Oct 18 course reversal change

Gary,

I think we're in danger in getting caught up in legaleze here.

Let's step back a moment, and consider what this means in the real
world.

I'm approaching my destination on an IFR flight plan. I'm in the
clouds, otherwise I'd be doing a visual approach. I'm quite possibly
being bumped around. I'm also quite possibly tired after a long and
stressful flight in IMC.

I'm nicely lined up with the final approach course, at an appropriate
airspeed and altitude. I'm cleared for the approach, but I haven't,
however, heard the magic words "vectors to final".

Does it really make sense that the regulations insist that I fly a
procedure turn to get back to exactly the same point, heading,
altitude and airspeed I'm at now?


(To get back to legaleze
I'm not denying that that's what the 1994 legal opinion says. I'm
just saying that it doesn't gel with my reading of 97.3(p) as it is
written, I'm also saying that I'd like to see the legal opinion
overturned, and whatever regulations there are in 97.20 changed so
that we don't have to fly a procedure turn in these circumstances.

Tim.

On Thu, 3 Nov 2005 13:25:51 -0500, "Gary Drescher"
wrote:

"Tim Auckland" wrote in message
.. .
On Thu, 3 Nov 2005 11:36:25 -0500, "Gary Drescher"
wrote:
I think you're reading 97.3p as though it said "We hereby prescribe that
you
perform a PT when you think it is necessary to reverse direction..."; but
it
was apparently intended to mean "When our TERPS designers think it is
necessary for you to reverse direction, they prescribe a PT (by charting
it
on an approach plate)".

I agree that is in line with the 1994 legal opinion, but I still
wonder if it's what the original drafters of 97.3(p) intended.

If the original drafters of 97.3(p) intended Procedure Turns to be
used in all cases, why did they include the words "reverse direction"
at all?

I suspect they were simply being informative by mentioning the rationale for
the prescription when they stated the definition of a PT. It makes sense
that they'd want pilots to understand what PTs are supposed to be for (even
though, like any other feature of an approach chart, a PT might mistakenly
be prescribed when it's not supposed to be).

--Gary

"Tim Auckland" wrote in message
...
I think we're in danger in getting caught up in legaleze here.

Let's step back a moment, and consider what this means in the real
world.

I'm approaching my destination on an IFR flight plan. I'm in the
clouds, otherwise I'd be doing a visual approach. I'm quite possibly
being bumped around. I'm also quite possibly tired after a long and
stressful flight in IMC.

I'm nicely lined up with the final approach course, at an appropriate
airspeed and altitude. I'm cleared for the approach, but I haven't,
however, heard the magic words "vectors to final".

Does it really make sense that the regulations insist that I fly a
procedure turn to get back to exactly the same point, heading,
altitude and airspeed I'm at now?

Fair enough--let's put aside the legalities for a moment and consider some
real-world scenarios. One scenario that's been discussed occurs when an IAF
is aligned with the FAC (and at the right altitude) but isn't marked NoPT.
The right thing to do in that case is to notify the FAA of a likely chart
error, and they'll promptly issue a NOTAM to fix it. (If pilots and
controllers notify the FAA each time an error like that is noticed on the
ground, few such errors, if any, will still be uncorrected by the time
someone flies the approach.) If I were flying such an approach and the chart
hadn't been corrected yet, I'd ask ATC about it as soon as I noticed the
anomaly. In a lost-comm situation, I suppose I'd just fly straight in, even
though it'd be nominally illegal (but I'd only do that if I were already at
the altitude at which I'd cross if I were to execute the PT).

The other scenario that's beed discussed occurs if you've been cleared
direct to the FAF (rather than via vectors or via a charted course from an
IAF) and you're closely aligned with the FAC (and at the right altitude).
I've never had that happen, but I don't usually fly with a GPS, so I don't
usually get direct clearances in general; I'm unclear, therefore, as to how
common a scenario that might be.

--Gary

On Thu, 3 Nov 2005 17:08:56 -0500, "Gary Drescher"
wrote:

"Tim Auckland" wrote in message
.. .
I think we're in danger in getting caught up in legaleze here.

Let's step back a moment, and consider what this means in the real
world.

I'm approaching my destination on an IFR flight plan. I'm in the
clouds, otherwise I'd be doing a visual approach. I'm quite possibly
being bumped around. I'm also quite possibly tired after a long and
stressful flight in IMC.

