Reasoning behind course reversal

[Michael 182]

What is the reasoning behind the required course reversal in many
approaches? It's hard to believe that I will be safer flying the racetrack
and then the approach to the runway than simply flying to the IAF and
proceeding inbound - especially with GPS guidance. I have no problem flying
the full published course, done it many times, I'm just curious why they are
designed that way.

Michael

[John R Weiss]

"Michael 182" > wrote...
> What is the reasoning behind the required course reversal in many
> approaches? It's hard to believe that I will be safer flying the racetrack
> and then the approach to the runway than simply flying to the IAF and
> proceeding inbound - especially with GPS guidance. I have no problem flying
> the full published course, done it many times, I'm just curious why they are
> designed that way.

Many are for altitude loss. Terrain outside the IAF may prohibit lower altitude
until established on the Approach, and min IAF altitude is too high for a
reasonable descent.

Unless it's a GPS approach, the procedure was not designed for GPS guidance, and
must be designed with all the TERPS constraints in mind.

[Michael 182]

OK, this makes sense, especially since most of the ones I fly are along the
Colorado Front Range. Assuming you were coming in from the west I can see
how the course reversal would give you a protected space to descend in.

Thanks,

Michael


"John R Weiss" > wrote in message
news:bcQYb.7844$4o.29910@attbi_s52...
> "Michael 182" > wrote...
> > What is the reasoning behind the required course reversal in many
> > approaches? It's hard to believe that I will be safer flying the
racetrack
> > and then the approach to the runway than simply flying to the IAF and
> > proceeding inbound - especially with GPS guidance. I have no problem
flying
> > the full published course, done it many times, I'm just curious why they
are
> > designed that way.
>
> Many are for altitude loss. Terrain outside the IAF may prohibit lower
altitude
> until established on the Approach, and min IAF altitude is too high for a
> reasonable descent.
>
> Unless it's a GPS approach, the procedure was not designed for GPS
guidance, and
> must be designed with all the TERPS constraints in mind.
>

[Rick Glasser]

On Wed, 18 Feb 2004 20:32:22 +0000, Michael 182 wrote:

> What is the reasoning behind the required course reversal in many
> approaches? It's hard to believe that I will be safer flying the racetrack
> and then the approach to the runway than simply flying to the IAF and
> proceeding inbound - especially with GPS guidance. I have no problem flying
> the full published course, done it many times, I'm just curious why they are
> designed that way.
>
> Michael

It is also to allow you to get "established" and stabilized on the inbound
course prior to the FAF, especially where the IAF and FAF are the same.
If you just turned inbound at the fix, precious distance would be wasted
while still getting established and technically you should not be
descending until established.

--
Rick/JYO
PP-ASEL-IA
remove 'nospam' to reply

[Michael 182]

"Rick Glasser" > wrote in message
.. .
> On Wed, 18 Feb 2004 20:32:22 +0000, Michael 182 wrote:
>
> > What is the reasoning behind the required course reversal in many
> > approaches? It's hard to believe that I will be safer flying the
racetrack
> > and then the approach to the runway than simply flying to the IAF and
> > proceeding inbound - especially with GPS guidance. I have no problem
flying
> > the full published course, done it many times, I'm just curious why they
are
> > designed that way.
> >
> > Michael
>
> It is also to allow you to get "established" and stabilized on the inbound
> course prior to the FAF, especially where the IAF and FAF are the same.
> If you just turned inbound at the fix, precious distance would be wasted
> while still getting established and technically you should not be
> descending until established.


I know this is what is often written but I think this only argues for an
optional run around the racetrack, not a mandatory turn, or an instruction
on the approach that requires the course reversal if crossing the IAF above
XX altitude. Does that make sense?

Michael

[Andrew Sarangan]

When a single fix doubles as the IAF and the FAF, a PT will be
required. The reason is, an aircraft could be approaching the IAF from
any direction, and you need to maneuver in order to get established on
the final approach course prior to reaching the FAF. When two fixes
are available for an approach, that is when you are likely to find a
NoPT. GPS approaches rarely have PT because you can place a fix almost
anywhere.





