ILS or LOC approach?

YKM (Yakama, Washington) RWY 27
BFI (Boeing Field, Seattle) RWY 13R
ACV (Arcata, California) RWY 32



J Haggerty wrote:

Here's an ILS with ILS and Circling minima, but LOC is NA.
This one has the note on the procedure that states "Circling requires
descent on GS to MDA".
http://www.naco.faa.gov/d-tpp/0504/00388ID32.PDF
For May 12th effective date, the link is;
http://www.naco.faa.gov/d-tpp/0505/00388ID32.PDF
Sheridan, WY (KSHR) ILS/DME Rwy 32

JPH

wrote:

Can you give us some examples?
Stan

On Tue, 03 May 2005 20:04:24 -0500, J Haggerty
wrote:


There are actually a few ILS procedures that do not have LOC minima.
That would normally be caused by very high obstacles that would keep
the LOC MDA too high, but are not high enough to penetrate the
precision obstacle clearance slope.

The original poster thought that all ILS procedures had LOC minima
available. There are no LOC minima available on that procedure. The
LOC-2 you mentioned is a separate procedure, and not part of the ILS
procedure.
This other example I mentioned is what you were thinking about, an ILS
procedure with no other LOC procedure at the airport.
http://www.naco.faa.gov/d-tpp/0505/00388ID32.PDF
Sheridan, Wyoming.

wrote:
Is this an example of what we were talking about?

There is a separate LOC-2 approach for this airport.


That's a separate, stand-alone procedure, not part of the ILS procedure.
Clearance for the ILS approach in that situation could not be construed
as having a clearance for the LOC-2 procedure if the GS failed.

I thought we were discussing situations with an ILS and NO LOC
approach.

Depends on your outlook. For that procedure (ILS) the LOC minimums are
NA. For the other example, there is not even a separate LOC procedure
available.



On Sat, 07 May 2005 22:31:48 -0500, J Haggerty
wrote:


Found one.
ILS Rwy 16R, Reno, NV (KRNO)
LOC and circling minimums NA.
This isn't the one I was thinking of. The one I was thinking of had ILS
and circling minima, but LOC minima was NA. I'll post that one if I run
across it.
Plate can be viewed at this site;
http://www.naco.faa.gov/d-tpp/0504/00346I16R.PDF



wrote:


Can you give us some examples?
Stan

On Tue, 03 May 2005 20:04:24 -0500, J Haggerty
wrote:



There are actually a few ILS procedures that do not have LOC minima.
That would normally be caused by very high obstacles that would keep
the LOC MDA too high, but are not high enough to penetrate the
precision obstacle clearance slope.




JPH

wrote:
However, I have a hard time imagining the TERPS criteria that dictate
that an ILS is acceptable, but a LOC approach would not be. What are
the circumstances, I wonder, that would allow a descent to ILS
minimums but not allow a descent to LOC minimums?

I could imagine a location where there is no way to create a non-precision
FAF; no dry land to place an OM, and no useable VOR cross-fix.

wrote:

On Sun, 08 May 2005 15:26:25 -0500, J Haggerty
wrote:



However, I have a hard time imagining the TERPS criteria that dictate
that an ILS is acceptable, but a LOC approach would not be. What are
the circumstances, I wonder, that would allow a descent to ILS
minimums but not allow a descent to LOC minimums?

It typically is where there are a series of obstacles that the ILS
glide-slope surface can clear, but there is no way of providing sufficient
stepdown fixes to clear all those obstacles for a LOC non-precision
profile.

So on the SHR ILS/DME 32, the missed approach point for the circling
approach is 1.5 DME from I-SHR. Do you always assume that the last fix
on the profile view is the MAP for the non-precision approach on the
ILS plate? Usually non-precision MAPs coincide with the beginning of
the runway, but not always.

Anyhow, just wondering if that can become ambiguous in some corner
cases.

Peter wrote:

So on the SHR ILS/DME 32, the missed approach point for the circling
approach is 1.5 DME from I-SHR. Do you always assume that the last fix
on the profile view is the MAP for the non-precision approach on the
ILS plate? Usually non-precision MAPs coincide with the beginning of
the runway, but not always.

Yep. And, the timing table gives another check except when DME is
required, then it's blank.

The MAP is usually the threshold for an IAP with straight-in minimums, but
it could be prior to the threshold with dashed lines afterwards, or it
could be after the threshold for an on-airport VOR or NDB.



Anyhow, just wondering if that can become ambiguous in some corner
cases.

Yeah, but in the ILS at SHR mentioned previously, the dashed line shows
the missed approach beginning at the decision height (not the MDA for
the circling approach) and there is DME, so the timing table is blank,
and in the little airport diagram there is no "FAF to MAP XX NM" blurb.

In other words, on that particular plate, there is nothing identifying
the missed approach point for the circling approach. There just
happens to be this fix at the threshold.

If there also happened to be an inner marker, that would show up on the
plate, but it has nothing to do with the circling approach. So how can
you be sure which fix is the MAP for the ILS-circle-to-land or LOC
approach that is co-charted with an ILS?

The Jeppesen chart shows an "M" at the 1.5 I-SHR DME, which means
non-precision MAP.

Peter wrote:

Yeah, but in the ILS at SHR mentioned previously, the dashed line shows
the missed approach beginning at the decision height (not the MDA for
the circling approach) and there is DME, so the timing table is blank,
and in the little airport diagram there is no "FAF to MAP XX NM" blurb.

In other words, on that particular plate, there is nothing identifying
the missed approach point for the circling approach. There just
happens to be this fix at the threshold.

If there also happened to be an inner marker, that would show up on the
plate, but it has nothing to do with the circling approach. So how can
you be sure which fix is the MAP for the ILS-circle-to-land or LOC
approach that is co-charted with an ILS?