I'm nicely lined up with the final approach course, at an appropriate
airspeed and altitude. I'm cleared for the approach, but I haven't,
however, heard the magic words "vectors to final".

Does it really make sense that the regulations insist that I fly a
procedure turn to get back to exactly the same point, heading,
altitude and airspeed I'm at now?

Fair enough--let's put aside the legalities for a moment and consider some
real-world scenarios. One scenario that's been discussed occurs when an IAF
is aligned with the FAC (and at the right altitude) but isn't marked NoPT.
The right thing to do in that case is to notify the FAA of a likely chart
error, and they'll promptly issue a NOTAM to fix it. (If pilots and
controllers notify the FAA each time an error like that is noticed on the
ground, few such errors, if any, will still be uncorrected by the time
someone flies the approach.) If I were flying such an approach and the chart
hadn't been corrected yet, I'd ask ATC about it as soon as I noticed the
anomaly. In a lost-comm situation, I suppose I'd just fly straight in, even
though it'd be nominally illegal (but I'd only do that if I were already at
the altitude at which I'd cross if I were to execute the PT).
No disagreements here.


The other scenario that's beed discussed occurs if you've been cleared
direct to the FAF (rather than via vectors or via a charted course from an
IAF) and you're closely aligned with the FAC (and at the right altitude).
I've never had that happen, but I don't usually fly with a GPS, so I don't
usually get direct clearances in general; I'm unclear, therefore, as to how
common a scenario that might be.
Doesn't have to be GPS. Just about any time you're on a course (VOR
radial, or airway, or NDB bearing, or direct, or vector) which crosses
the extension of a FAC (localiser, VOR, NDB or GPS) you could be
instructed by ATC to intercept the FAC course, assuming that you're
within operational range of the transmitter. Doesn't mean anything
about altitudes, doesn't mean that you're cleared for the approach,
doesn't mean that you've got "vectors to final", just means that you
have to fly that course.

99 times out of 100 youi'll also get "vectors to final", so you're
right, it's not very common in the real world.

Tim.

Tim Auckland wrote:

Here's my current spin on all of this.

I think the AIM writers have an impossible job to do -- they're trying
to clarify two FARS which essentially contradict each other. Hence
the ambiguiity in the AIM.

The FARS in question are

97.3(p) which defines the Procedure Turn as "the maneuver prescribed
when it is necessary to reverse direction..."

and

97.20 which includes by reference the textual description of the
standard instrument procedures, which apparently state that the
Procedure Turn is mandatory (except in the well-known very specific
exceptions).

So, by definition (97.3(p)), Procedure Turns are only relevant when a
course reversal is required, but 97.20 states that a Procedure Turn is
mandatory even if a course reversal is not required.

To me, these two FARS are contradictory.

It's not surprising that the AIM is confusing when it tries to explain
them.

The 1994 legal opinion appears to have been based on 97.20, but I
don't see how it can be reconciled with 97.3(p).

Even within the FAA, there are apparently two schools of thought on
this: the August AIM revision writer clearly supported 97.3(p),
whereas the current proposed revision writers are backing 97.20.

I think the FAA should review 97.20 and the legal opinion in the light
of 97.3(p).

Personally, I hope 97.3(p) wins. To me it's safer, more efficent,
mostly in general use when circumstances highlighting the ambiguity
actually exist, and far more accessible to the piloting community.


If a review were to be conducted the context of both would have to be
carefully considered. In my years of working with this stuff I don't see the
conflict.
97.3(p) is a general statement about procedure elements. What 97.3(p) is
impling when stating "when required" is that a procedure will have a charted
course reversal when it is required by the design circumstances. The toolbox
of TERPS design options include the option to not include a course reversal
where local topography, procedure track alignments, and ATC flow requirements
will permit exclusion of a course reversal in the design.

97.3 is defining symbols and terms, some of which may not appear on all
instrument approach procedures.

97.20 is the regulatory basis for incorporating specific TERPS instrument
approach procedures into Part 97 by reference in the federal register. Where
a course reversal is specified in any given procedure, then it is required
under the context of the definition in 97.3(p) unless one of the conditions
of 91.175(j) exists.

If the original drafters of 97.3(p) intended Procedure Turns to be
used in all cases, why did they include the words "reverse direction"
at all?