"Michael 182" > wrote in message news:<qZPYb.7436$Xp.59196@attbi_s54>...
> What is the reasoning behind the required course reversal in many
> approaches? It's hard to believe that I will be safer flying the racetrack
> and then the approach to the runway than simply flying to the IAF and
> proceeding inbound - especially with GPS guidance. I have no problem flying
> the full published course, done it many times, I'm just curious why they are
> designed that way.
>
> Michael

[Ron Rosenfeld]

On Wed, 18 Feb 2004 20:32:22 GMT, "Michael 182"
> wrote:

>What is the reasoning behind the required course reversal in many
>approaches? It's hard to believe that I will be safer flying the racetrack
>and then the approach to the runway than simply flying to the IAF and
>proceeding inbound - especially with GPS guidance. I have no problem flying
>the full published course, done it many times, I'm just curious why they are
>designed that way.
>
>Michael
>

Michael,

Others have given you some good answers. However, the reasoning often
depends on the particular approach. So it would be useful if you could
post a reference to a procedure about which you have a question.




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

[[email protected]]

They are for altitude loss, and proper alignment when the course change exceeds
120 degrees (the limit is 90 degrees unless the intermediate segment is
lengthened to accommodate a course change of 91 to 120 degrees.)

Michael 182 wrote:

> What is the reasoning behind the required course reversal in many
> approaches? It's hard to believe that I will be safer flying the racetrack
> and then the approach to the runway than simply flying to the IAF and
> proceeding inbound - especially with GPS guidance. I have no problem flying
> the full published course, done it many times, I'm just curious why they are
> designed that way.
>
> Michael

[Michael 182]

Well, as an example, the BJC ILS 29R. In this case ALIKE is both the IAF and
the FF. Clearly if you are coming in from the west or southeast quadrants,
the course reversal is needed to lose altitude, as John pointed out. Also,
as Andrew pointed out, even if the approach was in Kansas, you migt be
approaching on a 090 heading to a final approach course of 293, and hence
the course reversal makes sense. I guess my question is why not have a
conditional, say if approaching with heading 270 - 330 at altitude of 7300,
no PT required.

I'm not trying to be arugmentative - I just think the procedure turn, in
IMC, may cause more danger than it allieves. On the other hand the
conditional may complicate the instruction - conditionals always provide
more opportunity for error.

Michael


"Ron Rosenfeld" > wrote in message
...
> On Wed, 18 Feb 2004 20:32:22 GMT, "Michael 182"
> > wrote:
>
> >What is the reasoning behind the required course reversal in many
> >approaches? It's hard to believe that I will be safer flying the
racetrack
> >and then the approach to the runway than simply flying to the IAF and
> >proceeding inbound - especially with GPS guidance. I have no problem
flying
> >the full published course, done it many times, I'm just curious why they
are
> >designed that way.
> >
> >Michael
> >
>
> Michael,
>
> Others have given you some good answers. However, the reasoning often
> depends on the particular approach. So it would be useful if you could
> post a reference to a procedure about which you have a question.
>
>
>
>
> Ron (EPM) (N5843Q, Mooney M20E) (CP, ASEL, ASES, IA)

[Bob Gardner]

Why would a maneuver in protected airspace, sterilized against other IFR
(and VFR talking to ATC) airplanes be dangerous?

