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TNCM VOR Y 10 - CDFA or Non CDFA ?

Hi everyone,

Just a question about a VOR approach in TNCM (Saint Maarten)

As you can see, there is no FAF, and the minimums section of the plate mention « CDFA ».
I agree that we can fly this approach with CDFA technique but only if we have a GPS, which is not required for this approach.

So my question is : can we fly this approach using a non CFDA (dive and drive) technique as shown by the thick line on the approach profile view.
And if yes, what should be the minimums ? And why did they put only « CDFA » on the minimums section ?

Thanks a lot for your help

France

Isn’t current practice in Part.CAT all non precision approaches are CDFA with go around initiated at minima? A 1,555 foot hill at the end of the runway might want you to think again about dive and drive?

A swept wing transport in landing configuration is not exactly poised to go around from a dive and drive.

Oxford (EGTK)

I agree,

But in that case, why the thick line on the approach profil view doesn’t show a CDFA ?

Last Edited by MxLt at 10 Jun 18:21
France

How would you fly this approach without a GPS?

France

@MxLt your base turn is based on 3 minutes outbound, so approximately 5 to 6nm. Not sure what radio NAV identifies FF10, but if you started your CDFA on completing the base turn, your DA is around 3 nm from the threshold, well beyond the 1500m visibility minima.

Oxford (EGTK)

Thanks for your reply !

But I don’t understand why the thick line on profile view shows a « non CDFA » technique…

France

This is a VOR approach – so no GPS required or can be expected when designing the approach.
Therefore the only fix that is available is PJM VOR. Therefore the last point that you can actually identify (w/o gps) is the end of the base turn (I’m not sure if that point can legally used when designing the approach).
As Robert already wrote: Starting a descent at end of base turn is never a CDFA as the design limit for a CDFA is that the angle of descent should not be less than 2.75°. So the think line can not be a CDFA.

If you have a GPS, you can use the FF10 fix and start a 3deg CDFA from there.

Germany

This is an approach without a FAF. As originally charted, it can’t be flown CDFA as you don’t have a FAF. The end of the inbound turn isn’t good enough as you can’t be certain of your distance from the VOR.

In their navigator databases, Jeppesen have added a FAF – FF10 – and using that you can fly a CDFA. This is perfectly legal as there are no restrictions on the vertical profile on final approach. (Except, of course, that you can’t descent below minima unless visual.)

ESKC (Uppsala/Sundbro), Sweden

Thanks a lot !

So if I well understood, I can fly this approach as NON CDFA. After completed the base turn, I start descent down to MDA and wait until I have visual.

But what minimums should I take ? The approach plate mentions the minimums only for CDFA… and we are flying non CDFA…

Thanks

France

AFAIK, CFDA & non-CFDA minima are the same, it’s the same MDH, for both up to you to make sure that you don’t go bellow MDH on MAP: some will suggest you add 50ft, 10% of your ROD…

To be on the safe side, I tend to add 300ft if air is vey turbulent & instruments are sluggish with my sloppy flying

Last Edited by Ibra at 10 Jun 21:34
Paris/Essex, United Kingdom
18 Posts
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