Is Vdp regulatory if published?

[tataki]

thank you

 

[AC560]

Strictly speaking no but

91.175(c)
(1) The aircraft is continuously in a position from which a descent to a landing on the intended runway can be made at a normal rate of descent using normal maneuvers, and for operations conducted under part 121 or part 135 unless that descent rate will allow touchdown to occur within the touchdown zone of the runway of intended landing;

 

[DC8 Flyer]

If you have the ability to ID the VDP "point" it is, ie DME, GPS, cross radial (if such a thing exists), etc.

 

[Doc Holiday]

No, except for 121 ops.

121.651 (c) (4) explains the exceptions.

 

[JECKEL]

(VDPs) (current Sec. 91.116). VDPs are not an integral part of the approach procedure. An aircraft that is not equipped to identify a VDP has the same approach minima as similar aircraft that is equipped to identify the VDP.
Mandatory use of VDPs is considered inappropriate for a number of reasons:
(1) VDPs that use Distance Measuring Equipment (DME) fixes may, because of displacement factors and/or fix errors, result in descent angles that are either too shallow or too steep for the approach.
(2) A mandatory VDP rule discourages the purchase and use of the very equipment necessary to identify the VDP. This is so because compliance can only be required of those aircraft that are equipped to identify the VDP. For these reasons, the final rule, like the NPRM, does not include a mandatory VDP requirement.

f. Visual Descent Points (VDPs) are being incorporated in nonprecision approach procedures. 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 VDP will normally be identified by DME on VOR and LOC procedures and by along-track distance to the next waypoint for RNAV procedures. The VDP is identified on the profile view of the approach chart by the symbol: V.
1. VDPs are intended to provide additional guidance where they are implemented. No special technique is required to fly a procedure with a VDP. The pilot should not descend below the MDA prior to reaching the VDP and acquiring the necessary visual reference.
2. Pilots not equipped to receive the VDP should fly the approach procedure as though no VDP had been provided.​

 

[tataki]

when i looket at interview gouges, most say it is regulatory.
i am kind of confused.

 

[DC8 Flyer]

when i looket at interview gouges, most say it is regulatory.
i am kind of confused.

To me it is a bit of a grey area. Does "should not" mean You can't or is it just a suggestion?

 

[AC560]

To me it is a bit of a grey area. Does "should not" mean You can't or is it just a suggestion?

Should not does not equal do not. If you crash though they will probably toss 91.175, 91.13, etc. at you. This is similar to entering a hold where parallel, tear drop, and direct are recommended but you really can do whatever you want.

 

[Doc Holiday]

when i looket at interview gouges, most say it is regulatory.
i am kind of confused.

That's probably because these gouges have some questions regarding 121 regs in them. I listed the reg a couple of posts ago that pertains to this.

 

[BenderGonzales]

If you pass the VDP (which can be identified using time OR distance...so no excuses!) and then begin a descent from MDA, your glidepath will exceed 3 degrees. You may set up an excessive rate of descent.

In such a case you are not "continuously in a position from which a landing may be made using normal maneuvering" etc..etc..

Think like an airline pilot. Go-arounds pay more than landings.

 

[Doc Holiday]

If you pass the VDP (which can be identified using time OR distance...so no excuses!) and then begin a descent from MDA, your glidepath will exceed 3 degrees. You may set up an excessive rate of descent.

In such a case you are not "continuously in a position from which a landing may be made using normal maneuvering" etc..etc..

Think like an airline pilot. Go-arounds pay more than landings.

This is incorrect, a true VDP is assessed for obstacle clearance and PUBLISHED on an IAP at a fixed point in space. It is not determined by time.

You are referring to what is sometimes referred to as a Planned Descent Point or Time To See point, and often used interchangeably with the term "VDP". While these are a great tool for non presicion IAPs where a VDP is not published, they are neither regulatory nor do they necessarily provide for obstacle clearance.

 

[Amish RakeFight]

VDP and PDP are different things.

VDP's are published - PDP's are calculated.

Published VDP's have all of math and geometry hammered out so you don't collide with something on that particular approach.

 

[PURPLEHAZE21]

I thought VDP's pertained more towards larger aircraft who would be unable to descend prior to the MAP, while at MDA, and land under 91.175 ? The "stable" concept, which has been around for awhile (Part 135/121), appears to be making a big come back. Under part 91 ops. does the "stable" concept apply or do you just have to adhere to 91.175 ?

 

[Amish RakeFight]

VDP's can and should be used by everyone including light aircraft.

Aside from ensuring a stabilized descent, let's say you're at MDA and acquire the runway environment prior to reaching the published VDP. It wouldn't be wise to begin descent prior to reaching this point. Your descent angle would be more shallow and if you did use a 3 degree (300' descent per mile) you might run into obstacles which penetrate this angle from your MDA if begun prior to reaching the published VDP or calculated PDP.

 

[PURPLEHAZE21]

Good information....There recently was an accident in which a plane flying a LOC approach only saw the runway at MDA and decided to descend to 100 ft above TDZ (It was night). You probably figured it out...they hit an obstacle prior to the runway....maybe a VDP would have helped ?