Bob Gardner

"Michael 182" > wrote in message
news:4E5Zb.78441$uV3.535345@attbi_s51...
> Well, as an example, the BJC ILS 29R. In this case ALIKE is both the IAF
and
> the FF. Clearly if you are coming in from the west or southeast quadrants,
> the course reversal is needed to lose altitude, as John pointed out.
Also,
> as Andrew pointed out, even if the approach was in Kansas, you migt be
> approaching on a 090 heading to a final approach course of 293, and hence
> the course reversal makes sense. I guess my question is why not have a
> conditional, say if approaching with heading 270 - 330 at altitude of
7300,
> no PT required.
>
> I'm not trying to be arugmentative - I just think the procedure turn, in
> IMC, may cause more danger than it allieves. On the other hand the
> conditional may complicate the instruction - conditionals always provide
> more opportunity for error.
>
> Michael
>
>
> "Ron Rosenfeld" > wrote in message
> ...
> > On Wed, 18 Feb 2004 20:32:22 GMT, "Michael 182"
> > > wrote:
> >
> > >What is the reasoning behind the required course reversal in many
> > >approaches? It's hard to believe that I will be safer flying the
> racetrack
> > >and then the approach to the runway than simply flying to the IAF and
> > >proceeding inbound - especially with GPS guidance. I have no problem
> flying
> > >the full published course, done it many times, I'm just curious why
they
> are
> > >designed that way.
> > >
> > >Michael
> > >
> >
> > Michael,
> >
> > Others have given you some good answers. However, the reasoning often
> > depends on the particular approach. So it would be useful if you could
> > post a reference to a procedure about which you have a question.
> >
> >
> >
> >
> > Ron (EPM) (N5843Q, Mooney M20E) (CP, ASEL, ASES, IA)
>
>

[Michael 182]

I think I said " I just think the procedure turn, in IMC, may cause more
danger than it allieves". I don't think the turn is dangerous per se, but an
approach directly to the FF and inbound, with no dramatic changes in
altitude and direction, seems less dangerous than the same approach with the
addition of a run around the racetrack.

Michael



"Bob Gardner" > wrote in message
news:jK6Zb.359414$na.536935@attbi_s04...
> Why would a maneuver in protected airspace, sterilized against other IFR
> (and VFR talking to ATC) airplanes be dangerous?
>
> Bob Gardner

[Michael]

"Michael 182" > wrote
> What is the reasoning behind the required course reversal in many
> approaches? It's hard to believe that I will be safer flying the racetrack
> and then the approach to the runway than simply flying to the IAF and
> proceeding inbound - especially with GPS guidance. I have no problem flying
> the full published course, done it many times, I'm just curious why they are
> designed that way.

They are designed that way for the least proficient pilot (the one who
just squeaked through his instrument rating ride) with the minimum
equipment (no GPS, certainly).

In most (maybe all) cases, a proficient pilot with GPS guidance can
safely proceed to the FAF, lead his turn onto the FAC using the GPS,
and sort out the exact course alignment while descending on the GS or
to MDA. In fact, many freight dogs do it all the time when not in
RADAR contact, to save time. The only time a course reversal is ever
really necessary is when the transition segment has a very high
minimum altitude (due to terrain) and you just can't get down in time
without shock cooling your engine(s).

On the other hand, if you must fly a crappy non-precision approach to
mins when you haven't flown IFR in weeks, especially partial panel and
without GPS guidance, you will want to be solidly established on the
FAC, with crosswind correction in place, because otherwise the
approach will eat your lunch as you attempt to turn onto final, get
the descent going, blow through the final, correct the other way...
well, just try it sometime and you will see what I mean.

Of course the course reversal ought to be optional - a pilot ought to
know what his limitations are and if he feels that he doesn't need the
procedure turn, then he shouldn't have to make one. However, in
practice it's already that way. If you are in RADAR contact, you will
generally get vectors to final anyway. If you don't, controllers are
generally all too happy to clear you for the approach without course
reversal. Requested it a couple of times myself, always got it. Is
it legal? Who knows. One thing is for sure, nobody is going to
report it so nobody is getting busted. And of course if you're not in
RADAR contact, you can do whatever you want, nobody is watching.

Michael

[Michael 182]

Good answer - thanks.

