and the conclusion was coastal refraction plus the distant CBs had an effect (had seen coastal refraction effect at other times under the hood). Had to do an SRA in the end, which was not a problem, but it showed me how poor NDB guidance could be.

Second time was at Cardiff, went round the hold 10 times (!) in solid IMC, waiting for Easyjets to land etc. Another re-val test. Again the instructor agreed the ADF needle was spot on. Still on solid IMC we began the approach - all good - yet ATC told us to abort and go back to the hold as we were too far off track. (Ignored the ADF, just used the DI and timed the turn to do an ILS approach in the end.)

In both cases I would have had real problems if I had tried to land using the NDB alone.

I find it extraordinary that GNSS cannot be simply approved as an overlay on the same approach path as an existing NDB approach; surely all the issues of terrain clearance etc. have already been dealt with on the NDB approach? And GNSS is more accurate and reliable and not prone to NDB effects from a local CB or coastal refraction, and easier to interpret.
If there had been no NDBs and someone suggested NDBs now as an approach aid I would imagine that there would be many comments about its unreliability, safety issues etc. (certainly compared to GNSS) - not least from the CAA themselves.

I am not an instrument-rated pilot (I gave up in the middle of my IMC training almost 30 years ago) but I think this account tells it's own story.

As CJ1234 said, "Quite agree. the NDB (approach) should have gone the way of the dodo decades ago."

[jimtx]

I am not an instrument-rated pilot (I gave up in the middle of my IMC training almost 30 years ago) but I think this account tells it's own story.

As CJ1234 said, "Quite agree. the NDB (approach) should have gone the way of the dodo decades ago."
Not until something else replaced them. More than once snow banks or snow ploughs somehow dissabled the ILS at DTW. Yes, dive and drive, push the head, pull the tail got us in. But it is good that nobody has to dive and drive anymore. That was a recipe for a mishap whether you were flying an NDB, VOR or LOC only.

[Genghis the Engineer]

Plenty of companies could make new, cheap NDBs, and it wouldn't be hard to make a more accurate better, modern ADF incorporated into other systems.

I'm entirely with jimtx on this. They are cheap and robust, need a fraction of the infrastructure of an ILS or VOR. We cannot just rely upon GPS as our sole mechanism for approaches - if that backup isn't NDB/ADF, what should it be?

G

[eckhard]

A second GNSS receiver capable of using GLONASS and Galileo?

[Genghis the Engineer]

A second GNSS receiver capable of using GLONASS and Galileo?

Does make you all rather reliant upon a single technology, although if it's demonstrably in different frequency ranges and using different satellites - perhaps.

As INS isn't accurate enough (by a LONG way) whilst I can absolutely see value in a second GNSS receiver, I'm inclined to think that we need a beacon based backup system. (Or more widespread availability of GCA I suppose - I'm pretty certain that none of us want to start making a habit of VDF !).

G

[Fl1ingfrog]

NDBs need to produce power dependent on the range required due to attenuation. As an enroute aid a lot of power was important but as a locator the power can be reduced and therefore causing less interference elsewhere. As the demand for radio frequencies increased the CAA required the power of locators to be turned down to quite a low power. The VDF indicator is a motorised unit and so signal strength is important to drive it. All the things that can cause interference also became increasingly difficult to manage: electrical storms, coastal effect, night effect, airframe static and last but not least the interference from one beacon to another. All these things always existed but were more manageable with the higher power. Dead reckoning was once the norm of course and enroute aids were just that, aids. The locator NDB was simply a cloud break aid that put you somewhere close to the place you wanted to be, the runway threshold. Plus or minus a few hundred metres being common and acceptable which is difficult to understand nowadays when a WAAS GPS will place you within 3 metres in two dimensions.

Perhaps a digital format for such a very simple pointing radio. A digital NDB enabling the receiver to discriminate between the wanted, the unwanted and noise. The ADF wouldn't need to be motorised either but rather a digital display with much improved sensitivity. I await to hear from those with radio engineering expertise. I'm very aware that I could be spouting nonsense regarding such an idea.

[Jan Olieslagers]

It's not nonsense you are spouting, at the contrary. It is so much common sense that even "the powers that be" thought along the same lines. They even managed to make something workable out of it, it is called "satellite navigation". (also known as "GPS" to those unaware of other satellite constellations, Glonass, Galileo, &c) :)

if that backup isn't NDB/ADF, what should it be
For en-route navigation, I always understood EASA intended a network of DME stations, whose data could/would/should be triangulated into location/heading/speed information just like one gets from GNSS. But I seem to remember this idea has been shelved, and am not aware of any alternative plan. Still less information about any plan B against GNSS failing on instrument approaches. But was there any plan B on any NDB approach if/when the NDB should fail?

