Reasoning behind course reversal

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" 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.

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.

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
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"Rick Glasser" wrote in message
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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

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

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)

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

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)

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)