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Pin Head
29th May 2016, 03:57
Hi

Never used it or hear of it. Bit confused by the Boeing FCTM definition. Please can someone help me.

Non precision approach, the point of transition to visual reference based on arriving at MDA.

Thank you

pattern_is_full
29th May 2016, 05:30
It is an FAA-U.S. thing.

It is the point where, descending to, or level at, MDA, you would intercept a hypothetical ~3° glide slope (since it is for non-precision approaches, there is no "real" glide slope to track.)

Marked on plates with a heavy bold V symbol.

http://images.slideplayer.com/14/4330538/slides/slide_57.jpg

Basic idea is to avoid pilots flying to the MAP and getting "visual" with the runway environment at the last moment and making a steep descent. The VDP will normally be reached before the MAP.

eckhard
29th May 2016, 05:37
From the FAA Pilot-Controller Glossary:

VISUAL DESCENT POINT 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 the approach threshold of that runway, or approach lights, or other markings identifiable with the approach end of that runway are clearly visible to the pilot.

I think the VDP concept was more relevant to the old 'dive and drive' NPA technique. After you levelled at the MDA, the VDP was a useful guide to where you should restart your descent. If you were still level after the VDP, you were probably too high to make a normal landing.

With the general acceptance of CDFA techniques, the VDP is perhaps not so useful anymore, except for special cases where the CDFA may not be appropriate.

john_tullamarine
29th May 2016, 09:06
Even if such a thing were not included on the plate, would not a sensible pilot have worked out precisely what windows pertain to the safe conduct of the approach .. ?

eckhard
29th May 2016, 10:02
Even if such a thing were not included on the plate, would not a sensible pilot have worked out precisely what windows pertain to the safe conduct of the approach .. ?

Yes, but unfortunately one man's sensible windows may be another's deviation from strict SOP, so I suppose a helpful reminder actually printed on the chart may be helpful to some.

de facto
29th May 2016, 11:55
VDP??never heard of it?? Its been in the fctm since eveeeeeeeer.
Man,you are really worrying.

john_tullamarine
30th May 2016, 00:21
may be another's deviation from strict SOP


Long, long time ago at the line check debrief, a much older and much wiser check pilot observed to me something along the lines of "the front page of the manual really should have words to the effect of 'to be read with a bit of intelligent thinking and commonsense'".


That operator was keen on SOP .. but tolerated deviation provided there was a good and sensible reason at the time for such deviation ..

Intruder
30th May 2016, 01:35
Our manuals used to have a phrase to that effect, but it appears the lawyers and beancounters have forced its removal.

Oops! Still buried in the back of the QRH:In all situations, the captain must assess the situations and use good judgment to determine the safest course of action

+TSRA
31st May 2016, 00:50
In all situations, the captain must assess the situations and use good judgment to determine the safest course of action

Oooo...Dangerous thoughts, dangerous thoughts. I mean, who do we think we are asking those beancounters if we can think? Professionals? :}