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 are: (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 m>,
"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.

In article >,
> wrote:
>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.

But there can still be a hill below for you to descend into. Your
eyeballs can still have clear line of sight to the runway lights while
your landing gear is dragging through the treetops.

On 4 Jan 2005 10:02:48 -0500, (Roy Smith) wrote:

>But there can still be a hill below for you to descend into. Your
>eyeballs can still have clear line of sight to the runway lights while
>your landing gear is dragging through the treetops.


In which case you should hear quite a racket, and an altitude change
would be advisable.

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

There might be antennae.

Jose
--
Money: What you need when you run out of brains.
for Email, make the obvious change in the address.

> wrote in message
...
> 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.

Yes, that strikes me as the best way to make sense of the rule's intention.
Still, the rule doesn't actually say that, so I share the OP's sense of
uncertainty as to the technicality. I wonder if any FSDOs have issued
opinions on this question.

--Gary

Gary Drescher wrote:

>
>
> 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.)
>

There is no difference because the only rule that governs descending below the
minimum instrument altitude on an IAP is the 91.175 stuff pertaining to descent
below MDA (forgetting DA/H) in this case. That applies whether he has reached
the stepdown fix or not.

Gary Drescher wrote:

> > wrote in message
> ...
> > 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.
>
> Yes, that strikes me as the best way to make sense of the rule's intention.
> Still, the rule doesn't actually say that, so I share the OP's sense of
> uncertainty as to the technicality. I wonder if any FSDOs have issued
> opinions on this question.
>

What worth is a FSDO opinion? A legal interp from general counsel is fine, but
not what some inspector thinks.

Gary Drescher wrote:

> > 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.

A fix is a location defined by a point on the ground. Why would you
want to descend underground in an airplane? :-)


Matt

Roy Smith wrote:

> In article >,
> > wrote:
>
>>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.
>
>
> But there can still be a hill below for you to descend into. Your
> eyeballs can still have clear line of sight to the runway lights while
> your landing gear is dragging through the treetops.

Or the runway could be in a valley with a high tension line across it...


Matt

> wrote in message ...
> What worth is a FSDO opinion? A legal interp from general counsel is
> fine, but
> not what some inspector thinks.

I'd guess that it would be difficult for the FAA to take punitive action
against a pilot for doing something that the FSDO said in writing was ok to
do, even if the FSDO's opinion is not otherwise legally binding. (Are there
any documented instances of successful enforcement actions under such
circumstances?)

--Gary

"Matt Whiting" > wrote in message
...
> 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.
>
> A fix is a location defined by a point on the ground. Why would you want
> to descend underground in an airplane? :-)

Well, like the FAA, I don't always manage to say what I mean. :-)

--Gary

Gary Drescher wrote:
> "Matt Whiting" > wrote in message
> ...
>
>>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.
>>
>>A fix is a location defined by a point on the ground. Why would you want
>>to descend underground in an airplane? :-)
>
>
> Well, like the FAA, I don't always manage to say what I mean. :-)
>
> --Gary
>
>

The real question is: do you mean what you say? :-)


Matt

> Since the "MDA rule" only refers to MDA, and the MDA only exists on
> the final segment, I think that if you were operating below an
> altitude specified for some other segment, and had some kind of
> problem as a result, a case could be made against you if there were
> an enforcement action of some kind.

I'm 80% of the way through my IFR so I must be right. ;-)
From my understanding is that this is correct. Think about it
this way, if you were 30 miles out and you had the runway environment
in sight, a normal descent rate can be made and flight visibility was
met, can you descend below MEA/MDA? of course not. The MDA rule
is for after the FAF so you can land otherwise you can simply
choose your altitude at any point of the approach claiming all
3 items were met.

the other big thing people are missing is the approach is not only
to keep you safe but also the controller will expect you to be
along the published route. A controller can certainly vector a VFR or
IFR plane below you.....published minimum for one of the step downs is
say 3000 AGL giving enough clearance. If you are lower, something
bad could happen. This is similar to what happened to the actor (?)
a few weeks ago (If I recall correctly). In that case I believe
the actor misunderstood or incorrectly determined he was cleared
lower when he was not.


Gerald

On Tue, 04 Jan 2005 18:09:11 -0500, Matt Whiting
> wrote:

>Roy Smith wrote:
>
>> In article >,
>> > wrote:
>>
>>>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.
>>
>>
>> But there can still be a hill below for you to descend into. Your
>> eyeballs can still have clear line of sight to the runway lights while
>> your landing gear is dragging through the treetops.
>
>Or the runway could be in a valley with a high tension line across it...
>
>
>Matt


Like I said.

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

>> Well, like the FAA, I don't always manage to say what I mean. :-)
>> --Gary
> The real question is: do you mean what you say? :-)
> Matt

I know you believe you understand what you think I said, but I am not
sure you realize that what you heard is not what I meant

No, you cannot, unless you first...
- cancel IFR, or
- get a visual approach clearance, or
- get a contact approach clearance

You might get away with it, though, if you just call in to ATC, "runway
in sight" before descending.

Agreed.

I think the answer is simple.

Aren't Part 97 instrument approach procedures required fy FARs? In
which case, all minimum altitudes depicted on approach plates must be
obeyed. 91.175 allows descent below MDA or dh when certain
paramenters are met. But not descent below other minimum altitudes on
the app procedure

Stan

On 4 Jan 2005 23:19:26 -0800, wrote:

>No, you cannot, unless you first...
>- cancel IFR, or
>- get a visual approach clearance, or
>- get a contact approach clearance
>
>You might get away with it, though, if you just call in to ATC, "runway
>in sight" before descending.

On Tue, 04 Jan 2005 23:09:47 GMT, wrote:

>Since the "MDA rule" only refers to MDA, and the MDA only exists on
>the final segment, I think that if you were operating below an
>altitude specified for some other segment, and had some kind of
>problem as a result, a case could be made against you if there were
>an enforcement action of some kind.

Assuming that statement is true, PATER is within the final segment, so the
MDA rule would still apply.


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

On Wed, 05 Jan 2005 02:59:56 GMT, "G. Sylvester"
> wrote:


>I'm 80% of the way through my IFR so I must be right. ;-)
> From my understanding is that this is correct. Think about it
>this way, if you were 30 miles out and you had the runway environment
>in sight, a normal descent rate can be made and flight visibility was
>met, can you descend below MEA/MDA? of course not. The MDA rule
>is for after the FAF so you can land otherwise you can simply
>choose your altitude at any point of the approach claiming all
>3 items were met.

Although we've gotten a bit afield, in the OP's example he was considering
descent at a point within the final segment (i.e. between the FAF and the
MAP).


>
>the other big thing people are missing is the approach is not only
>to keep you safe but also the controller will expect you to be
>along the published route. A controller can certainly vector a VFR or
>IFR plane below you.....published minimum for one of the step downs is
>say 3000 AGL giving enough clearance. If you are lower, something
>bad could happen. This is similar to what happened to the actor (?)
>a few weeks ago (If I recall correctly). In that case I believe
>the actor misunderstood or incorrectly determined he was cleared
>lower when he was not.
>

Clearly bad things can happen if you are below the charted altitude for a
segment of the approach. However, the controller will not vector an
aircraft below you once you have been cleared for the approach and are past
the IAF.


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

wrote:

> This was my first thought as well.
>
> However, on reflection, the published altitudes for each of the
> segments are minimum altitudes.
>
> Since the "MDA rule" only refers to MDA, and the MDA only exists on
> the final segment, I think that if you were operating below an
> altitude specified for some other segment, and had some kind of
> problem as a result, a case could be made against you if there were
> an enforcement action of some kind.

How many angels on the head of a pin?

If in doubt, don't ignore the descent fix even if all the landing requirements of
91.175 are satisfied. Trying to make FARs black and white, absent some kind of case
law, is like arguing with your mother-in-law.

"G. Sylvester" wrote:

> > Since the "MDA rule" only refers to MDA, and the MDA only exists on
> > the final segment, I think that if you were operating below an
> > altitude specified for some other segment, and had some kind of
> > problem as a result, a case could be made against you if there were
> > an enforcement action of some kind.
>
> I'm 80% of the way through my IFR so I must be right. ;-)
> From my understanding is that this is correct. Think about it
> this way, if you were 30 miles out and you had the runway environment
> in sight, a normal descent rate can be made and flight visibility was
> met, can you descend below MEA/MDA? of course not. The MDA rule
> is for after the FAF so you can land otherwise you can simply
> choose your altitude at any point of the approach claiming all
> 3 items were met.
>
> the other big thing people are missing is the approach is not only
> to keep you safe but also the controller will expect you to be
> along the published route. A controller can certainly vector a VFR or
> IFR plane below you.....published minimum for one of the step downs is
> say 3000 AGL giving enough clearance. If you are lower, something
> bad could happen. This is similar to what happened to the actor (?)
> a few weeks ago (If I recall correctly). In that case I believe
> the actor misunderstood or incorrectly determined he was cleared
> lower when he was not.
>
> Gerald

The controller cannot vector someone below you unless they are at, or
above, the MVA. This was about a stepdown fix two miles from the runway.
30 miles out is an entirely different matter.

Matt Whiting wrote:

> Roy Smith wrote:
>
> > In article >,
> > > wrote:
> >
> >>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.
> >
> >
> > But there can still be a hill below for you to descend into. Your
> > eyeballs can still have clear line of sight to the runway lights while
> > your landing gear is dragging through the treetops.
>
> Or the runway could be in a valley with a high tension line across it...
>
> Matt

That can occur on any approach with not less than one mile visibility. The
visual segment has a 34:1 clearance criteria and a 20:1 clearance criteria.
But, either or both can be violated. If the 20:1 is violated and the
approach was updated in the past few years, the minimums (and sometimes the
entire IAP itself) will be "NA" at night.

Gary Drescher wrote:
>
>
> I'd guess that it would be difficult for the FAA to take punitive action
> against a pilot for doing something that the FSDO said in writing was ok to
> do, even if the FSDO's opinion is not otherwise legally binding

Don't count on it. It might count for something with that particular
inspector, but each FSDO is a fiefdom unto itself.

Roy Smith wrote:

> But there can still be a hill below for you to descend into. Your
> eyeballs can still have clear line of sight to the runway lights while
> your landing gear is dragging through the treetops.

If the lights ever go out, CLIMB!

"hsm" > wrote in message
ps.com...
> 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 would first get the visual approach clearance.

I would also add a note about night, even though you did not ask: many
pilots have been killed descending below minimums at night when they thought
they had the runway in sight. In fact, there have been several notable
accidents like that during the day; the recent one in Texas where a jet on
the way to pick up former President Bush, Sr., crashed may be one such.

"Jose" > wrote in message
om...
> > If you can see the runway, there ain't no hill between you and it.
>
> There might be antennae.

Yes, and these are not always depicted on approach plates.

On Wed, 05 Jan 2005 05:23:51 -0800, wrote:

>Trying to make FARs black and white, absent some kind of case
>law, is like arguing with your mother-in-law.

or wrestling with a pig.
Ron (EPM) (N5843Q, Mooney M20E) (CP, ASEL, ASES, IA)

The minimum altitude prior to reaching the stepdown fix is also the MDA
unless and until the stepdown fix is received.

JPH

Ron Rosenfeld wrote:
> On Tue, 04 Jan 2005 23:09:47 GMT, wrote:
>
>
>>Since the "MDA rule" only refers to MDA, and the MDA only exists on
>>the final segment, I think that if you were operating below an
>>altitude specified for some other segment, and had some kind of
>>problem as a result, a case could be made against you if there were
>>an enforcement action of some kind.
>
>
> Assuming that statement is true, PATER is within the final segment, so the
> MDA rule would still apply.
>
>
> Ron (EPM) (N5843Q, Mooney M20E) (CP, ASEL, ASES, IA)

On Wed, 05 Jan 2005 16:05:08 -0600, J Haggerty >
wrote:

>The minimum altitude prior to reaching the stepdown fix is also the MDA
>unless and until the stepdown fix is received.

You must be looking at a different P/C glossary than I am:

MINIMUM DESCENT ALTITUDE- The lowest altitude, expressed in feet above mean
sea level, to which descent is authorized on final approach or during
circle-to-land maneuvering in execution of a standard instrument approach
procedure where no electronic glideslope is provided.


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

On Wed, 05 Jan 2005 16:05:08 -0600, J Haggerty >
wrote:

>The minimum altitude prior to reaching the stepdown fix is also the MDA
>unless and until the stepdown fix is received.

I should add that on the approach in question, there is no published
alternate MDA to be used if the last stepdown fix is not identified.


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

On Wed, 05 Jan 2005 16:05:08 -0600, J Haggerty >
wrote:

>The minimum altitude prior to reaching the stepdown fix is also the MDA
>unless and until the stepdown fix is received.

It'd be nice if I could get all my thoughts together for one message. And
it'd also be nice if I did not always respond as if a positive comment were
argumentative :-(

Your statement is supportive of the idea that it is OK to descend below the
stepdown fix, provided the requirements of 91.175 for operating below the
MDA are met.


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

It would probably help if it was explained how the MDA is established by
AVN.
First, the MDA is established between the FAF and MAP/threshold
(whichever is last). This is the basic MDA for the procedure.
Second, the specialist will determine if it's possible to provide a
lower MDA at some point on final by adding another fix after the FAF
where the pilot can "step down" to a lower altitude. This can only be
done if there is either at least a 60 ft reduction in the MDA, or a
reduction in visibility.
Third, there has to be a suitable fix to be used as a stepdown.

If the above criteria is met, then the specialist can add a lower MDA
that is applicable after the stepdown fix. Whether the first MDA is
actually listed as an MDA in the minimums section is dependent on
whether the stepdown fix will "always" be received, or if it will only
be received by some aircraft. For RNAV (GPS) approaches, it's considered
to always be receivable by the aircraft, so only the one MDA is
published as an MDA. If it's a procedure with /DME in the procedure
name, then it's also considered always receivable by the aircraft, since
you're required to have DME to conduct the procedure due to the
procedure title.

For other procedures, such as a VOR or LOC or NDB (not xxx/DME) with a
DME or crossing radial/bearing stepdown fix, the stepdown altitude will
also be shown as the MDA, since it is the MDA for those aircraft not
capable of receiving the stepdown fix. In those cases, you will see 2
MDA's published on the procedure, since some aircraft can't benefit from
the lower MDA.

You're right, the MDA is the lowest altitude, expressed in MSL, to which
descent is authorized on final approach. And the lowest altitude,
expressed in MSL, to which descent is authorized on final prior to the
stepdown fix is the minimum altitude shown at the stepdown fix. That is
your MDA until you reach the stepdown fix.

The complication is that the selected altitude may be computed
differently depending on whether it's "always received" or just
"sometimes received". If it can only be received sometimes, it will
actually be the lowest altitude that will clear obstructions on that
segment of final between the FAF and stepdown fix. This is to benefit
those that won't be able to receive the stepdown fix.
If it can always be received, it may be artificially adjusted higher for
various reasons (provide an optimum descent gradient, provide a 300'
buffer above the floor of controlled airspace, ensure NAVAID reception
in an otherwise poor reception area, give an even 100' increment
altitude, etc)

There's an example of what can happen when an aircraft descends below
the stepdown altitude on final (and also below the MDA) at this website.
http://www.avweb.com/news/airman/184931-1.html
This particular aircraft had reported the runway in sight prior to the
stepdown fix and about a minute before he impacted rising terrain on final.


JPH

Ron Rosenfeld wrote:
> On Wed, 05 Jan 2005 16:05:08 -0600, J Haggerty >
> wrote:
>
>
>>The minimum altitude prior to reaching the stepdown fix is also the MDA
>>unless and until the stepdown fix is received.
>
>
> You must be looking at a different P/C glossary than I am:
>
> MINIMUM DESCENT ALTITUDE- The lowest altitude, expressed in feet above mean
> sea level, to which descent is authorized on final approach or during
> circle-to-land maneuvering in execution of a standard instrument approach
> procedure where no electronic glideslope is provided.
>
>
> Ron (EPM) (N5843Q, Mooney M20E) (CP, ASEL, ASES, IA)

wrote in news:hknmt05hfh1ie353a9nm8or71cnfclhn64@
4ax.com:

> On Tue, 04 Jan 2005 18:09:11 -0500, Matt Whiting
> > wrote:
>
>>Roy Smith wrote:
>>
>>> In article >,
>>> > wrote:
>>>
>>>>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.
>>>
>>>
>>> But there can still be a hill below for you to descend into. Your
>>> eyeballs can still have clear line of sight to the runway lights
while
>>> your landing gear is dragging through the treetops.
>>
>>Or the runway could be in a valley with a high tension line across
it...
>>
>>
>>Matt
>
>
> Like I said.
>
> If you can see the runway, there ain't no hill between you and it.


Yea, but a power line is just as bad as a hill.

In article >,
Andrew Sarangan > wrote:

> wrote in news:hknmt05hfh1ie353a9nm8or71cnfclhn64@
> 4ax.com:
>
> > On Tue, 04 Jan 2005 18:09:11 -0500, Matt Whiting
> > > wrote:
> >
> >>Roy Smith wrote:
> >>
> >>> In article >,
> >>> > wrote:
> >>>
> >>>>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.
> >>>
> >>>
> >>> But there can still be a hill below for you to descend into. Your
> >>> eyeballs can still have clear line of sight to the runway lights
> while
> >>> your landing gear is dragging through the treetops.
> >>
> >>Or the runway could be in a valley with a high tension line across
> it...
> >>
> >>
> >>Matt
> >
> >
> > Like I said.
> >
> > If you can see the runway, there ain't no hill between you and it.
>
>
> Yea, but a power line is just as bad as a hill.

Not really. With a power line, you at least stand a chance of just
catching the wire with the landing gear and ending up hanging upside
down from the gear until the firemen come and rescue you with a cherry
picker. It's hard to do that with a hill.

Roy Smith > wrote in news:roy-0F407F.23230406012005
@reader1.panix.com:

> In article >,
> Andrew Sarangan > wrote:
>
>> wrote in news:hknmt05hfh1ie353a9nm8or71cnfclhn64
@
>> 4ax.com:
>>
>> > On Tue, 04 Jan 2005 18:09:11 -0500, Matt Whiting
>> > > wrote:
>> >
>> >>Roy Smith wrote:
>> >>
>> >>> In article >,
>> >>> > wrote:
>> >>>
>> >>>>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.
>> >>>
>> >>>
>> >>> But there can still be a hill below for you to descend into.
Your
>> >>> eyeballs can still have clear line of sight to the runway lights
>> while
>> >>> your landing gear is dragging through the treetops.
>> >>
>> >>Or the runway could be in a valley with a high tension line across
>> it...
>> >>
>> >>
>> >>Matt
>> >
>> >
>> > Like I said.
>> >
>> > If you can see the runway, there ain't no hill between you and it.
>>
>>
>> Yea, but a power line is just as bad as a hill.
>
> Not really. With a power line, you at least stand a chance of just
> catching the wire with the landing gear and ending up hanging upside
> down from the gear until the firemen come and rescue you with a cherry
> picker. It's hard to do that with a hill.


I wonder how often that really happens. I know of only one case when a
Seattle pilot hung on a wire. I would imagine that the chance of hitting
a wire and hanging upside down is just as remote as surviving a midair
collision. I could be wrong though.

On 6 Jan 2005 21:51:54 -0600, Andrew Sarangan
> wrote:

wrote in news:hknmt05hfh1ie353a9nm8or71cnfclhn64@
>4ax.com:
>
>> On Tue, 04 Jan 2005 18:09:11 -0500, Matt Whiting
>> > wrote:
>>
>>>Roy Smith wrote:
>>>
>>>> In article >,
>>>> > wrote:
>>>>
>>>>>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.
>>>>
>>>>
>>>> But there can still be a hill below for you to descend into. Your
>>>> eyeballs can still have clear line of sight to the runway lights
>while
>>>> your landing gear is dragging through the treetops.
>>>
>>>Or the runway could be in a valley with a high tension line across
>it...
>>>
>>>
>>>Matt
>>
>>
>> Like I said.
>>
>> If you can see the runway, there ain't no hill between you and it.
>
>
>Yea, but a power line is just as bad as a hill.


Like I said,

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

On 6 Jan 2005 23:06:12 -0600, Andrew Sarangan
> wrote:

>I wonder how often that really happens. I know of only one case when a
>Seattle pilot hung on a wire. I would imagine that the chance of hitting
>a wire and hanging upside down is just as remote as surviving a midair
>collision. I could be wrong though.
>
>


Remote? The survival rate is something like 30-40%, I believe. For
example, in 2000 there were 19 midairs, with 8 non-fatal. I don't
have the actual number of people involved.

On Thu, 06 Jan 2005 21:42:04 -0600, J Haggerty >
wrote:

> then the specialist can add a lower MDA
>that is applicable after the stepdown fix. Whether the first MDA is
>actually listed as an MDA in the minimums section is dependent on
>whether the stepdown fix will "always" be received, or if it will only
>be received by some aircraft. For RNAV (GPS) approaches, it's considered
>to always be receivable by the aircraft, so only the one MDA is
>published as an MDA. If it's a procedure with /DME in the procedure
>name, then it's also considered always receivable by the aircraft, since
>you're required to have DME to conduct the procedure due to the
>procedure title.

There seems to be a disconnect between TERPs, training, AIM, etc. Not that
that is unusual.

Your explanation is clear.

However, as I mentioned in a later post, it reinforces the idea that it is
legal to descend below a SDF that occurs after the FAF, provided the
requirements of 91.175 are met.

>This particular aircraft had reported the runway in sight prior to the
>stepdown fix and about a minute before he impacted rising terrain on final.

First of all what is safe is not necessarily legal.

In the particular instance you cite, according to the report, the crew
flying was not following procedures that had been set up for the safe
operation of this aircraft. And, from the recordings, it does not appear
as if they really met all of the requirements of 91.175 before they
descended below the MDA.

Taking shortcuts (not following proper procedures) at an airport like Aspen
is fraught with hazard, moreso than at flatland airports.


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

wrote in news:mevst09cot7rjsflpa7nucm8qa1nu4fijk@
4ax.com:

> Like I said,
>
> If youcan see the runway, there ain't no hill between you and it

But if you descend below the current angle of sight, there may be. You
might be looking just barely over the top of one.

--
Regards,

Stan

On 6 Jan 2005 23:06:12 -0600, Andrew Sarangan
> wrote:



>> Not really. With a power line, you at least stand a chance of just
>> catching the wire with the landing gear and ending up hanging upside
>> down from the gear until the firemen come and rescue you with a cherry
>> picker. It's hard to do that with a hill.
>
>
>I wonder how often that really happens. I know of only one case when a
>Seattle pilot hung on a wire. I would imagine that the chance of hitting
>a wire and hanging upside down is just as remote as surviving a midair
>collision. I could be wrong though.

The odds aren't very good.
I personally know of 4 instances which is probably a small percentage,
but:

A 172 flying up a lake which turns into a river (Sanford Lake about 5
miles from me) hit a power line crossing the river (narrow section).
It tore the seats right out of the plane. No survivors. (2)

A year ago a friend and crop duster for many years took vertical stab
right off his ag plane. He got it away from the buildings along the
road but turned it into a law dart out in a field. No survivor. (1)

Some years back a Cherokee was coming into Tampa Bay Exec. It was
early morning fog and he must have been trying to get under it. He
hit the high tension lines two miles to the West of the airport. The
only thing left was the engine and looked like a piece of modeling
clay that some one had tried to roll into a ball. No survivor. (1)

(As I remember it) A couple years back a guy rented an Arrow out of
Bay City. He took a friend and the friend's son for a ride. They did
a wee bit too much low flying looking at the farm land near his
friend's place as I understand it. They discovered a power line
ahead. He pulled up and started a turn. The left wing hit the ground
wire that runs along the top of the line. It stretched that heavy
line out and broke it. The line whipped around and ended up winding
itself around the hot wires shutting down power for several square
miles. (3 survivors)

The Arrow? Well, after missing the ground by inches, while probably
trying to imitate a Frisbee (TM), they headed back to Bay City.
Parked the plane, took his friend's son home and headed for a bar.
Even though ill advised I can truely understand their desire for a
drink at the time (and the removal of the seat cushions.)

One of the guys at Bay City (3CM) noticed the Arrow looked kinda
different setting out there on the ramp. At first he thought they had
just forgotten to put the flaps up so he got in to put the flaps up,
but they wouldn't move. Then he got out to look at the plane. The
wings were actually skewed to the left and by quite a bit. I believe
there was something like a 3 to 4 inch gap between the leading edge
and the fuselage on the pilot's side. The wing was torqued so bad
they couldn't get the flaps back up.

Unfortunately the renter had neglected to mention he had encountered a
any difficulties on the flight.

The police found him and his friend at the bar.

So the total was 4 airplanes with three of the four killing all on
board. OTOH there were 3 survivors out of 7.

As I understand they actually rebuilt the Arrow and it's still flying.
The kicker though: They had sold the Arrow and the new owner was to
pick it up the next morning. Needless to say they had to call him and
ask for a delay. (I don't remember if he actually ended up buying the
plane after that or not. Seems like he did)

I can see it now: "Oh, BTW, before we go out we have discovered some
minor problems we need to take care of before you take it home."

Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com
>
>
>
>
>

On Fri, 07 Jan 2005 12:18:21 GMT, wrote:


>
>Like I said,
>
>If youcan see the runway, there ain't no hill between you and it

Depends on your rate of descent. That runway can disappear pretty
fast.

Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com

On 6 Jan 2005 23:06:12 -0600, Andrew Sarangan
> wrote:

>I wonder how often that really happens. I know of only one case when a
>Seattle pilot hung on a wire. I would imagine that the chance of hitting
>a wire and hanging upside down is just as remote as surviving a midair
>collision. I could be wrong though.

Not related to the original "descent below minimums"-question, but
anyway:

A couple of years ago our club lost an Archer. It ran out of gas about
20 miles from the destination, but just over a glider airfield with
plenty of runway available. The pilot misjudged the gliding capability
and flew a too-wide traffic pattern. The airfield was located on a
plateau, and about half a mile before the threshold there was a
powerline crossing the approach path at about field elevation.

Our poor plane ended up dangling in that powerline and its occupants
had to be freed by the local fire brigade. One of them spent a few
nights in hospital, but nothing really serious.

Tobias

In article >,
says...

> Like I said, if you can see the runway, there ain;t no hill between
> you and it.

http://www.aopa.org/pilot/never_again/2002/na0204.html

--Carlos V.

On Sat, 08 Jan 2005 07:10:00 GMT, Carlos Villalpando
> wrote:

>In article >,
says...
>
>> Like I said, if you can see the runway, there ain;t no hill between
>> you and it.
>
>http://www.aopa.org/pilot/never_again/2002/na0204.html
>
>--Carlos V.


Nothing in this article that contradicts this statement:

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

>>http://www.aopa.org/pilot/never_again/2002/na0204.html

> Nothing in this article that contradicts this statement:
> If you can see the runway, there ain't no hill between you and it.

Not true. What =is= true is "If you can see the runway, there ain't
no hill between your eyeballs and it." However, there is more "you"
below your eyeballs. So your statement (which you keep repeating on
technical grounds) is incorrect - on technical grounds.

Further, as has already been pointed out, there is a lot of airplane
below your eyeballs which can run into the hill your eyeballs just
missed. This is the point of disagreeing with your statement. It
implies safety, and delivers the opposite.

Jose
--
Money: What you need when you run out of brains.
for Email, make the obvious change in the address.

On Sat, 08 Jan 2005 15:36:51 GMT, Jose >
wrote:

>Further, as has already been pointed out, there is a lot of airplane
>below your eyeballs which can run into the hill your eyeballs just
>missed


Not with about 6 ft of visibility or more.

Of course, with 6 ft of visibility, you probably ain't seeing the
runway either.

In article >,
wrote:

> On Sat, 08 Jan 2005 15:36:51 GMT, Jose >
> wrote:
>
> >Further, as has already been pointed out, there is a lot of airplane
> >below your eyeballs which can run into the hill your eyeballs just
> >missed
>
>
> Not with about 6 ft of visibility or more.
>
> Of course, with 6 ft of visibility, you probably ain't seeing the
> runway either.

On a dark night, treetops can be totally invisible. Try flying a visual
approach into HPN's 29. All you see is runway lights surrounded by inky
blackness. If you get too low, the (displaced) threshold lights just
suddenly wink out for no apparent reason.

It's easy to imagine being on a flight path which drags your landing
gear through the treetops and not being aware of it until it's too late.

On Sat, 08 Jan 2005 11:06:33 -0500, Roy Smith > wrote:

> If you get too low, the (displaced) threshold lights just
>suddenly wink out for no apparent reason.


No apparent reason?

The obvious reason is, you are getting too low.

Gentlemen:

The idea that 'if I can see the runway then there is nothing between me
and it' is both true and deadly, especially at night. It presumes that
your flight path is the same as your line of sight, and this is not
always so.

Pick up ASF's video package on Controlled Flight into Terrain, and pay
close attention to the section on the Black Hole Approach. Many a
pilot has made the mistake of depending on the 'I can see the threshold
cue,' when in fact they are executing what is technically called a
'constant visual angle' approach. The trees suddenly fill the
windscreen, and by the time they see it it is usually too late to
initiate a successful go around.

Typically, if the pilots survive to be interviewed, they were convinced
they were on a normal glide path right up until the moment before
impact.

Gene

> wrote in message
oups.com...
>
> Pick up ASF's video package on Controlled Flight into Terrain, and pay
> close attention to the section on the Black Hole Approach. Many a
> pilot has made the mistake of depending on the 'I can see the threshold
> cue,' when in fact they are executing what is technically called a
> 'constant visual angle' approach. The trees suddenly fill the
> windscreen, and by the time they see it it is usually too late to
> initiate a successful go around.
>

When it happened to me (black hole illusion), I became aware of the
treetops that I was descending into only when they were illuminated by the
wingtip strobe lights. If I had not had strobes, I would have dragged the
gear into the trees without ever losing sight of the runway (until impact).

> It presumes that if one ALWAYS sees the target, there will be nothing
> between the aircraft and the target.

.... and that presumption is deadly false. There may be nothing
between the eyeball and the target, but the aircraft dangles below.
Furher, there can be invisible barriers between the aircraft and the
target - wires come to mind, especially at night. True, wires aren't
a hill, but neither are tree branches, both of which could spoil your day.

> If one lost the target 5 seconds ago on a descent, one can regain
> the target and clear it by returning to the altitude he was at 5
> seconds ago, and remaining level.

In that time you are moving forward. The object that caused you to
lose sight of the target may well be wrapped around you by then.

"If you never hit anything, you won't crash."

Jose
--
Money: What you need when you run out of brains.
for Email, make the obvious change in the address.

> In a GA aircraft the aircraft dangles 5 feet below eye level.
>
> Are you seriously suggesting that you can't see objects 5 feet below
> the aircraft, with visibility good enough to see distant runway
> lights?

Yep. That's exactly what I'm saying. And in five seconds the
aircraft can easily go five hundred feet.

Jose
--
Money: What you need when you run out of brains.
for Email, make the obvious change in the address.

In article >,
wrote:

> On Sat, 08 Jan 2005 21:31:33 GMT, Jose >
> wrote:
>
> >... and that presumption is deadly false. There may be nothing
> >between the eyeball and the target, but the aircraft dangles below.
> >Furher, there can be invisible barriers between the aircraft and the
> >target - wires come to mind, especially at night. True, wires aren't
> >a hill, but neither are tree branches, both of which could spoil your day.
>
>
> In a GA aircraft the aircraft dangles 5 feet below eye level.
>
> Are you seriously suggesting that you can't see objects 5 feet below
> the aircraft, with visibility good enough to see distant runway
> lights?
>
> C'mon.

At night? Absolutely.

wrote:
> On Sat, 08 Jan 2005 21:31:33 GMT, Jose >
> wrote:

> Are you seriously suggesting that you can't see objects 5 feet below
> the aircraft, with visibility good enough to see distant runway
> lights?
>
> C'mon.

Yes, if the ambient lighting is not bright (dusk, dawn, fog, mist, etc)
you could miss the fact that you're about to hit dirt as you descend
toward the runway, even though the runway is in sight.
NTSB reports are full of stories about pilots that had the runway in
sight and still hit the ground.
Remember the C-130 that bounced on the ground a half mile short of the
runway in Kuwait a couple of years ago and killed 3 passengers when the
gear busted through the floor of the airplane? He had the approach
lights in sight, too. Perfectly good airplane with no problems, but
another controlled flight into terrain.

JPH

wrote:
> On Sat, 08 Jan 2005 21:31:33 GMT, Jose >
> wrote:
>
>
>>In that time you are moving forward. The object that caused you to
>>lose sight of the target may well be wrapped around you by then.
>
>
>
> In 5 seconds? With visibility good enough to see the runway?
>
> Give me a break.

You've never actually flown at night, in a remote location, have you?

Happy Flying!
Scott Skylane

On Sat, 08 Jan 2005 22:35:52 GMT, Jose >
wrote:

>Yep. That's exactly what I'm saying. And in five seconds the
>aircraft can easily go five hundred feet.


And about 40-80 feet vertically, which can be regained in about 2-4
seconds

On Sat, 08 Jan 2005 18:13:33 -0600, J Haggerty
> wrote:

>NTSB reports are full of stories about pilots that had the runway in
>sight and still hit the ground.


NTSB reports are chuck full of bad piloting stories.

On Sat, 08 Jan 2005 15:16:17 -0900, Scott Skylane
> wrote:

wrote:
>> On Sat, 08 Jan 2005 21:31:33 GMT, Jose >
>> wrote:
>>
>>
>>>In that time you are moving forward. The object that caused you to
>>>lose sight of the target may well be wrapped around you by then.
>>
>>
>>
>> In 5 seconds? With visibility good enough to see the runway?
>>
>> Give me a break.
>
>You've never actually flown at night, in a remote location, have you?
>
>Happy Flying!
>Scott Skylane


Actually, I have. In hilly country at that.

It's where I learned that when making a visual approach to an airport
at night, and the runway threshold lights start to disappear, that one
needs to get some altitude back in a hurry and keep visual contact
with the approach end of the runway at all times.

Obviously, many pilots have some other way of avoiding terrain,
although I haven't quite figured out what it is, exacty. (except to
keep the gear up so you don't drag them in the trees which are 5 feet
below the aircraft but for some reason not visible, which is a
phenomenon I must say I find highly interesting. 5 feet ain't that
far, when you really stop and think about it.)

Then of course, there's the even more interesting question of how you
know something is 5 feet away if you can'tsee it..

According to the local automobile association here, it takes (on average)
0.75 seconds to perceive a need to brake, and (on average) 0.75 seconds to
figure out what action is needed and execute it. (Geek that I am, I still
have my old driver's training manual...) Assuming these stats can be applied
to this problem, it will take 1.5 seconds from the moment you perceive the
terrain for you to take corrective action. Assuming 500 fpm, that's about
12.5 feet of descent, not 5.

Now add to that the altitude you lose if you happen to be watching some
other traffic, tuning a radio, setting an OBS, consulting a chart, etc -
even if it just takes you one second, the safety margin's now up past 20
feet. Also take into account that you're not seeing a big red danger sign
flashing in front of you; rather, you need to react to dark shapes in your
peripheral vision.

Add to this a moonless night, or a failed landing light, or a
steeper-than-usual descent, or whatever...

-Rob

> wrote in message
...
> On Sat, 08 Jan 2005 22:35:52 GMT, Jose >
> wrote:
>
>>Yep. That's exactly what I'm saying. And in five seconds the
>>aircraft can easily go five hundred feet.
>
>
> And about 40-80 feet vertically, which can be regained in about 2-4
> seconds

> I must confess, however, I don't know how you would know for sure
> that they were only 5 feet away since you admittedly wouldn't have
> been able to have seen them.

When you drag your landing gear through them, they are five feet away.

>>Yep. That's exactly what I'm saying. And in five seconds the
>>aircraft can easily go five hundred feet.
>
> And about 40-80 feet vertically, which can be regained in about 2-4
> seconds

2-4 seconds is another 200-400 feet forward We're up to almost a
thousand feet horizontally and maybe 80 feet vertically.

> NTSB reports are chuck full of bad piloting stories.

.... like descending the plane into trees while your eyeball has the
lights in sight.

> ...I learned that when making a visual approach to an airport
> at night, and the runway threshold lights start to disappear, that one
> needs to get some altitude back in a hurry and keep visual contact
> with the approach end of the runway at all times.

.... from which it does =not= follow that keeping the threshold lights
in sight prevents CFIG.

Jose
--
Money: What you need when you run out of brains.
for Email, make the obvious change in the address.

On Sun, 09 Jan 2005 06:02:27 GMT, Jose >
wrote:

>... from which it does =not= follow that keeping the threshold lights
>in sight prevents CFIG.


Well, please, share your technique with the rest of us.

On Sun, 09 Jan 2005 06:02:27 GMT, Jose >
wrote:

>When you drag your landing gear through them, they are five feet away.


So you are saying that you have actually dragged your landing gear
through treetops on an approach at night?

On Sun, 09 Jan 2005 05:08:34 GMT, "Rob" > wrote:

>Now add to that the altitude you lose if you happen to be watching some
>other traffic, tuning a radio, setting an OBS, consulting a chart, etc -


Setting OBS's and consulting charts on an descent to a runway at
night?

I think I'm beginning to understand the problem...

On Sun, 09 Jan 2005 05:08:34 GMT, "Rob" > wrote:

>Also take into account that you're not seeing a big red danger sign
>flashing in front of you; rather, you need to react to dark shapes in your
>peripheral vision.


The fact that the threshold lights are disappearing IS INDEED a big
red danger sign in front of you. Runway lights don't disappear all
at once, they disappear gradually, at a rate consistent with your rate
of descent. The nearest ones disappear first. When the nearest
runway light disappears, stop the descent IMMEDIATELY. Hold your
friggin altitude, as long as remaining lights are still visible,
otherwise start climbing.

Keep the friggin lights always in sight, and you won't hit any hill
(except for these mysterious treetops that are 5 feet below us that
we can't see but we can hear as our gear drags through them. Good
luck with those, if you ever encounter them).


And it's not the "dark shapes in my peripheral vision" that I have to
worry about, it's what's in FRONT of me that counts.

>>... from which it does =not= follow that keeping the threshold lights
>>in sight prevents CFIG.
>
> Well, please, share your technique with the rest of us.

My technique is to not make contact with anything except the runway.
It works every time. If you do not hit anything, you won't crash.

Seriously - you seem to be confusing "if X happens, do Y" with "if you
do Y, X won't happen" They are not the same.

In a VFR pattern at night, I fly a steeper approach than usual. IFR
(day or night) I don't descend below minimums until I can make that
kind of approach... and...

>>When you drag your landing gear through them, they are five feet away.
>
> So you are saying that you have actually dragged your landing gear
> through treetops on an approach at night?

....so far I have not had experimentally verified the theoretical
notion that I can tell how far the trees are from me by hitting them.
Nonetheless, I feel confident that it is true. (and of course useless)

Jose
--
Money: What you need when you run out of brains.
for Email, make the obvious change in the address.

On Sun, 09 Jan 2005 15:31:43 GMT, Jose >
wrote:

>In a VFR pattern at night, I fly a steeper approach than usual. IFR
>(day or night) I don't descend below minimums until I can make that
>kind of approach... and...


This is totally subjective and guarantees nothing other than you will
crash at a "steeper"angle (whatever that is, since one man's "steep"
is another man's "shallow".

(Unless of course, you keep the runway lights in sight at all times.
In that case you have a chance.)

> This is totally subjective and guarantees nothing other than you will
> crash at a "steeper"angle (whatever that is, since one man's "steep"
> is another man's "shallow".

Correct. There are no guarantees. And keeping the runway lights in
view is also no guarantee. You could probably see the runway lights
from the crash site.

I just make sure I don't hit anything. That has kept me from crashing
for twenty years.

Jose
--
Money: What you need when you run out of brains.
for Email, make the obvious change in the address.

On Sun, 09 Jan 2005 15:47:14 GMT, Jose >
wrote:

>Correct. There are no guarantees. And keeping the runway lights in
>view is also no guarantee. You could probably see the runway lights
>from the crash site.
>
>I just make sure I don't hit anything. That has kept me from crashing
>for twenty years.
>
>Jose


Now you're saying the crash site would be on the airport side of the
mountain? Because you sure wouldn't see runway lights on the other
side.

This is your biggest stretch yet.

Anyway, good luck on the next twenty. I'm outta here on this one.

On Sun, 09 Jan 2005 17:23:16 GMT, wrote:

>>Correct. There are no guarantees. And keeping the runway lights in
>>view is also no guarantee


Exactly. One can only maximize one's chances.

And I'm sure most people would agree that one has a better chance of
making a runway if the runway lights are in sight than if they are not
in sight.

I am just as sure that you will disagree.

But like I said, I'm outta here on this one.

But let me leave you with this one thought, which I regard as an
absolute certainty:

If you can see the runway lights, there ain't no mountain between you
and them, and this time I will add, "along your line of sight ", to
keep the anal-retentives happy.

Use that fact as you please, or ignore it, as you please.

And that is my final word on this subject, and I thank you and others
for a most interesting discusssion.

On Sun, 09 Jan 2005 12:49:03 GMT, wrote:

>On Sun, 09 Jan 2005 05:08:34 GMT, "Rob" > wrote:
>
>>Now add to that the altitude you lose if you happen to be watching some
>>other traffic, tuning a radio, setting an OBS, consulting a chart, etc -
>
>
>Setting OBS's and consulting charts on an descent to a runway at
>night?

IF IFR it's part of the drill.

>
>I think I'm beginning to understand the problem...

It's called double checking your approach parameters.
I always double check while coming down hill. You may have a fix in
there too.

As this is on an IFR group I'm assuming you are talking an IFR
approach.

The problem with watching the airport lights is on descent most planes
are not flying a straight line to the lights except for the last part
of the final.

Treat a night approach into a strange airport as if it were an IFR
approach.

1. Know the airport area
2. Know the approach for the specific runway even if VFR.
3. Stay above minimum sector altitudes even if VFR
4 Once where you can safely descend.. watch the VASI
5. Stay on or above the VASI.

When IFR I still carry sectionals. Before receiving my instrument
rating I always carried approach charts in addition to my sectionals.
No, I didn't fly the full approaches, but I did stay above the minimum
sector and segment altitudes. I still fly VFR at night and I still
carry the approach charts for those areas.

BTW, if you do get on the VASI too far out, it may literally take you
through the tops of the trees on a hill outside the airport area.

Any one flying VFR into a strange airport at night should be a tad
anal retentive when it comes to what they are doing.

Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com

> It's where I learned that when making a visual approach to an airport
> at night, and the runway threshold lights start to disappear, that one
> needs to get some altitude back in a hurry and keep visual contact
> with the approach end of the runway at all times.

that's reasonable enough but it is VERY easy to completely not
see power cables/telephone lines or tops of trees (say with no leaves)
and still have lights in the background clearly in sight. It only
takes one cable or some tree branches to ruin a good night.
stand 100 feet away from a car with its headlight towards you. Have
some one put a stick through the beam. You won't see it or barely
see it. Do that a mile away and you will completely not see it.


Gerald Sylvester

> Well, I must say I cannot imagine a situation where one could see
> distant runway lights yet not be able to see objects 5 feet away.
>
> If you say it's possible, I'll have to take your word for it.

it's very easy to imagine. Take a fast telephote camera lens
(300mm/2.8, 200mm/f2). Focues on a object at infinity and try
to pick out objects nearby. By default, you will have the widest
aperature and shallowest depth of field. You won't see a thing nearby
that you can clearly distinguish. This is *exactly* what is
happening here. Your eyes are focusing on the runway at infinity that
has bright lights relative to the dark tree limbs. You can't possibly
see them.

The better question, I know you can see and avoid many trees or other
obstacles. What obstacles did you not see? You'll never know.

Gerald

On Sun, 09 Jan 2005 21:44:36 GMT, "G. Sylvester"
> wrote:

>
>> It's where I learned that when making a visual approach to an airport
>> at night, and the runway threshold lights start to disappear, that one
>> needs to get some altitude back in a hurry and keep visual contact
>> with the approach end of the runway at all times.
>
>that's reasonable enough but it is VERY easy to completely not
>see power cables/telephone lines or tops of trees (say with no leaves)
>and still have lights in the background clearly in sight. It only
>takes one cable or some tree branches to ruin a good night.
>stand 100 feet away from a car with its headlight towards you. Have
>some one put a stick through the beam. You won't see it or barely
>see it. Do that a mile away and you will completely not see it.
>
>
>Gerald Sylvester

No argument there. That can even be the case in broad daylight, as
many a crop duster can attest.

On Sun, 09 Jan 2005 14:32:58 -0500, Roger
> wrote:

>>Setting OBS's and consulting charts on an descent to a runway at
>>night?
>
>IF IFR it's part of the drill.


This whole discussion is about making visual approaches to a runway at
night.

However, if you are my student, you aren't looking at charts while
descending inside the FAF.

you want to look at charts inside the FAF, you level off first. If
it means a missed, so be it.