Descending prior to the VDP?

Sure, but it doesn't answer my question which more a regulatory one. Are
you "not supposed to" or "not authorized to"?

Capt.Doug wrote:
"Bob Gardner" wrote in message If you
fly the approach as if no VDP is provided, you will maintain the MDA until
you either pick up the runway visually or reach the MAP.


If I pass the VDP without seeing the runway environment, I know that I won't
likely make the runway from the MAP. After passing the VDP, I start
preparing for the missed approach.

D.

"MH" wrote in message Sure, but it doesn't answer my question which
more a regulatory one. Are
you "not supposed to" or "not authorized to"?

If you can maintain suitable cloud clearance and maintain suitable
visibility, you can descend prior to VDP legally. This practice is frowned
upon since descending before VDP puts you into unprotected airspace. You may
have visibility which is sufficient to keep the runway in sight, but you may
not see the antenna farm that the approach was designed to keep you over.

D.

The FAR require you to have the runway environment in sight before
descending from the MDA. Reaching VDP is not an authorization to
descend below MDA. You must have the runway environment in sight. The
purpose of VDP is to help you make a comfortable glide to the runway.
You can treat the VDP as the point beyond which you cannot make a
normal landing to the runway. If you pass the VDP without runway in
sight, start getting ready for the missed approach. Then begin the
missed approach after passing the MAP.



MH wrote in message ...
Sure, but it doesn't answer my question which more a regulatory one. Are
you "not supposed to" or "not authorized to"?

Capt.Doug wrote:
"Bob Gardner" wrote in message If you
fly the approach as if no VDP is provided, you will maintain the MDA until
you either pick up the runway visually or reach the MAP.


If I pass the VDP without seeing the runway environment, I know that I won't
likely make the runway from the MAP. After passing the VDP, I start
preparing for the missed approach.

D.

This is my understanding as well, the VDP is the optimal point at which
to start the descent to the runway if 1. the visibility requirements are
met, 2. the aircraft is continously in a position where it can land
using normal maneuvering and descent rates, and 3. has the runway
environment in sight.

The longer you fly after passing the VDP, the harder it becomes to make
the landing. This does not mean that you're not ALLOWED to descend prior
to the VDP, and in fact you very well may be if for example the VDP is
identified through a dme distance, and the plane doesn't have a dme
onboard. In that case, you level off at the MDA and upon establishing
visual contact with the runway, you descend as you deem appropriate and
land. This MAY result in you descending below the MDA prior to the VDP,
but you wouldn't know it. If the approach is designed correctly then the
point where it feels natural to start the descent to the runway should
more or less coincide with the VDP anyway so it shouldn't be that big of
a problem.