Question about NACO Approach Chart Profile View

5 Answers

1. Best Answer
   
   

   
   

   John D Collins on Oct 01, 2016

   The V symbol at VWV 2.2 DME is a Visual Descent Point. You can search on the current version of the AIM for the search term “Visual Descent Point” and read all about its significance and usage.

   +1 Votes 1 Votes  0 Votes

2. 
   

   
   

   murphypete on Oct 01, 2016

   Ah, OK.

   From FAA publication, Descent to MDA or DH and Beyond – P-8740-09:

   “The Visual Descent Point (VDP) is a defined point on a straight-in, non-precision approach from which you can descend below the MDA, as long as you have the required visual reference. If a VDP is available, it will be indicated by a “v” on the profile view portion of the instrument approach procedure chart. Do not descend below MDA before reaching the VDP.”

   So, even if you have met all the other criteria for descent below the MDA, (having the appropriate visual references in sight, etc.), go no lower than MDA until you reach the VDP.

   Thanks! Very helpful!

   0 Votes 0 Votes  0 Votes

3. 
   

   
   

   Mark Kolber on Oct 03, 2016

   Not quite. You certainly can go lower than the MDA before the VDP if you have the required visual references. That’s not the problem it’s designed for. The problem is the exact opposite.

   The VDP is advisory. It is telling you at what point you can make a more or less 3 degree approach to the runway. In a 172 using a 90 KIAS approach speed, that’s about a 450 FPM descent rate. There should be no problem breaking out visually miles early and deciding to use a leisurely 100 FPM descent rate until in position for landing. You probably did that regularly on VFR straight in landings.

   The problem is that the MAP on a number of IAPs is too close to the runway to allow for a normal descent if you first break out there. Some are at the threshold itself and would require you to drop vertically like a helicopter. The regs tell you you need to use normal maneuvering to get to the runway from the MDA. Folks can argue “normal” but I doubt it means a 1500 FPM descent from 800 AGL!

   The VDP is advising you the closest in that you can get that 3 degree descent and that any closer and you will need to increase your descent angle.

   +1 Votes 1 Votes  0 Votes

4. 
   

   
   

   Bill Zaleski on Oct 03, 2016

   The AIM states that descents should be made NO SOONER than reaching the VDP. The recommendation as read from the AIM says nothing about descending AFTER the VDP and does not suggest that a descent should not, or could not, be made after the VDP; in fact it’s just the opposite, descents should only be made at or after the VDP. Just because an approach glide-slope might exceed 3˚, it doesn’t mean a stable approach can not be made. Accordingly, many approaches in the US have glide slopes greater than 3˚ in which stable approaches are made.

   Going below the MDA prior to VDP will get you a bust from a DPE. He has no latitude in this situation. Not a healthy thing to do.

   0 Votes 0 Votes  0 Votes

5. 
   

   
   

   Mark Kolber on Oct 06, 2016

   I won’t comment on the standard checkride vs real life issue.

   I agree with Bill on the importance of the VDP in the sense that waiting until the VDP (and not much after that) and following a standard descent profile provides a level of obstacle clearance. Given the vagaries of low weather, visibility, terrain, obstructions, and assorted visual illusions, the wise pilot is going to take full advantage of a VDP when there is one available.

   But “unhealthy” to descend below a 800′ MDA before the VDP when one breaks out at 1200 and there is 100 daytime miles visibility below the ceiling?

   0 Votes 0 Votes  0 Votes