NDB approach - GPS may be used in-lieu of NDB, using NDB waypoint ?.

[Lefthanded_Rock_Thrower]

NDB approach - GPS may be used in-lieu of NDB, using NDB waypoint ?, has this been considered by ze gestapo ?.

With the new super dooper TSO GPS and EFIS systems on the market do you think it would be plausable ?.

Pro's and cons ?, I have not seen it annotated on a plate yet, has anyone ?.

[ravan]

Nice idea .........but not yet legal:(

Practically speaking though, I don't think I have flown an NDB into Archerfield in anger without having the Garmin set up on the AF NDB since I was shown how by an ATO during a renewal a couple of years ago.

Bloody brilliant way to fly an NDB using the GPS external CDI just like a VOR...way more accurate and don't know about anyone else but suits the way I think much better.:ok:

[haughtney1]

I now fly the most accurate NDB approaches I've ever done using the GPS for guidance, and the NDB displayed to "confirm" that the 3 GPS systems + 3 INS systems know where they are:}
Perfectly legal in this part of the world (Europe) where they are a generation behind in the thinking of GPS derived approaches......
Bearing that in mind, as long as you display (monitor) the NDB needle to validate your course/position, I would assume there is nothing wrong with it.

I should also add that even our EFB has an aeroplane symbol on it that allows you to fly an NDB approach!

Then again, it has been known for me to speak out of my bottom... :E

[27/09]

No reason why you can't back up the ADF pointer with a bearing pointer on the EFIS selected to the GPS using the NDB as the waypoint.

[Feather #3]

Overlay approaches were discarded here in favour of a runway approach with a profile.

The overlay is used in the USA for VOR [and NDB where/if they exist] with minimal cost to the user as it's simply another use for the same [previously surveyed] chart.

The Oz concept was designed to be safer with lower minma.......now, let the debate on the distance measurement vs spacial orientation begin!!:rolleyes:

G'day ;)

PS you're mad if you don't have the gps backing up the ndb, and of course, quite usable as a DME substitute where specified!:)

[alphacentauri]

It's been done in PNG, because the locals where ripping up the power cables to the NAVAIDS. Least expensive solution was to replace all NAVAIDS with a GPS waypoint and authorise "GPS may be used in-lieu of NDB, using NDB waypoint"

Pretty sure there was NOTAM issued by the PNG authorities about 2 years ago, not sure of the current status.

I also know there were issues in Timor a few years ago with NDB's going out of commission and therefore being no approach available...similar solution was implemented by certain ADF assets in the area.

I think the concern might be that by doing this it becomes more a psuedo NDB/DME approach, rather than a pure NDB approach with timed legs or allowances for different cats of aircraft. Also think there might be a gps nav performance issue....but can't be 100% on that one.

Still, I reckon its got to be more accurate than tracking a steam driven gauge over mountainous terrain or coastal areas....I think if implemented properly it could work.

[ForkTailedDrKiller]

Yet another example of the lethargy of those responsible for aviation in this country!

Why would anyone bother chasing the needle around when they have a functioning TSO's GPS on board! Coupled to the AP - all the better.

I can see nothing in the rules that precludes anyone from flying an NDB approach with reference to the on-board ADF indicator as required - but using the on-board TSO'd GPS and AP to steer the aircraft on the required tracks. If the GPS is TSO 146a, you will be tracking +/- 1.25 meters - should be well within the required tolerances!

Probably academic anyway cause the only reason I would be flying an NDB approach would be if the GPS had crapped itself!

Dr :8

[stillnoeyedear]

Have always done it during CIR check flights. As long as you meet the obligations of referancing the ADF needle and monitoring the aid, one can complete the approach fully coupled if your fit can do it.

You'll find most ATO's have entered the 20th century (not quiet the 21st yet), but some insist that it's done without another referance - something about a skills exercise...

SNED

[Wally Mk2]

...............but some insist that it's done without another referance - something about a skills exercise...
This is true 'stillnoeyedear' (like that nic:ok:). I reckon the NDB should be flown under test conditons to prove that it can be performed as it should be without the use of the GPS. Obviously in actual conditions on ones own for Eg. the use of the GPS should be encouraged to suppliment the NDB App.
If nothing else the GPS is good for distance from the aid whilst conducting the NDB App if for no other reason than to advise somebody who might be asking how far Nth are you for Eg. Also excellent for the shortening/increasing of outbound legs due wind.
Overall USE what you have at yr disposal, & in yr case Dr:8 you do remeber what an ADF needle is right?:}


Wmk2

[neville_nobody]

I agree for IR renewal it should be aid only, as GPS can (and do) fail.