Because they knew some procedure could be, and would be, designed without course
reversals. They also knew that some procedures designed with course reversal
would have some NoPT terminal routes.

Tim Auckland wrote:

Doesn't have to be GPS. Just about any time you're on a course (VOR
radial, or airway, or NDB bearing, or direct, or vector) which crosses
the extension of a FAC (localiser, VOR, NDB or GPS) you could be
instructed by ATC to intercept the FAC course, assuming that you're
within operational range of the transmitter. Doesn't mean anything
about altitudes, doesn't mean that you're cleared for the approach,
doesn't mean that you've got "vectors to final", just means that you
have to fly that course.

99 times out of 100 youi'll also get "vectors to final", so you're
right, it's not very common in the real world.


If ATC has set you up to intercept the intermediate course, or an extension
thereof, they have provided "vectors to final." The ambiguity that occasionally
results is usually from vague ATC procedures rather than ambiguous procedure
design.

A new complexity will arrive early next year when the ATC procedure of clearing
pilots direct to the intermediate fix of an RNAV procedure will be finally
officially sanctioned. This will provide additional flexibility but will also
result in confustion.

Then, as the RNAV (RNP) procedures proliferate, this new ATC procedure will not
be permitted with those procedures, which is bound to create even more confusion.

Jose wrote:.


Some charts come with a "noPT sector", which makes sense to me.
Otherwise, the TERPS designers don't really know where I'm coming from,
and whether or not I need to reverse direction.

When an NoPT sector is designated it states "via airways" within that sector
unless it is a TAA in an RNAV procedure (rather rare because most ATC facilities
don't know how to handle TAAs, thus they won't accept the design from AVN).

As to the second part of your statement, can you provide an example of an NoPT
route where the procedure designer wouldn't know where you would be coming from?

Some charts come with a "noPT sector", which makes sense to me.
Otherwise, the TERPS designers don't really know where I'm coming from,
and whether or not I need to reverse direction.

When an NoPT sector is designated it states "via airways" within that sector
unless it is a TAA in an RNAV procedure (rather rare because most ATC facilities
don't know how to handle TAAs, thus they won't accept the design from AVN).

Ok. I didn't know that. It then makes less sense to me.

As to the second part of your statement, can you provide an example of an NoPT
route where the procedure designer wouldn't know where you would be coming from?

All of them. The procedures are designed before I get into the airplane.

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

Jose wrote:

Some charts come with a "noPT sector", which makes sense to me.
Otherwise, the TERPS designers don't really know where I'm coming from,
and whether or not I need to reverse direction.

When an NoPT sector is designated it states "via airways" within that sector
unless it is a TAA in an RNAV procedure (rather rare because most ATC facilities
don't know how to handle TAAs, thus they won't accept the design from AVN).

Ok. I didn't know that. It then makes less sense to me.

What made more sense with your previous understanding?



As to the second part of your statement, can you provide an example of an NoPT
route where the procedure designer wouldn't know where you would be coming from?

All of them. The procedures are designed before I get into the airplane.


Hmmm...well, the procedure requires you to start at the fix that defines the NoPT
terminal route. Where is the mystery in that to the designer?

On Fri, 04 Nov 2005 04:54:26 -0800, wrote:



Tim Auckland wrote:

Doesn't have to be GPS. Just about any time you're on a course (VOR
radial, or airway, or NDB bearing, or direct, or vector) which crosses
the extension of a FAC (localiser, VOR, NDB or GPS) you could be
instructed by ATC to intercept the FAC course, assuming that you're
within operational range of the transmitter. Doesn't mean anything
about altitudes, doesn't mean that you're cleared for the approach,
doesn't mean that you've got "vectors to final", just means that you
have to fly that course.

99 times out of 100 youi'll also get "vectors to final", so you're
right, it's not very common in the real world.


If ATC has set you up to intercept the intermediate course, or an extension
thereof, they have provided "vectors to final." The ambiguity that occasionally
results is usually from vague ATC procedures rather than ambiguous procedure
design.

A new complexity will arrive early next year when the ATC procedure of clearing
pilots direct to the intermediate fix of an RNAV procedure will be finally
officially sanctioned. This will provide additional flexibility but will also
result in confustion.

Then, as the RNAV (RNP) procedures proliferate, this new ATC procedure will not
be permitted with those procedures, which is bound to create even more confusion.
Thanks for the heads-up.