NDB lament.

[AdamFrisch]

I trained on steam gauges (there was nothing else then) and have just recently gotten a little more used to GPS. The 12.000hr (I kid you not) rental 152 I fly out of Lydd is all old school - not a GPS in sight. It barely has a VOR.

I don't mind this at all, but one of the things I always used regularly on aimless flights was the ADF, just as a little pointer and guide to where you were so you don't have to be buried in the chart all the time. I like ADF - it's simple and useful. But these days, they're on the chart, you tune them, but rarely do they work.

Is there some kind of list of when and which NDB's they plan to shut down in the near future? And how long before they'll all be gone?

[IO540]

NDBs work as they always did - assuming you have a working ADF which is not a common feature of rental wreckage.

They are just not that good when there are terrain assymetries about; coasts, hills, etc. The Lydd NDB is a joke... one can fly a perfect straight-in approach (GPS/autopilot coupled) and watch the ADF needle on the RMI go all over the place.

[AdamFrisch]

Maybe the ADF is crap in the aircraft, but I seem to miss more than I hit, even when I'm real close. I seem to remember that many had been shut down - the ones at Gatwick, for instance. The one near Headcorn (or is it Rochester? - I don't have my chart handy) never tunes, even real close.

[Big Pistons Forever]

Proper use of the ADF

1) Select NDB as waypoint on GPS

2) Enter desired track to waypoint

3) Fly the little white airplane up the magenta track

4) Tune ADF to 60's Rock and Roll station

5) Enjoy better flying through high technology and the last decade of good music

Really with used portable GPS units available for the same price as a good headset, I do not understand why pilots deprive themselves of the most accurate positional and navigational information available (backed up with a map of course).

[BackPacker]

If the NDB is on the (current!) map and/or in the AIP, and is not Notamed to be U/S or withdrawn, then it should be working. Otherwise it's a flight safety issue and you should not post about it on this forum, but write to the CAA about it.

But I have to agree that strange things happen sometimes. There's a DME "FRT" in the Netherlands (co-located with the RR NDB) which hasn't been printed on the "official" ICAO map for years now. But it is on the Jeppesen VFR map, it's also in the AIP and when we tried to use it a while ago, it worked just fine. It's also not part of any SID or STAR. A real mystery DME that only Jeppesen seems to know about.

[IO540]

Jeppesen "know" about a number of NDBs

I think it's because in N Europe there isn't a great shortage of nationally produced VFR charts, so not many people buy the Jepp ones, so mistakes do not get reported to Jepp.

It's like the old Bottlang VFR touring guides. They were full of mistakes.

[GARDENER]

Don't forget NDB's DOC vary from one station to another, GPS is great but take a scenario such as this for example. Azores perhaps, locator approach, no GPS approach published or no RAIM for whatever reason....it soon becomes a very useful aid! Obviously backed up with whatever you can get a signal from!

[IO540]

Obviously backed up with whatever you can get a signal from!

Yes, a GPS

Obviously one would fly an NDB approach using the GPS OBS mode.

[FlyingOfficerKite]

We seem to be in a technological no man's land in some respects. ADF/NDB systems that are approved but are unreliable and GPS systems which are reliable but unapproved!

Surely this can't be the old worry that someone might degrade GPS or switch it off!?

I know it would be expensive to change over to modern systems but its going to happen one day and the benefits are already in evidence.

KR

FOK

[Sir Niall Dementia]

IO540;

I think what Gardener is referring to is the abysmal GPS coverage at the Azores.

It can get so bad there that the NDB is the only reliable aid, GPS is often either RAIM unavailable or "GPS signal was lost ..... seconds ago"

I heard a rumour last week that all en-route NDBs and VORs will be phased out by 2018. (Note the word RUMOUR in that last sentence)

[Ultranomad]

GPS systems which are reliable but unapproved

Reliability of GPS is often overestimated. With the solar activity on the rise, many specialists predict more frequent loss of GPS reception in the coming years, and loss of reception due to aurora borealis is a fact. I am not trying to assert that ADF is any better, but relying on GPS alone does not look like good airmanship to me. Personally, I wouln't want to fly over the North Atlantic without a non-GPS backup to GPS - e.g. Loran (for lack of an affordable INS).

[IO540]

I think what Gardener is referring to is the abysmal GPS coverage at the Azores.

It can get so bad there that the NDB is the only reliable aid, GPS is often either RAIM unavailable or "GPS signal was lost ..... seconds ago"

Surely not. The GPS sats orbit around the earth. They don't have a favourite place

[Sir Niall Dementia]

IO540;

Sorry, from personal experience the coverage there really is less than adequate. Then again so are the SAR procedures and a host of other things, but the GPS signal is about the worst.

SND

[englishal]

I think what Gardener is referring to is the abysmal GPS coverage at the Azores.

Impossible..The satellite constellation orbits the earth at 12000km and so are always changing location and so there is no way that one place can have "abysmal GPS coverage"....You may get the very odd occurrence when the geometry of the satellites may be bad (Hence Dilution of precision - DOP, for example PDOP and HDOP) - perhaps one has gone down for example, but there are so many now (30 something?) that even if this did occur then it would only be for a brief time (order of minutes) and you should still get 3D nav accurate to 100m. The great thing is that the GPS receiver tells you this too! UNlike an NDB which the only way to work out when it is not working is to keep indenting it all the time.

[Ultranomad]

Impossible..The satellite constellation orbits the earth at 12000km and so are always changing location and so there is no way that one place can have "abysmal GPS coverage"...

...unless you have an ionospheric anomaly over this particular location. Such anomalies are more frequent at high latitudes but in principle may occur anywhere.

[englishal]

I have just been to Eurocontrol's RAIM prediction website and there are currently 10 satellites visible from the Azores. Also did a RAIM check for Santa Maria Airport on the Azores and there are no RAIM outages.

Atmospherics could explain it, but I doubt it. I have worked in the Barrents Sea, and even during really strong solar flares and Northern Lights everywhere I have only ever seen the GPS drop out for a second or two....

GPS fitting and antenna location are more likely to play a role in these outages....

[AdamFrisch]

My questions is much more sinister: how does the GPS satellite know where it is?

[GARDENER]

Apologies, my point was more that in the Azores many of the procedures are Locator or NDB which is why I used that example, not necessarily you will have more problems there. I agree with englishal that much comes down to "fittings".

I0540 Yep! I would back it up with GPS if available, if the kit is available then use it....we also have the added benefit on some occassions of the Flight Inspectors equipment down the back for a 3rd opinion!

[Black Prince]

Sir Niall....

"I heard a rumour last week that all en-route NDBs and VORs will be phased out by 2018. (Note the word RUMOUR in that last sentence)"

It's no rumour, see details here.....

http://www.ukfsc.co.uk/files/Consult...Aug%202009.pdf

Not all VORs affected, but most NDBs.

[JOE-FBS]

Am I correct in understanding that the GPS satellites can be moved around to suit the requirements of the people who own them i.e. the US military? So if they have operations somewhere they may move the satellites to improve coverage there and potentially leave other areas uncovered?
I remember many years ago when the RAF attack squadrons first got Tornado one of the navigators saying he still carried a map because you'd feel a fool without one when all the kit failed. With that attitude in mind I flew a one hour VFR nav' in Southern England last week using VOR, DME, NDB, looking outside with the map and with the GPS on just in case. Then again, I'm not a sky god so like the reassurance