Procedure turn required?

The AIM is not regulatory, but it is directive.

The regulatory source is the Part 97 document for any particular IAP. If there
is a course reversal initial approach segment and NoPT is not on a segment
leading to the course reversal segment then by inference the course reversal is
required.

In cases where alignment seems to make it unnecessary it may be an issue of
descent gradient. It other cases, it may be poor procedure design and pilots
have a duty to provide feedback to the FAA in such cases.

If you check through the minutes of previous FAA Aeronautical Charting Forums
you can find that the AIM language cited was done in a couple of steps to try to
make clear what is implied by the individual amendment to Part 97 for any
particular SIAP.

The reason the course reversal is required in the cited case at KFUL is because
going straight in from V-64 requires a course change entering the final approach
segment that well exceeds the maximum course change at the FAF of 30 degrees
permitted for VOR IAPs.

Like it or not that is the criteria. Keep in mind that TERPs is simplistic
criteria in the sense that it tries to make one size fit all in most aspects of
IAP construction.

Peter Duniho wrote:

"Yossarian" wrote in message
7.142...
AIM 5-4-9 a. The procedure turn or hold in lieu of procedure turn is a
required maneuver.

I'm going to have to equivocate on the phrase "is a required maneuver".
You'll note that the very first sentence reads (in part) "A procedure turn
is the maneuver prescribed when it is necessary to perform a course
reversal..."

The AIM is, of course, not regulatory. So if it claims that the procedure
turn is a required maneuver, it must be referring to some other regulation
somewhere. Of course, the AIM doesn't actually provide a cross-reference,
so we don't know what regulation they have in mind.

I'm going to go out on a limb here and suggest that the "is a required
maneuver" phrase applies only when "it is necessary to perform a course
reversal". IMHO, any other interpretation is absurd. They are specifically
telling you the procedure turn exists for the sole purpose of reversing
course; why would it be required to fly the procedure turn when you don't
need to reverse course?

Executing a procedure turn in the example you give requires more
maneuvering, more time, and provides no real safety improvement (and in
fact, could lead to a pilot inadvertently leaving the protected airspace,
and/or flying below minimum safe altitudes for the approach and surrounding
area).

Now, all that said, I think I've already implied I'm not an expert in this
area. I certainly don't KNOW that I'm right. But I'm definitely not
convinced I'm wrong either.

[...] I'm betting not many
people fly the procedure turn coming in from WILMA.

true on that last sentence, but it's because you always get vectors.

I will further bet that's not the ENTIRE reason.

Where's Wally when you need him?

Actually, he might not be as helpful (at least, to me) as I might have
thought. Here's an interesting article that supports your interpretation of
the rules:
http://cf.alpa.org/internet/alp/2000/jansafety.htm
However, IMHO it's an obviously absurd way to interpret the rules. It
doesn't address your example directly, since the inbound course is nearly
aligned with the final approach course. But it seems patently obvious to me
that flying the entire procedure turn in this case is just plain wrong; it
achieves nothing except to waste time and put the airplane farther away from
a proper approach course.

Roberts is, as the article shows, a firm believer that without radar vectors
and/or other criteria mentioned in the AIM, the procedure turn is mandatory.
The justification appears to be that no matter how closely aligned with the
final approach course you are, if you're not EXACTLY aligned with it, you
have to turn around and "try again".

My understanding is that, if ever there was an expert, Roberts is it. But
it's still unclear to me where his interpretation comes from. It also still
seems to fly in the face of sensibility.

Another well-respected aviation educator and writer, Gene Whitt, suggests
that it is the pilot's discretion to fly the procedure turn or not (though,
he also has no references). From his web page:
http://www.whittsflying.com/Page7.38...Procedures.htm

If ATC does not specifically state that you will be given
radar vectors, you as PIC can decide if a procedure turn
is required.

Note that I am not suggesting that straight-in always implies no need to fly
the procedure turn. As Jose noted, there may also be an altitude issue.
I'm simply talking about the example you provided, in which the transition
altitude is already low enough to allow for entry over the FAF at a normal
approach inbound altitude, and where the maneuvering required in order to
complete the procedure turn is at least as complex (and thus potentially
dangerous) as that required to simply proceed inbound on the approach from
the transition route.

Pete

wrote in message ...
[...]
The reason the course reversal is required in the cited case at KFUL is
because
going straight in from V-64 requires a course change entering the final
approach
segment that well exceeds the maximum course change at the FAF of 30
degrees
permitted for VOR IAPs.

A procedure turn requires a course change of over 130 degrees (including
getting back onto the outbound course). And then of 180 degrees. You can
fly the transition at the same altitude allowed for the procedure turn.

How is the procedure turn better?

Like it or not that is the criteria. Keep in mind that TERPs is
simplistic
criteria in the sense that it tries to make one size fit all in most
aspects of
IAP construction.

Well, I can agree with that.

From a practical point of view, however...

It seems likely that when radar coverage is available, vectors will be
given. This allows no procedure turn to be flown. If radar coverage is not
available, how is anyone going to know if you've flown the procedure turn?

I would think that from an enforcement point of view, the cases where a
procedure turn is theoretically required, but where the pilot could ever be
cited for not flying one, are pretty far and few between. From a safety
point of view, not flying the procedure turn appears to be the superior
approach, at least in this case.

Pete

On Sat, 4 Jun 2005 11:13:47 -0700, "Peter Duniho"
wrote:

It seems likely that when radar coverage is available, vectors will be
given. This allows no procedure turn to be flown. If radar coverage is not
available, how is anyone going to know if you've flown the procedure turn?

Anyone who listens to the tapes, assuming radio coverage? At least
around here whenever I'm flying a full procedure ATC always requests
"report procedure turn inbound".

A procedure turn requires a course change of over 130 degrees (including
getting back onto the outbound course). And then of 180 degrees. You can
fly the transition at the same altitude allowed for the procedure turn.

How is the procedure turn better?

All the maneuvering is done prior to the FAF, and prior to descent.

Jose
--
The price of freedom is... well... freedom.
for Email, make the obvious change in the address.

"Jose" wrote in message
. com...
How is the procedure turn better?

All the maneuvering is done prior to the FAF, and prior to descent.

Offset by the significant increase in the amount and difficulty of
maneuvering required. I agree you've shown it to be different. I don't see
how it's better.

Pete

How is the procedure turn better?
All the maneuvering is done prior to the FAF, and prior to descent.
Offset by the significant increase in the amount and difficulty of
maneuvering required. I agree you've shown it to be different. I don't see
how it's better.

It's better because it's safer. There is no real increased difficulty -
one standard rate turn is like another, and making a longer turn is no
harder (unless you fall asleep during the turn, then the landing is much
harder!).

When you make the turns used for the full procedure, you end up right
where you are supposed to be. But if you make a turn to final that
takes fifty degrees, you will =not= be on the FAC. You'll have lagged,
and have to squirrel yourself back to be on course. You're also
approaching the MAP and descending.

This is harder.

Or you can anticipate the turn. How much? Well, (fudge fudge fudge)...
This is harder.

Maybe not harder enough to be =unsafe=, but harder enough that, combined
with proximity (to the ground and the airport) it is less safe.

Jose
--
The price of freedom is... well... freedom.
for Email, make the obvious change in the address.

"Jose" wrote in message
om...
It's better because it's safer.

You have not demonstrated that. To demonstrate an improvement in safety,
you need to compare a statistically significant number of samples using both
methods, and then look at the resulting accident rates for each method.

You certainly can't claim that it's "obviously safer". That is, it's not
true that "one standard rate turn is like another". Any maneuvering runs
the risk of causing an accident, and the more time spent maneuvering, the
greater the exposure to that risk (this is no different from saying "any
flight runs the risk of causing an accident, and the more time spent flying,
the greater the exposure to that risk").

