procedure turns revisited

In article .com,
wrote:

Now let me ask a question. What if ATC clears you direct to the VOR
and then clears you for the "straight-in" approach? Isn't the
controller's instruction in conflict with the AIM? Who wins,
hypothetically speaking (say you can't contact him for clarification)?

I had almost exactly this same situation happen the other day with NY
Approach. We were coming into White Plains (HPN) from the north, IFR.
Controller gave us something like, "direct FARAN, cleared ILS-16". FARAN's
not an IAF, the route from FARAN inbound is not marked NoPT, we hasn't
giving us vectors. By strict interpretation of the rules, he gave us a bum
clearance. On the other hand, not only did I know that he wanted us to fly
the approach straight-in, but there was no practical reason why anything
else would make any sense, so we did it.

The bottom line is that the AIM just hasn't caught up with real life.

"Roy Smith" wrote in message
...
I had almost exactly this same situation happen the other day with NY
Approach. We were coming into White Plains (HPN) from the north, IFR.
Controller gave us something like, "direct FARAN, cleared ILS-16".
FARAN's
not an IAF, the route from FARAN inbound is not marked NoPT, we hasn't
giving us vectors. By strict interpretation of the rules, he gave us a
bum
clearance. On the other hand, not only did I know that he wanted us to
fly
the approach straight-in, but there was no practical reason why anything
else would make any sense, so we did it.

The bottom line is that the AIM just hasn't caught up with real life.

If you regard the direct clearance as an implicit vector, then it was all
kosher. And I think the vector interpretation is reasonable: ATC was telling
you to fly the (off-airway) heading that takes you to FARAN (even though it
was left to you, or your equipment, to compute the numerical value of that
heading).

--Gary

ATC was telling
you to fly the (off-airway) heading that takes you to FARAN (even though it
was left to you, or your equipment, to compute the numerical value of that
heading).

Then it's not a vector. A vector is "go in this direction". What you
got was "go to this point".

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

Jose wrote:
ATC was telling you to fly the (off-airway) heading that takes you
to FARAN (even though it was left to you, or your equipment, to
compute the numerical value of that heading).

Then it's not a vector.

Correct. A vector is defined in the PCG as, "a heading issued to an
aircraft to provide navigational guidance by radar". Unfortunately,
there is no PCG defintion of "heading", so we need to fall back on the
conventional definition of "put this number at the top of your DG and
keep it there".

The problem is, it's obvious to everybody (i.e. to both ATC and to
pilots) that "direct FARAN, cleared approach" is a completely
reasonable, flyable, safe, and convenient clearance to issue to a /G
aircraft under radar surveillance. The fact that it's also against
the rules just points out how silly the rules are.

Roy Smith wrote:
In article .com,
wrote:


Now let me ask a question. What if ATC clears you direct to the VOR
and then clears you for the "straight-in" approach? Isn't the
controller's instruction in conflict with the AIM? Who wins,
hypothetically speaking (say you can't contact him for clarification)?


I had almost exactly this same situation happen the other day with NY
Approach. We were coming into White Plains (HPN) from the north, IFR.
Controller gave us something like, "direct FARAN, cleared ILS-16". FARAN's
not an IAF, the route from FARAN inbound is not marked NoPT, we hasn't
giving us vectors. By strict interpretation of the rules, he gave us a bum
clearance. On the other hand, not only did I know that he wanted us to fly
the approach straight-in, but there was no practical reason why anything
else would make any sense, so we did it.

The bottom line is that the AIM just hasn't caught up with real life.

Not exactly. The following was added to the AIM recently. Note that it
is limited to RNAV IAPs. There were lenghty discussions within FAA and
with industry. It was at first proposed to permit the practice for all
instrument approach procedures with an intermediate fix, and limit it to
GPS or advanced RNAV aircraft. FAA's ATC management nixed the idea
for conventional, ground-based IAPs.

So, it isn't really the AIM not staying up with the "real world," it's
the real world inventing its own rules.


5-4-7 i. ATC may clear aircraft that have filed an Advanced RNAV
equipment suffix to the intermediate fix when clearing aircraft for an
instrument approach procedure. ATC will take the following actions when
clearing Advanced RNAV aircraft to the intermediate fix:
1. Provide radar monitoring to the intermediate fix.
2. Advise the pilot to expect clearance direct to the intermediate fix
at least 5 miles from the fix.
NOTE-
This is to allow the pilot to program the RNAV equipment to allow the
aircraft to fly to the intermediate fix when cleared by ATC.
3. Assign an altitude to maintain until the intermediate fix.
4. Insure the aircraft is on a course that will intercept the
intermediate segment at an angle not greater than 90 degrees and is at
an altitude that will permit normal descent from the intermediate fix to
the final approach fix.