Michael

"Michael" > wrote in message
om...
> "Michael 182" > wrote
> > What is the reasoning behind the required course reversal in many
> > approaches? It's hard to believe that I will be safer flying the
racetrack
> > and then the approach to the runway than simply flying to the IAF and
> > proceeding inbound - especially with GPS guidance. I have no problem
flying
> > the full published course, done it many times, I'm just curious why they
are
> > designed that way.
>
> They are designed that way for the least proficient pilot (the one who
> just squeaked through his instrument rating ride) with the minimum
> equipment (no GPS, certainly).
>
> In most (maybe all) cases, a proficient pilot with GPS guidance can
> safely proceed to the FAF, lead his turn onto the FAC using the GPS,
> and sort out the exact course alignment while descending on the GS or
> to MDA. In fact, many freight dogs do it all the time when not in
> RADAR contact, to save time. The only time a course reversal is ever
> really necessary is when the transition segment has a very high
> minimum altitude (due to terrain) and you just can't get down in time
> without shock cooling your engine(s).
>
> On the other hand, if you must fly a crappy non-precision approach to
> mins when you haven't flown IFR in weeks, especially partial panel and
> without GPS guidance, you will want to be solidly established on the
> FAC, with crosswind correction in place, because otherwise the
> approach will eat your lunch as you attempt to turn onto final, get
> the descent going, blow through the final, correct the other way...
> well, just try it sometime and you will see what I mean.
>
> Of course the course reversal ought to be optional - a pilot ought to
> know what his limitations are and if he feels that he doesn't need the
> procedure turn, then he shouldn't have to make one. However, in
> practice it's already that way. If you are in RADAR contact, you will
> generally get vectors to final anyway. If you don't, controllers are
> generally all too happy to clear you for the approach without course
> reversal. Requested it a couple of times myself, always got it. Is
> it legal? Who knows. One thing is for sure, nobody is going to
> report it so nobody is getting busted. And of course if you're not in
> RADAR contact, you can do whatever you want, nobody is watching.
>
> Michael

[Ron Rosenfeld]

On Thu, 19 Feb 2004 16:38:24 GMT, "Michael 182"
> wrote:

>Well, as an example, the BJC ILS 29R. In this case ALIKE is both the IAF and
>the FF. Clearly if you are coming in from the west or southeast quadrants,
>the course reversal is needed to lose altitude, as John pointed out. Also,
>as Andrew pointed out, even if the approach was in Kansas, you migt be
>approaching on a 090 heading to a final approach course of 293, and hence
>the course reversal makes sense. I guess my question is why not have a
>conditional, say if approaching with heading 270 - 330 at altitude of 7300,
>no PT required.

Now you have to ask yourself how you would navigate to an area South or
East of ALIKE at an altitude of 7300'? I'm having to look at a NACO chart,
and I'm used to Jepps. But it seems that there is no airway leading to
ALIKE. And the MSA for that area is 10500'.

If ATC can give you "vectors to final" in that area, then you would not
have to do the course reversal (and can't do it without permission). But
absent radar vectors, I don't see a charted way to get to ALIKE at an
altitude low enough to avoid the course reversal.


>
>I'm not trying to be arugmentative - I just think the procedure turn, in
>IMC, may cause more danger than it allieves. On the other hand the
>conditional may complicate the instruction - conditionals always provide
>more opportunity for error.
>

If you feel that procedure turns cause danger, you probably need to
practice them. They should be second nature.


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

[[email protected]]

Michael 182 wrote:

> Good answer - thanks.

Good answer, or the answer you wanted to hear?

[Michael 182]

"Ron Rosenfeld" > wrote in message
...
> On Thu, 19 Feb 2004 16:38:24 GMT, "Michael 182"
> > wrote:
>

> Now you have to ask yourself how you would navigate to an area South or
> East of ALIKE at an altitude of 7300'? I'm having to look at a NACO
chart,
> and I'm used to Jepps. But it seems that there is no airway leading to
> ALIKE. And the MSA for that area is 10500'.

MSA to the NE is 7300. Navigation by GPS.

>
> If ATC can give you "vectors to final" in that area, then you would not
> have to do the course reversal (and can't do it without permission). But
> absent radar vectors, I don't see a charted way to get to ALIKE at an
> altitude low enough to avoid the course reversal.
>
>
> If you feel that procedure turns cause danger, you probably need to
> practice them. They should be second nature.