[eglnyt]

In the UK at least the fallback for GNSS is intended to be twofold. a network of VOR/DME stations and a network of DME stations. The first is already in place, it's a subset of the original VOR/DME network, and is intended to support RNAV5. The latter is not yet in place, the UK has plenty of DMEs but they are concentrated in the South and not spread evenly across the country, but will support RNAV1. The limitation for most users is going to be suitable equipment in the aircraft. Multi constellation is likely to be much cheaper and more widely available, even my mobile phone can do that, than boxes which do DME/DME.

[Fl1ingfrog]

But was there any plan B on any NDB approach if/when the NDB should fail?

Yes there was Jan, it is called Very high frequency Direction Finding (VDF). The pilot transmits (VHF) requesting either a: QDM = magnetic track to the station, QDR = magnetic track from the station and QTE = true bearing from the station (usually used for chart plotting), triangulating bearings from a number of stations could be made. The VDF let down is when the pilot once over head from the series of QDMs turns onto an outbound track for a given time whilst descending and the track maintained/corrected by obtaining a series of QDRs, then turns inbound on a given timing, continuing to receive bearing from ATC (now QDMs) whilst descending to the procedure minimum height (MDH). This procedure was available for many years after the NDBs became in use so could be a backup. The military used QGH, the difference being that the controller calculated revised heading corrections from the pilot transmissions and also instructed the pilot when to descend in accordance with the procedure. VDF bearings for homing is still available from many ATC aerodrome stations.

The ADF was so named because it dispensed with the controller pilot interaction and therefore was considered 'automatic'. Both methods were usually available at a ATC aerodrome.

[Genghis the Engineer]

In the UK at least the fallback for GNSS is intended to be twofold. a network of VOR/DME stations and a network of DME stations. The first is already in place, it's a subset of the original VOR/DME network, and is intended to support RNAV5. The latter is not yet in place, the UK has plenty of DMEs but they are concentrated in the South and not spread evenly across the country, but will support RNAV1. The limitation for most users is going to be suitable equipment in the aircraft. Multi constellation is likely to be much cheaper and more widely available, even my mobile phone can do that, than boxes which do DME/DME.

For en-route navigation a VOR/DME network makes good sense (although most aeroplanes who need that capability probably carry perfectly adequate INS systems). But, for approaches, you're in a bit of a pot-luck there: if the VOR isn't within say 10 degrees of runway centreline and 10 miles, it's not a lot of use.

G

[Capn Bug Smasher]

I have fond memories of demonstrating an NDB approach / hold into the BBC longwave radio transmitter at Droitwich (I think... ?) for my IMC rating. You could just about get 198 longwave with 200 on the ADF :E I remember the controllers at Birmingham getting itchy as we hurtled around and around on the edge of their playground.

A summer or two before, I did a bit of work experience in light aircraft maintenance at Liverpool and one of the mechanics lamented the retirement of a colleague who could get the BBC on the aircraft radio while they worked on the ship. When that colleague left the knowledge left with him. I remember trying to work out how it was done. I was flummoxed until I did that IMC test... great stuff.

Hard to believe that was a decade ago, wow.

[excrab]

If you go back a couple more decades or so, to when I started teaching the IMC rating it was even easier, as the Droitwich frequency was 200 kHz which made it a really useful training aid for ADF tracking exercises. It was changed in 1988 to the current 198 kHz which made it harder with “modern” ADF receivers, as you could still get them to point at it but couldn’t really make out the speech so well so harder to “ident”....

[Big Pistons Forever]

The last NDB approach I did for real in IMC without some sort of GPS to provide final approach track guidance was in 1994. Using GPS even if it was “unofficially” always resulted in the flight path of the airplane being aligned with the runway, so I basically ignored the ADF needle.

The last use of the ADF went away when the good rock and roll stations went to FM or satellite. The NDB is 90 year old technology and is long overdue for the dustbin of old crappy nav aids like the radio range. Good riddance !

[ShyTorque]

Well at least it’s a slight improvement on Decca..... Thankfully that’s gone as far as my part of aviation is concerned. Using a system designed for a ship doing ten knots for IMC flight at 140 kts was ridiculous.

[Hot 'n' High]

....... In both cases I would have had real problems if I had tried to land using the NDB alone. ........

They are dreadful for SA as, in theory, they get you to a point where you expect to see a certain picture when you break out but, instead, it often spits you out (for the reasons you and others note) somewhere else. OK, not far off but, given you should then be able to land off it, sometimes that's far enough to be a pain to complete the line-up on final and a rapid judgement call is needed as whether it can be flown safely or you need to fly a MA. Snap decisions are never helpful at such times!

Re NDBs en-route, a lovely story of a friend who got his first Jet job on the 727 not that long after getting his IR. Trogging North back to the UK past Portugal as PNF, they got an en-route Hold thrown at them based on an NDB. A Training Captain was PF and so suggested that this would be a good chance for his P2 to demonstrate an NDB Hold. Friend staggered and lurched a few times round the Hold dragging his 100 or so pax along in loose formation behind him before, thankfully, onward Clearance came through and, with much relief he re-established, arrow-like, outbound en route.