Sam Spade wrote:

5-4-7 i. ATC may clear aircraft that have filed an Advanced RNAV
equipment suffix to the intermediate fix when clearing aircraft for an
instrument approach procedure.

Wouldn't a cleaner and more permanent change be to mark those
intermediate fixes as IAF or IF/IAF on the GPS/RNAV approach plates?
Or is there a reason that isn't practical? I guess that means the
initial segment would have a length of zero. (perhaps that's not
allowed in the TERPS?)

wrote:
Sam Spade wrote:


5-4-7 i. ATC may clear aircraft that have filed an Advanced RNAV
equipment suffix to the intermediate fix when clearing aircraft for an
instrument approach procedure.


Wouldn't a cleaner and more permanent change be to mark those
intermediate fixes as IAF or IF/IAF on the GPS/RNAV approach plates?
Or is there a reason that isn't practical? I guess that means the
initial segment would have a length of zero. (perhaps that's not
allowed in the TERPS?)

There was a charting change a few years back to do just that. It takes
a long time for the results to factor through the system.

ATC may clear aircraft that have filed an Advanced RNAV
equipment suffix to the intermediate fix when clearing aircraft for an
instrument approach procedure.

How does this jibe with the letter of interp requiring an a/c to use
an IAF or be vectored to final. Will this language be added to the
..65 so it can be said to be approved by the Administrator?

Greg Esres wrote:
ATC may clear aircraft that have filed an Advanced RNAV
equipment suffix to the intermediate fix when clearing aircraft for an
instrument approach procedure.

How does this jibe with the letter of interp requiring an a/c to use
an IAF or be vectored to final. Will this language be added to the
.65 so it can be said to be approved by the Administrator?

It was added to 7110.65R this past February.

Here is the new portion of 7110.65R, 4-8-1:

"Area Navigation (RNAV)
Standard Instrument Approach Procedures may
begin at an Intermediate Approach Fix for aircraft
that have filed an Advanced RNAV equipment suffix
when the conditions of subpara b4 are met."

And, here is the background material for the change in the back of 7110.65R:

BACKGROUND: Currently, paragraph 4−8−1 provides two methods for clearing
aircraft for a Standard Instrument
Approach: 1) clear the aircraft to the Initial Approach Fix (IAF) (or
Intermediate Fix (IF) when no IAF is depicted), or 2)
vector the aircraft to the final approach course. These procedures
create undue delay to pilots and air traffic control under
certain conditions. When an aircraft utilizing Area Navigation (RNAV) is
aligned with the final approach course and at an
altitude not requiring abnormal descent to the final approach fix, air
traffic must either clear the aircraft to an IAF or vector the
aircraft to the final approach course.
RNAV aircraft are capable of flying direct to a fix or waypoint with
more precision than a radar vector. A direct−to clearance
eliminates variables of aircraft drift when changing altitudes and/or
airspace when a strong wind shear is present. A radar
vector to a typical RNAV approach would place the aircraft within 2
miles of the IF. This requires the controller to monitor the
aircraft in variable wind conditions to ensure it does not intercept the
final approach course prior to the IF. The final approach
course does not extend beyond the IF as a radial on a conventional approach.
There are several supporting examples permitting RNAV aircraft to be
cleared direct to an IF to execute an instrument
approach procedure. FAA Order 8260.3B, United States Standard for
Terminal Instrument Procedures (TERPS),
paragraph 230, provides for an initial approach to be made along an arc,
radial, course, heading, radar vector, or combination
thereof when the IF is part of the en route structure. In this case, the
approach commences at the IF and a direct−to clearance
provides a course for the aircraft to fly. Aircraft may be cleared to
the IAF/IF for RNAV approaches. When a Terminal Arrival
Area (TAA) is depicted, most TAAs specify NoPT (No Procedure Turn) for
the straight−in segment. This permits aircraft to
fly the same segment of the instrument procedure as any RNAV approach
from the IF. 14 CFR Section 91.175(i) contains the
following statement: “When operating on an unpublished route or while
being radar vectored, the pilot, when an approach
clearance is received, shall, in addition to complying with Sec. 91.177,
maintain the last altitude assigned to that pilot until the
aircraft is established on a segment of a published route or instrument
approach procedure unless a different altitude is
assigned by ATC.� Aircraft are on an unpublished route when cleared
direct−to a fix or waypoint and the intermediate
segment defines the segment the aircraft must be established on for the
approach.
Issuing aircraft a direct−to clearance to the IF will enhance the
movement of aircraft in the terminal environment. Requiring
the controller to advise the pilot in advance of the clearance, limiting
the turn angle to intercept the intermediate segment,
accounting for descent along the approach and providing radar
monitoring, the procedure will ensure the pilot is able to
safely maneuver the aircraft for the approach.
3

It was added to 7110.65R this past February.

Ah, thank you. Mine is outdated.