Non precision MDA/DA
 

Hello Forum,

sorry, but did I miss something the last few month?
I was always the opinion that Non Prec. Apps (talking of NDB now) are MDA based.

Means that I have an altitude which I will not bust.
Bombardier tells you to add 50 to the MDA and call it a DA and perform a GA if you haven't seen the light until then.

But no matter what the Bomabrider procedure is,... have a look to LOWL or LOWS. Check the NDB APPs.

They post a DA there.
Why? What would you do? To be on the save side, as long as I do not know why there is no MDA, I will still add 50 ft and perform GA there. But seems strange for me. If you read strictly the paper you can bust the DAs on those Non Prec. Apps. :confused:

What's you opinion?

Thanks for you help.

Check the side of the plate. It probably says PANS-OPS 5.
PANS-OPS 5 now caters for constant angle non precision approaches.
If it says DA on the chart, use it as an DA. The loss of xx ft after initiation of the G/A has now been taken into account. There are not many procedures which are PANS-OPS 5 now (Europe) so the MDA+50ft is not completely a thing of the past.

Regards

Its 30' where I work.

The idea is that, lets say MDA is 400', you add your 50' so that gives you 450'.

You do the approach and at 450' you see nothing.

You start to go around but the a/c is still descending.

As you started the GA 50' above MDA, even though it takes a moment or two to arrest your descent, and you lose a bit of height as you do so, you don't go below MDA.

Whereas if you started the GA at MDA, you surely would.

Now, back in the day, you'd level at MDA and then clatter on until you reached the MAP or saw the runway. The so called 'Dive and Drive', so no need for extra height.

Perfectly good, IMHO, but far far too dangerous.:hmm:

Challey - some good stuff here http://www.pprune.org/tech-log/401043-mda-constant-descent-npa.html.

BBF - try not to tread on any squeaky floorboards outside the bedroom or we will have to hear again how great the ?Fokker Tri-motor was it? at 'dive and drive'.:)

BOAC, now I wonder who you are referring to?

@Ken

Thanks, of course that is what the approaches are all about. But check the plates. You will find NDB Apprs with a DA not MDA.

@Open Des
Thanks that was the right answer :ok: found Pan OPS and changed issues on the new plate are minimums an descent angles.

@BOAC
Thanks BOAC thats a good link.

All of you thanks for support.

Cheers

Chally

BOAC

Fokker tri-motor????:confused:

Am I getting old?

(it was when I was on the Shed. ;))

Chally 604.

Re minimums. While you and I all do the old stabilised app stuff,CANPA or whatever it's called.

If you were a dive and drive operator you'd want the 'proper' MDA would you not?

Not everyone has bought the CANPA stuff and non precision apps are as old as it gets in aviation these days.:)

Normally on these PANS-OPS5 approaches you cannot 'dive and drive' as terrain separation is based on the published descent angle.
CANPA is not much harder on a old-fashioned aircraft. ALT vs. DME using V/S will do the trick just fine.

Regards

Yeah sure. I like it. If you want it basic, HDG + V/S is perfect and works always fine. Adjust your V/S by the altitude deviation at a certain mileage times two and you fly this thing like an ILS. :ok:

Take care

Chally

Flying it like an ILS is done by simply pressing the approach button, even the usual presentation to the pilots nowadays is exactly like an ILS :)

But yup, it is sometimes good training doing it the old fashioned way with HDG and V/S using the altitude/dme table on the approach chart.

BOAC, now I wonder who you are referring to?

C'mon, now, chaps, let's be nice ...

Chally

If you are working for a European operator, then EU-OPS 1.430(d)2 says ...
So an NPA flown under these rules is effectively an approach to a DA.
Perhaps some states/airports publish minima including the increment for GA transition, perhaps your Bombardier reference has adopted the terminology; but your company should specify whether to add (50ft) to any NPA minima or not.

Not Fokker, Lockheed.
Nevertheless, we still do a variation of dive and drive...and it seems to work quite nicely...for us, anyway.
I would suggest that dive and drive is not for everyone...only for those that do so regularly...and quite safely, thank you.:)

Correct, as long as you drive a C 411....

BOAC
Took three days - need stronger bait...

Much stronger.:}

411A, for those of us who have been around longer than a week or two, has shown that he is made of much stronger stuff than would see a man tremble in the face of a bit of incoming ...

Fact is, most of the 'pilots' around here seem to know little about flying! Scares the hell out me! I sure hope I won't be learning from some of you guys one day :eek:

Luckily there is always 411A to save the day and remind you of how to fly the thing :cool:

411A is the man! :D

Flying 100-200ft below the exact 3° profile on an NPA makes a lot of sense (provided the limiting steps allow). You can actually get to the MDA, level off (drive, shock horror), get visual and land, as opposed descending nicely down the precise 3° slope, to getting to the MDA during the level-out but not being able to land because you're now above the PAPI. It's called wriggle room. :ok:

Bloggs,

The idea is that you DON'T level off! You continue your stabilised approach if you have the required visual references at MDA/DA or you initiate a go-around. There's no mucking around below the profile: you wouldn't do it on a precision approach so why do it on a NPA?