Descent Prior To Vdp?

Fri May 19, 2000 10:57 pm

In the US, under part 91, is it legal to descend below the MDA prior to reaching the VDP (when depicted) given that the required visual cues for descent below the MDA are met?
Posts: 1066
Joined: Fri Mar 16, 2007 1:29 pm

RE: Descent Prior To Vdp?

Sat May 20, 2000 2:48 am

VDP's or VRP's (Visual Descent/Reference Points) depending on your carrier, assist you to complete a non-precision approach using a stabilized descent profile. They are used primarily by larger jet aircraft. The rationale of using them assumes that if you don't have the required visual reference at the VDP/VRP, you will commence a go-around, as levelling off and waiting for the MAP (Missed Approach Point) would not place you in the proper "slot" for landing - you would become destabilized and you would not land in the touchdown zone, so why bother. In a smaller airplane, it is relatively easy to get in quite close at MDA and still land safely and handily.

Sorry to go into that explanation, as I'm sure you know all that, but many don't! Getting to your question, it is my understanding that you can, if not doing so means missing the approach. However, it must be done with extreme caution. The applicable FAR 91.175 is referred to in the Arrival Procedures of the AIM section 5. However upon reading 91.175, there is no mention of VDP. There is a reference to continuing to land using a "normal rate of descent using normal manoeuvres".

I don't know what talking with FAA folks is like, but a lot of times in Canada when you have a specific question like this, the number of different responses is directly proportional to the number of inspectors you ask!

My position in instances like this is to use common sense and ask 1/ Is it safe? and 2/ Is it legal? Where the book is silent, you will live long and prosper with these two guidelines!

To close, this is only my opinion based in large part upon doing hundreds of non-precision approaches to minimums.

Best Regards,

Posts: 2451
Joined: Sat Feb 26, 2000 6:18 pm

RE: Descent Prior To Vdp?

Sat May 20, 2000 7:00 am

To answer your question, YES YOU CAN.
In fact you may even be at MDA before reaching the VDP. VDP is advisory only and has no legal meaning.

RE: Descent Prior To Vdp?

Sat May 20, 2000 8:29 am

Hey !

I agree with BUFF on different points:

1/ It's true that you'll have different answer if you ask the same question to several different FAA ASI, especially if they are from different region !!!

2/ Your rule to operate blo minimums is good (first CRM & common sense, then rules).

3/ operations blo DH/MDA are authorized when you have: A/ Prescribed visibility B/ Normal maneuver to land C/ Red side bars or REIL to descend 100ft above TDZE



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