With a feel of impending, career-limiting, doom, he handed back to the TC while rapidly considering (a) how up to date his CV was and, (b), if he knew of any leads going in other airlines (any would do!) as he felt sure he was about to be hung out to dry by the TC. The TC turned to him after a short, but ominous, pause and said "Mmmmm, not bad, not bad ....... all I can say is ................ thank God you flew that - I wouldn't have known where to start! I just thought you, having just done your IR, would be best placed to fly that! Very well done!!!!!".

Sums NDB's up really!!!! :)

[Genghis the Engineer]

With a feel of impending, career-limiting, doom, he handed back to the TC while rapidly considering (a) how up to date his CV was and, (b), if he knew of any leads going in other airlines (any would do!) as he felt sure he was about to be hung out to dry by the TC. The TC turned to him after a short, but ominous, pause and said "Mmmmm, not bad, not bad ....... all I can say is ................ thank God you flew that - I wouldn't have known where to start! I just thought you, having just done your IR, would be best placed to fly that! Very well done!!!!!".

Reminds me of taking my instructor initial skill test out of a somewhat unfamiliar airfield. Five minutes after take-off I realised that I had lost positional awareness. So I turned to my examiner, who was pretending to be my student at that point "So Bloggs, can you tell me where we are right now?", he went into a textbook description of nearby roads and towns and told me exactly where I was, "Well done Bloggs, now onto the first exercise"....

G

[Hot 'n' High]

Reminds me of taking my instructor initial skill test out of a somewhat unfamiliar airfield. Five minutes after take-off I realised that I had lost positional awareness. So I turned to my examiner, who was pretending to be my student at that point "So Bloggs, can you tell me where we are right now?", he went into a textbook description of nearby roads and towns and told me exactly where I was, "Well done Bloggs, now onto the first exercise"....

G

That, G t E, as a fellow Instructor (now lapsed) is quick-witted style!!! Absolutely love it!!!! :ok:

My CPL GFT also took place from an "unfamiliar airfield". I rang the Examiner, as briefed if he had been delayed and not got in by a certain time, to get the route from him. But that revealed a small snagette.

I was booked into the Flypro to fly the GFT from airfield "A". The route he gave me started at airfield "B" some 70+ miles away and which I'd never even been near let alone to. But that was where he was waiting for me to pitch up, complete with an A/C, to do my Planning followed by the Flight!

The reason I'd never been there is mainly as it was behind a wall of impenetrable CAS ...... policed by fire-breathing ATCOs with an endless supply of MOR forms ..... and which was renowned as "Infringement City" - so the very careful dog-leg required added maybe 20+ miles to the above! No pressure there then!!!

The Ops guys at "A" did a great job springing my A/C early so I could fly at Vne (+ some!) to where my Examiner was waiting. Fortunately, I arrived in time to do my second Route Plan of the day and it all worked out OK .... the ATCO-dragons had continued to sleep soundly as I whizzed past their lair! But I was rather relieved the Examiner didn't ask for the paperwork to do with the first flight tho! :}

Happy daze!!!! H 'n' H

[jmmoric]

The NDB is 90 year old technology and is long overdue for the dustbin of old crappy nav aids like the radio range. Good riddance !

The ILS is close to being 90 years old technology as well, and so is the internal cumbustion engine, and fire is even older?

But yes, there are better alternatives now.... until the Kessler Syndrome hits us at least...

[Hot 'n' High]

The ILS is close to being 90 years old technology as well, and so is the internal cumbustion engine, and fire is even older?.........

But the difference is, in the cases cited above, they all worked as advertised rather than being at the whim of the weather and other gods!!!! Flying NDB approaches in good vis on checks was both amusing .... and sobering! Using GPS as a backup to the NDB worked quite well tho!!! :ok:

Seriously tho, you are correct re ILS. What intrigues me is was MLS used much/at all? Seems they had MLS at LHR up until 2017. The Mil have used MLS quite a bit but not sure what civvie uptake there was. I never came across it outside the Mil. I guess, if only a few airlines equiped their aircraft with it (I think BA equiped some of their SH Fleets with it), then the benefits of MLS would have been negated as, particularly at busy fields with a queue down the ILS, you'd have a mix of MLS and ILS traffic so would have to go for the lowest common denominator (ILS) to make sequencing easier. I guess it would be harder to utilise the benefits promised by the MLS on mixed ILS/MLS arrivals - if that were even possible. Dunno!

[eckhard]

We had MLS on the BA Airbus fleet and it was a total waste of money. It worked perfectly but, as you said, we were never able to take advantage of the benefits of reduced spacing because we were never allocated a discrete runway and therefore had to share with ILS traffic.

[Hot 'n' High]

We had MLS on the BA Airbus fleet and it was a total waste of money. It worked perfectly but, as you said, we were never able to take advantage of the benefits of reduced spacing because we were never allocated a discrete runway and therefore had to share with ILS traffic.

Cheers eckhard, suspected that was the case. I think GPS reared it's head just as MLS was starting to gain traction. Anyway, thanks for the confirmation. Cheers, H 'n' H