Hard to argue I need more practice since I live in Colorado where we get
very little actual and I only fly 100-150 hours or so a year. In fact, I
just hired a CFII for some practice (and an IPC) the other day. No argument
that more practice and currency would make me a better pilot. Regardless, my
point was not that the PT was dangerous, but relative to an almost straight
in approach just added some incremental danger, since there is more time
spent maneuvering in IMC at a reasonable low altitude.


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

[Michael 182]

A good answer, with information that was interesting to me. The regs are
clear, and I'm not looking to circumvent them. My first post on this topic
made it clear I was interested in reasoning, not just regulatory fact.

MIchael


> wrote in message ...
>
>
> Michael 182 wrote:
>
> > Good answer - thanks.
>
> Good answer, or the answer you wanted to hear?
>

[Ron Rosenfeld]

On Fri, 20 Feb 2004 03:04:53 GMT, "Michael 182"
> wrote:

>MSA to the NE is 7300. Navigation by GPS.


Hmmm. According to the NACO chart I downloaded from AOPA, it looks as if
the MSA is centered on BJC (VORTAC). So if you are NE of ALIKE, and south
of the BJC 090° radial, you would be in the 10500 segment.

If you have a Jepp chart that shows the MSA centered on ALIKE, we need to
report the discrepancy.


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

[Michael 182]

You're right. My mistake.

Michael

"Ron Rosenfeld" > wrote in message
...
> On Fri, 20 Feb 2004 03:04:53 GMT, "Michael 182"
> > wrote:
>
> >MSA to the NE is 7300. Navigation by GPS.
>
>
> Hmmm. According to the NACO chart I downloaded from AOPA, it looks as if
> the MSA is centered on BJC (VORTAC). So if you are NE of ALIKE, and south
> of the BJC 090° radial, you would be in the 10500 segment.
>
> If you have a Jepp chart that shows the MSA centered on ALIKE, we need to
> report the discrepancy.
>
>
> Ron (EPM) (N5843Q, Mooney M20E) (CP, ASEL, ASES, IA)

[Bob Gardner]

MSA is not an operational altitude...it is for emergency use only. Read
5-4-5 AIM.

Bob Gardner

"Michael 182" > wrote in message
news:pPeZb.82854$uV3.542041@attbi_s51...
>
> "Ron Rosenfeld" > wrote in message
> ...
> > On Thu, 19 Feb 2004 16:38:24 GMT, "Michael 182"
> > > wrote:
> >
>
> > Now you have to ask yourself how you would navigate to an area South or
> > East of ALIKE at an altitude of 7300'? I'm having to look at a NACO
> chart,
> > and I'm used to Jepps. But it seems that there is no airway leading to
> > ALIKE. And the MSA for that area is 10500'.
>
> MSA to the NE is 7300. Navigation by GPS.
>
> >
> > If ATC can give you "vectors to final" in that area, then you would not
> > have to do the course reversal (and can't do it without permission).
But
> > absent radar vectors, I don't see a charted way to get to ALIKE at an
> > altitude low enough to avoid the course reversal.
> >
> >
> > If you feel that procedure turns cause danger, you probably need to
> > practice them. They should be second nature.
>
> Hard to argue I need more practice since I live in Colorado where we get
> very little actual and I only fly 100-150 hours or so a year. In fact, I
> just hired a CFII for some practice (and an IPC) the other day. No
argument
> that more practice and currency would make me a better pilot. Regardless,
my
> point was not that the PT was dangerous, but relative to an almost
straight
> in approach just added some incremental danger, since there is more time
> spent maneuvering in IMC at a reasonable low altitude.
>
>
> >
> > Ron (EPM) (N5843Q, Mooney M20E) (CP, ASEL, ASES, IA)
>
>

[Ron Rosenfeld]

On Sat, 21 Feb 2004 22:40:09 GMT, "Bob Gardner" > wrote:

>MSA is not an operational altitude...it is for emergency use only. Read
>5-4-5 AIM.

Agreed.

However, the context of this discussion seems to be pilot-nav random
routing and the reason for a procedure turn at this particular approach.
It is not a vectors-to-final routing where ATC may assign an altitude.

Are you of the opinion that the IFR charts suggest that when on a random
route and NE of ALIKE (but south of the BJC 090 radial) that 7300 is a
perfectly OK altitude to use?

My teaching has been that when not on a "solid black line" or receiving
radar vectors from ATC, to not go below the MSA, OROCA, etc., for that
area.


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

[Michael]

Ron Rosenfeld > wrote
> Are you of the opinion that the IFR charts suggest that when on a random
> route and NE of ALIKE (but south of the BJC 090 radial) that 7300 is a
> perfectly OK altitude to use?
>
> My teaching has been that when not on a "solid black line" or receiving
> radar vectors from ATC, to not go below the MSA, OROCA, etc., for that
> area.

The relevant regulation is 91.177 - other than when on approach, 1000
ft above any obstacles within 4 nm of course, or 2000 in designated
mountainous areas. If you meet that, you're complying with 91.177.
The question is how to best comply with this?

On a solid black line, the altitude is published. On vectors, it's
ATC's responsibility. On a random route, it's your responsibility -
sort of. It is relatively common (at least in my neck of the woods)
to have approaches where the FAC is not depicted on the controller's
scope. In this situation, RADAR services are available, but vectors
to final are not. It's fairly common (in my experience) to get a
clearance direct to the IAF (NOT a vector) at an altitude lower than
anything published - OROCA, MSA, or even the published minimum
altitude for crossing the FAF. Clearly the controller is using his
MVA for this. Are you suggesting that accepting such a clearance is
improper?

Even without RADAR services, it's not all that clearcut. Certainly if
you maintain OROCA or MSA, you're complying, and in many cases this is
the way to go. However, this is often not practical. For example, in
my next of the woods there are tethered balloons going to 15000 ft,
and that makes OROCA just over 16000 for the sector. This would make
direct routings impossible for anyone without turbos. In reality, the
minimum altitudes for direct routings in most of that sector are in
the 2000-4000 range.

I've seen a similar situation apply to the MSA, where an entire sector
had an MSA about 1500 ft higher than it would have been had it not
been for ONE tower, about 23 nm away from the fix. I have to believe
that in mountainous terrain, this is even more common, since airports
tend to be in valleys.

Under Part 91, there is really no defined requirement for where the
data you use to comply with 91.177 should come from. However, I have
to believe that any FAA-recognized chart is fair game. I have no idea
if 7300 is OK in the area you describe, because I have not seen the
relevant VFR chart. It might be. If the obstructions that make the
MSA in the sector 10,500 are 20 miles away, and the local terrain is
much lower, then maybe it is. However, with only the infomation on
the approach plate, I sure wouldn't try it.

Michael

[Ron Rosenfeld]

On 25 Feb 2004 07:40:02 -0800, (Michael) wrote:

>Ron Rosenfeld > wrote
>> Are you of the opinion that the IFR charts suggest that when on a random
>> route and NE of ALIKE (but south of the BJC 090 radial) that 7300 is a
>> perfectly OK altitude to use?
>>
>> My teaching has been that when not on a "solid black line" or receiving
>> radar vectors from ATC, to not go below the MSA, OROCA, etc., for that
>> area.
>
>The relevant regulation is 91.177 - other than when on approach, 1000
>ft above any obstacles within 4 nm of course, or 2000 in designated
>mountainous areas. If you meet that, you're complying with 91.177.
>The question is how to best comply with this?
>
>On a solid black line, the altitude is published. On vectors, it's
>ATC's responsibility. On a random route, it's your responsibility -
>sort of. It is relatively common (at least in my neck of the woods)
>to have approaches where the FAC is not depicted on the controller's
>scope. In this situation, RADAR services are available, but vectors
>to final are not. It's fairly common (in my experience) to get a
>clearance direct to the IAF (NOT a vector) at an altitude lower than
>anything published - OROCA, MSA, or even the published minimum
>altitude for crossing the FAF. Clearly the controller is using his
>MVA for this. Are you suggesting that accepting such a clearance is
>improper?

No, and I thought I was clear about that. If the controller is providing
vectors, they are responsible for ensuring you are at an acceptable
altitude. The procedure is (should be) to instruct you to maintain an
altitude that will ensure obstacle clearance until you are established on a
segment of a published route or instrument approach.

As a matter of fact, radar is not even necessary to receive that sort of
service. I will usually be cleared for approach to my local airport, with
a restriction to maintain a specific altitude until crossing the IAF. And
radar services are terminated well before my arrival (usually about 25+
miles out). AAMOF, we don't even have radio services below about 4000 ft.

>
>Even without RADAR services, it's not all that clearcut. Certainly if
>you maintain OROCA or MSA, you're complying, and in many cases this is
>the way to go. However, this is often not practical. For example, in
>my next of the woods there are tethered balloons going to 15000 ft,
>and that makes OROCA just over 16000 for the sector. This would make
>direct routings impossible for anyone without turbos. In reality, the
>minimum altitudes for direct routings in most of that sector are in
>the 2000-4000 range.
>
>I've seen a similar situation apply to the MSA, where an entire sector
>had an MSA about 1500 ft higher than it would have been had it not
>been for ONE tower, about 23 nm away from the fix. I have to believe
>that in mountainous terrain, this is even more common, since airports
>tend to be in valleys.
>
>Under Part 91, there is really no defined requirement for where the
>data you use to comply with 91.177 should come from. However, I have
>to believe that any FAA-recognized chart is fair game.

I agree with what you have said. However, the 91.177 1000/2000/4 altitudes
apply only if there is no applicable minimum altitude prescribed in Part 95
or 97. It is not clear to me whether the MSA, even though it is prescribed
in Part 97, is an "applicable minimum altitude". If so, it may be even
lower than the 91.177 minimums as it only provides 1000' of clearance.

However, given that the area is controlled airspace, the likelihood is that
an a/c arriving from the NE segment will be cleared for the approach by
ATC. I'm not familiar with exactly what goes on in the BJC area, but I'd
guess that the pilot will either receive vector to final, in which case the
issue of course reversal is moot; or he will receive an altitude to
maintain until crossing ALIKE and will be obliged to execute the course
reversal procedure. Looking at some of the airways in the vicinity, it
seems the MEA/MOCA is higher than 7200'. And one would have to be down to
7200 outside of ALIKE in order to intercept the Glide Slope from below.


> I have no idea
>if 7300 is OK in the area you describe, because I have not seen the
>relevant VFR chart. It might be. If the obstructions that make the
>MSA in the sector 10,500 are 20 miles away, and the local terrain is
>much lower, then maybe it is. However, with only the infomation on
>the approach plate, I sure wouldn't try it.

My point, exactly.


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

[Michael]

Ron Rosenfeld > wrote
> The procedure is (should be) to instruct you to maintain an
> altitude that will ensure obstacle clearance until you are established on a
> segment of a published route or instrument approach.

Right. My point is that you're not on vectors, you're not on a solid
black line, you're below OROCA/MSA, and you're still OK.

> I agree with what you have said. However, the 91.177 1000/2000/4 altitudes
> apply only if there is no applicable minimum altitude prescribed in Part 95
> or 97. It is not clear to me whether the MSA, even though it is prescribed
> in Part 97, is an "applicable minimum altitude".

Well, I think that was the point - it's an emergency altitude only,
and thus not an applicable minimum altitude. Ref 97.3(l) MSA means
minimum safe altitude, an emergency altitude expressed in feet above
mean sea level, which provides 1,000 feet clearance over all
obstructions in that sector within 25 miles of the facility on which
the procedure is based (LOM in ILS procedures).

> However, given that the area is controlled airspace, the likelihood is that
> an a/c arriving from the NE segment will be cleared for the approach by
> ATC. I'm not familiar with exactly what goes on in the BJC area, but I'd
> guess that the pilot will either receive vector to final, in which case the
> issue of course reversal is moot; or he will receive an altitude to
> maintain until crossing ALIKE and will be obliged to execute the course
> reversal procedure. Looking at some of the airways in the vicinity, it
> seems the MEA/MOCA is higher than 7200'. And one would have to be down to
> 7200 outside of ALIKE in order to intercept the Glide Slope from below.

The point is that without access to the MVA charts, we don't know what
altitude he will be cleared to. And the whole point of the thread is
that if he is cleared to 7200 or less and approaches ALIKE from a
reasonable direction, the procedure turn is basically a waste of time
but legally he is still required to execute it.

Given that on RADAR vectors we are routinely set up for a 30 degree
intercept right at the FAF, I would think that it's reasonable to have
aircraft approaching at the correct altitude and within 30 degrees of
the FAC skip the procedure turn as a general rule. I have actually
seen approaches which exempt a certain arc from PT requirements - HUM
VOR RWY 12 is one example I've actually
shot.(http://www.myairplane.com/databases/approach/SouthCentral/HUM_vr12.pdf)
In my opinion, something like this ought to be a general rule, rather
than a specific. Those who do not feel like they can get established
can always request the course reversal.

Michael

[Michael 182]

"Michael" > wrote in message
om...
> Given that on RADAR vectors we are routinely set up for a 30 degree
> intercept right at the FAF, I would think that it's reasonable to have
> aircraft approaching at the correct altitude and within 30 degrees of
> the FAC skip the procedure turn as a general rule. I have actually
> seen approaches which exempt a certain arc from PT requirements - HUM
> VOR RWY 12 is one example I've actually
>
shot.(http://www.myairplane.com/databases/approach/SouthCentral/HUM_vr12.pdf
)
> In my opinion, something like this ought to be a general rule, rather
> than a specific. Those who do not feel like they can get established
> can always request the course reversal.
>
> Michael

Thanks for the approach reference. This is exactly what I was talking about
when I started the thread.

Michael

[Ron Rosenfeld]

On 26 Feb 2004 06:59:12 -0800, (Michael) wrote:

>Given that on RADAR vectors we are routinely set up for a 30 degree
>intercept right at the FAF, I would think that it's reasonable to have
>aircraft approaching at the correct altitude and within 30 degrees of
>the FAC skip the procedure turn as a general rule.

I would disagree with you that that should be a general rule.

There is a very specific rule that says if you are getting vectors to
final, than you don't do a course reversal (without notifying ATC). In
order for ATC to safely give you VTF, certain requirements must be met at
their end.

And you should NOT be getting a turn on AT the FAF unless you have
specifically requested it. Furthermore, (and one of the controller's may
correct me here), the interception angle should not be more than 20° unless
you are a few miles (?2?) outside of the approach gate, which itself will
be outside of the FAF.

If ATC is giving you a 30° intercept at the FAF without you requesting it,
I believe they are acting contrary to their manual, and engaging in a
potentially dangerous practice.


> I have actually
> seen approaches which exempt a certain arc from PT requirements

The one you cite is a LOT different from the circumstance we are
discussing. The approach you cite is NoPT for arrivals at the IAF if you
are ON AIRWAYS (V198 or V552) leading to an IAF (TBD VORTAC) which is
separated from the FAF by a five mile intermediate segment.

The procedure you are proposing at BJC has you arriving at ALIKE (which is
a collocated IAF/FAF) and essentially using it as an FAF. Skipping the PT
in that circumstance is not something I feel is safe "as a general rule".


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

[Michael]

Ron Rosenfeld > wrote
> If ATC is giving you a 30° intercept at the FAF without you requesting it,
> I believe they are acting contrary to their manual

This may well be, but I find it's more the norm than the exception.

> and engaging in a potentially dangerous practice.

Maybe I'm just used to it, but it really doesn't seem to be. Now when
they give me a 60 degree intercept inside the FAF...

Michael