descent below minimums

Can I descent below minimums on an intermediate stepdown segment of an
IFR approach if I have the runway enviroment in sight?
On a very steep approach such as the backcourse loc-A to Santa
Maria,CA, I would like to start descending below 1700 feet prior to
reaching PATER, in order to facilitate a more comfortable decent in
VMC. Legal or do I first need a visual approach clearance?

hsm wrote:

Can I descent below minimums on an intermediate stepdown segment of an
IFR approach if I have the runway enviroment in sight?
On a very steep approach such as the backcourse loc-A to Santa
Maria,CA, I would like to start descending below 1700 feet prior to
reaching PATER, in order to facilitate a more comfortable decent in
VMC. Legal or do I first need a visual approach clearance?

Having the runway environment is sight is one of two requirements. The
other is being in a position to make a normal descent for a normal
landing. That is somewhat your call depending upon the airplane. But,
you would be suggesting a shallow approach, which is far harder to justify
than a steep approach. The reason the stepdown is there is to keep you
from hitting the hills southeast of the airport.

Personally, I would never consider busting PATER if IFR. I would dump it
over at PATER to pick up the VGSIs.

On 3 Jan 2005 23:18:15 -0800, "hsm" wrote:

Can I descent below minimums on an intermediate stepdown segment of an
IFR approach if I have the runway enviroment in sight?
On a very steep approach such as the backcourse loc-A to Santa
Maria,CA, I would like to start descending below 1700 feet prior to
reaching PATER, in order to facilitate a more comfortable decent in
VMC. Legal or do I first need a visual approach clearance?

I believe you can so long as you meet all the requirements of 14 CFR
91.175.

An approach like the one you cite is purposely published without
straight-in minimums because the descent angle exceeds some FAA number for
an allowable straight-in approach. In my Mooney, I don't think a 500-600
ft/min descent is unreasonable, but YMMV. I prefer a steep approach in
order to allow for reaching the airport in the event of engine failure.

If it were a strange airport, I'd certainly want better than MVFR to
descend below 1700' at PATER.


Ron (EPM) (N5843Q, Mooney M20E) (CP, ASEL, ASES, IA)

On 3 Jan 2005 23:18:15 -0800, "hsm" wrote:

Can I descent below minimums on an intermediate stepdown segment of an
IFR approach if I have the runway enviroment in sight?
On a very steep approach such as the backcourse loc-A to Santa
Maria,CA, I would like to start descending below 1700 feet prior to
reaching PATER, in order to facilitate a more comfortable decent in
VMC. Legal or do I first need a visual approach clearance?

If you are executing a published IAAP, there is no "visual approach
clearance".

You need 3 things to descend below the MDA (DA),they a (a) runway
environment in sight (b)can descend using normal maneuvers, normal
rates of descent (c) the flight visibility specified in the approach.

wrote in message ...

hsm wrote:

Can I descent below minimums on an intermediate stepdown segment of an
IFR approach if I have the runway enviroment in sight?
On a very steep approach such as the backcourse loc-A to Santa
Maria,CA, I would like to start descending below 1700 feet prior to
reaching PATER, in order to facilitate a more comfortable decent in
VMC. Legal or do I first need a visual approach clearance?

Having the runway environment is sight is one of two requirements. The
other is being in a position to make a normal descent for a normal
landing.

You're citing the rules for descending below an MDA or DA. But the question
is about descending below an intermediate fix.

That is somewhat your call depending upon the airplane. But,
you would be suggesting a shallow approach, which is far harder to justify
than a steep approach.

In this case, the suggestion is for a normal descent rate, rather than a
steep approach. (Again, though, the regulation that specifies a normal
descent rate is not pertinent here.)

--Gary

On Tue, 4 Jan 2005 07:40:26 -0500, "Gary Drescher"
wrote:

You're citing the rules for descending below an MDA or DA. But the question
is about descending below an intermediate fix.


If you have the requirements for descending below the MDA, you have
the requirements for descending below any intermediate altitudes.

But you make a good point.

The altitudes published on an approach are generally minimum
altitudes, unless there is a solid line over the altitude specified,
then it is a maximum altitude, and if there are two lines, it's a
mandatory altitude.

Int his case, unless he has the requirements to go below the MDA, the
answer would be "no".

wrote in message
...
On Tue, 4 Jan 2005 07:40:26 -0500, "Gary Drescher"
wrote:

You're citing the rules for descending below an MDA or DA. But the
question
is about descending below an intermediate fix.

If you have the requirements for descending below the MDA, you have
the requirements for descending below any intermediate altitudes.

Yes, but the way 91.175c puts it is "no pilot may operate...below the
authorized MDA or... below the authorized DH unless--...". Technically,
that doesn't even say you can go below the MDA or DH (that would be "a pilot
may operate below... if and only if--..."), though that's obviously what the
FAA meant. So as it stands, 91.175c (presumably) is meant to waive the
MDA/DH requirement under the specified conditions, but it's not obvious that
it's meant to waive the even stricter requirement given by a step-down
altitude, at a location where the step-down altitude applies. (Is the MDA/DA
even defined to apply during the approach segment where a higher step-down
altitude applies?)

--Gary

On Tue, 4 Jan 2005 08:01:21 -0500, "Gary Drescher"
wrote:

Yes, but the way 91.175c puts it is "no pilot may operate...below the
authorized MDA or... below the authorized DH unless--...". Technically,
that doesn't even say you can go below the MDA or DH (that would be "a pilot
may operate below... if and only if--..."), though that's obviously what the
FAA meant. So as it stands, 91.175c (presumably) is meant to waive the
MDA/DH requirement under the specified conditions, but it's not obvious that
it's meant to waive the even stricter requirement given by a step-down
altitude, at a location where the step-down altitude applies. (Is the MDA/DA
even defined to apply during the approach segment where a higher step-down
altitude applies?)

--Gary


Oh, I think most definitely.

The rule is obviously designed to allow the pilot to descend for
landing as soon as the requirements for a safe execution of the visual
portion of the approach has been met..

I don't see why an intermediate segment altitude would override that,
with the caveat that one needs to be absolutely certain that visual
conditions will remain the rest of the way.

After all, we have the runway environment in sight, don't forget, so
we are probably talking at least 2-3 miles or more visibility, if we
see the runway environment at a stepdown altitude.

In article om,
"hsm" wrote:

Can I descent below minimums on an intermediate stepdown segment of an
IFR approach if I have the runway enviroment in sight?
On a very steep approach such as the backcourse loc-A to Santa
Maria,CA, I would like to start descending below 1700 feet prior to
reaching PATER, in order to facilitate a more comfortable decent in
VMC. Legal or do I first need a visual approach clearance?

I've read the other responses to this, and I'm going to chime in with a
weasel answer:

1) I'm not really sure if it's technically legal or not.

2) Unless you crashed, nobody would ever notice or care

3) The stepdown is there for a reason -- to keep you off the hills under
the approach path. When deciding whether to descend, I'd be more
worried about whether you had the hills in sight than if you had the
runway in sight. For example, at night, the runway might be lit up like
a christmas tree, but the hills might be invisible.

4) It's a 6000 foot runway; what looks like a steep approach to the
threshold isn't quite so steep an approach to the middle of the runway,
and you'd still have 3000 feet left (twice what you need in any spam
can).

On Tue, 04 Jan 2005 09:16:52 -0500, Roy Smith wrote:

For example, at night, the runway might be lit up like
a christmas tree, but the hills might be invisible.


If you can see the runway, there ain't no hill between you and it.