As far as the difference in difficulty, one can debate that as well.
Inasmuch as a pilot ought to be maintaining a mental picture of his position
while flying by instruments, an extended turn away from one's destination
certainly could be more difficult than a prompt turn toward one's
destination. Furthermore, the right-310 turn is just one option of many,
and several of the other options involve multiple turns in multiple
directions. Increased complexity implies increased difficulty IMHO.

Whether this increase in complexity offsets the potential increase in
complexity of turning directly 50 degrees onto the final approach course,
has not been established. I suggest it does, you suggest it doesn't, and
neither of us has any justification for making such statements, other than
our own intuition.

[...]
When you make the turns used for the full procedure, you end up right
where you are supposed to be.

You might be, if you do it right. There's no guarantee though. Even if
done properly, you are still "allowed" a significant margin of error.

But if you make a turn to final that takes fifty degrees, you will =not=
be on the FAC.

If you simply intercept the approach course, how would you not wind up on
the approach course?

You'll have lagged, and have to squirrel yourself back to be on course.
You're also approaching the MAP and descending.

This is harder.

It is different. I see it as being FAR from a foregone conclusion that it
is harder.

Or you can anticipate the turn. How much? Well, (fudge fudge fudge)...
This is harder.

Maybe not harder enough to be =unsafe=, but harder enough that, combined
with proximity (to the ground and the airport) it is less safe.

Well, we're back to that. You haven't demonstrated "less safe". You simply
asserted it. There's a difference.

Pete

You have not demonstrated that [it's safer]. To demonstrate an improvement in safety,
you need to compare a statistically significant number of samples using both
methods, and then look at the resulting accident rates for each method.

I'm not going to do that. Neither are you going to do the same for your
contention that it's best to simply turn final, irrespective of what the
regulations (including the opinion of FAA legal council) state.

So we are back to using reasoning to infer safety from (personal and
shared) experience.

Any maneuvering runs
the risk of causing an accident, and the more time spent maneuvering, the
greater the exposure to that risk

True. However, turns happen all the time. I'm not convinced that a
standard rate turn is so risky that an extra hundred degrees or two
makes a significant difference, all other things being equal.

That said, all other things are =not= equal. "My" turns are done at
altitude, flying towards protected airspace, in an area that has been
certified for such turns. "Your" turns are done flying towards the
final approach fix, at the commencement of a descent, off from the final
approach course, and in an area that has been proscribed by the FAA for
such turns (which means in this case that the terrain and airspace has
not been checked and approved for these turns).

It is those conditions that I contend make "your" turns less safe.

an extended turn away from one's destination
certainly could be more difficult than a prompt turn toward one's
destination.

I'm not sure I follow this reasoning, and I don't agree with what I
think you mean. A pilot who's on top of things should have no problem
with either turn (in terms of situational awareness) and one that's a
little behind could use the extra time flying away and then back,
establishing themselves on the FAC long before the FAF.

I suggest it does, you suggest it doesn't, and
neither of us has any justification for making such statements, other than
our own intuition.

Well, we have our own flight experience, and I assume that much of it is
similar.

If you simply intercept the approach course, how would you not wind up on
the approach course?

This paraphrases as "if you succeed, how could you have failed"? A
course interception involves some S-turning or anticipation, iow some
slop. The shallower the intercept, the less slop. Intercepting the FAC
at low altitude is a critical enough maneuver that slop should be
minimized. You need to be dead on. (fsvo "dead" However, turning
away from the FAC and =not= descending would allow slop to be safer.
The FAA has chosen 30 degrees as the amount of turn which balances slop
one way with slop the other way. I don't know whether the number
"should" be 30 degrees, 50 degrees, or 10 degrees, but I suspect the
TERPS designers have some data to back themselves up, and I'll trust
their design.

You haven't demonstrated "less safe". You simply
asserted it. There's a difference.

I have asserted it and given my reasoning. Reasoning isn't proof, and
isn't intended to be.

Jose
--
The price of freedom is... well... freedom.
for Email, make the obvious change in the address.