However it is perfectly legal (not to mention easier and less stressful) to set up your GPS in a omni mode and fly the NDB approach as you would a VOR approach on your HSI. As long as the NDB ident is going and you don't go outside of the 5 degree tolerance on the ADF that is perfectly legal.

I know on some PC12's this is the preferred method as the ADF get's some shielding during turns on approaches.

[Fred Gassit]

What happens (or is supposed to happen) when you get a disagreement between the ADF needle and the GPS course? I've seen this many times with the needle well out of tolerance and the GPS saying its all good.

[waren9]

Sit on your hands and wait for the needle to lose interest in the passing CB and get back pointing at the aid.

Of course if you're lucky enough to have an FMS driven by 3 IRS and 2 GPS with RAIM and FDE then its not doing any radio position updating anyway. You're simply following a line in the FMS database. Carry on as normal. Except on check day.

Not a worry in the sim, as ADF needles never wander. They either work or they dont.:ok:

[ForkTailedDrKiller]

in yr case Drhttp://static.pprune.org/images/smilies/nerd.gif you do remeber what an ADF needle is right?http://static.pprune.org/images/smilies/badteeth.gif

Sure do Wally! I fly my mandatory 4 per year for currency and CIR renewal, and I have actually flown at least one to the minima for real - into Kidston, about 15 years ago!

..... but when the ADF in the FTDK goes kaput it will be replaced by second TSO146a GPS.

Dr :8

PS: I also remember DME homings and let-downs!

[who_cares]

Cant see why you would want to do a circling approach using GPS, why not just do the gnss approach. Straight-in constant descent flight path Ill take that one anyday.

[Lefthanded_Rock_Thrower]

Not every Aerodrome has an RNAV Approach.

[who_cares]

Very true.

Cant be too many airfields left with just a NDB approach theses days..?

[neville_nobody]

True, however not all IFR GPS setups are approved for RNAV Approaches. Neither is every pilot. All it means is that you can take the stress out of NDB approach.

What happens (or is supposed to happen) when you get a disagreement between the ADF needle and the GPS course? I've seen this many times with the needle well out of tolerance and the GPS saying its all good.

Legally you would have to follow the ADF unless you have a setup that allows you to fly the NDB approach on the GPS as primary means.

[flyboy2]

When flying in Africa, very few navaids remain serviceable for long due to theft, so using GPS has been most useful.

[Lasiorhinus]

It makes me wonder, why not set up your TSO'd GPS in a moving map mode, establish yourself over the ocean, set an accurate QNH, and just let down until you see waves? :E

Then just trundle on over to your airport visually.

Blimey - we should all be doing that! And to think we've been flying instrument approaches, instead!:E

[NOtimTAMs]

I agree that in lighties given the choice and time a straight in GNSS RNAV APCH with a TSO 146a GPS unit is tops in the absence of an ILS.

BUT let's say you've had advice (perhaps even from NAIPS!) that the cloud base is higher than the 10NM MSA and you plan to descend to MSA on track trusting you'll either get clear sooner or later (up to the point of circle to land from over the field if visual at the MSA by then). Blackall is a good example: 10NM MSA is 2400'. If you don't get clear (b@gger!) then you have a choice of either chugging out to the start of the the GNSS RNAV APCH (a total of 20+ NM at 2700') or continuing over the top of the aid and chugging around a 6 minute total (out 2 1/2, turn 1, in 2 1/2 minutes - if you don't have to enter via the hold - another 3-4 min) NDB APCH with the supplementary assistance of your trusty TSO'ed GPS.... Ballarat and Ballina (stuck in the B's!) are another couple of places (amongst quite a few others that don't have GPS arrivals) where it can be useful.

Of course, places like Georgetown and Point Cook only have an NDB APCH....

I too don't understand why the NDB approaches can't be flown with an appropriately TSO'ed GPS. I've seen more ADF units and NDBs go Tango Uniform than GPS systems ...