Visual Descend Point

[MD80rookie]

The FAA developed this procedure, for non-precision approaches. Haven't really understood the meaning of it, but my question is have any of you JAA-trained guys come across this in any european operator?

[Starbear]

The idea behind a VDP lies in the fact that on many Non Precision approaches the MAP (Missed Approach Point) could often be at the fix used for the approach, which could be located before the OR beyond the RW or it could even be the RW threshold itself. Plus numerous other variations.

So if level at MDA (MDH) and one does not become visual until say just before the MAP then clearly a safe landing may not always be possible ( given MDA/MDH will nearly always be higher than ILS Cat 1).

It is then practical to either calculate or use a published VDP (which for simplicity's sake can be pictured as the point where MDA/MDH intercepts a 3 deg path to RW threshold. If one is not visual by then, there is little point in continuing the approach even though not yet at the MAP except perhaps to establish the likelihood of being visual for subsequent attempt. ( not forgetting that even if executing G/A earlier one must continue to MAP before any turn is executed)

Europeans have for many years flown a continuous descent approach and making a Land/GA decision at MDA and not the MAP. Much more stable and safer approach with greater opportunity of safe landing.

I am not aware of any European approaches which have a published VDP but given that this is only an advisory ( similar to Alt/DME tables on charts) it could be down to the chart provider.

Bit lengthy but hope it is of some use.

[Intruder]

The FAA appears to have made the VDP regulatory via the AIM (p. 5-4-18):
The VDP is a defined point on the final approach course of a nonprecision straight-in approach procedure from which normal descent from the MDA to the runway touchdown point may be commenced, provided visual reference required by 14 CFR Section 91.175(c)(3) is established.
. . .
The pilot should not descend below the MDA prior to reaching the VDP and acquiring the necessary visual reference.
While some may not consider the AIM as regulatory, arguing that point to an investigatory board will likely yield you nothing...

[Starbear]

Fair point Intruder.

[Capn Bloggs]

Everybody should be doing Straight-in NPAs via a 3° descent these days unless you don't have a DME or GNSS distance, in which case a VDP is irrelevant anyway. The yanks should get alt/distance tables on their charts pronto. :=

The pilot should not descend below the MDA prior to reaching the VDP and acquiring the necessary visual reference.
Glad somebody thinks that's a good idea... :cool: