Roy Smith wrote:

wrote:
Charting convention places the burden for clarity of the course
reversal in the profile view.

Frank,

I'm not saying you're wrong (in fact, what you say makes a lot of
sense), but is there some reference you could give to that? It's not
anything I've ever seen in any of the standard reference materials.

The NACO chart legend implies it, but I suspect it is only spelled out in
the IACC specs. (Inter-agency Cartographic Commission, or something like
that, specifications.) Often, the feds miss spelling out this stuff to the
users, because it makes sense to all of them sitting around a table for
their closed meetings.~



On that note, I remember once flying the MGJ ILS-3 for practice
(http://www.myairplane.com/databases/...fs/05264I3.pdf). Shame
on me, I hadn't really briefed the approach, and just winged it. I flew
the procedure turn a minute outside of the LOM and ended up AFU.

It's kind of tricky. The first trick is that the PT doesn't start at
the LOM, but at DIYAD. The second trick is that there's a stepdown at
NISSN inbound from the PT, so you really need to be outside of NISSN
before you start the PT, not just outside of DIYAD. The third trick is
that DIYAD and NISSN are both defined by DME, but from different sources
(neither of which is the ILS).

There's a note on the profile view saying "Remain within 10 NM", but I'm
not 100% sure from *where*. I'm reasonably sure it means 10 NM from
DIYAD, but given NISSN, I'm not quite certain about that.

The descending thick black line begins at DIYAD, so that is the fix upon
which the PT is predicated. If you feel this is inadequately explained, a
well crafted letter to the NACO charting folks in Silver Springs, MD would
be helpful. In my many years of flying it seemed obvious to me, but gee, I
can't cite a public reference.



Lastly, it beats the hell out of me why anybody would care that DIYAD is
13.5 DME from HUO. Given the crossing angles, I could see that being on
the localizer and 20.8 DME from SAX is a good way to identify NISSN, but
being on the localizer and being 13.5 DME from HUO is pretty worthless
as a way to identify DIYAD. GPS is wonderful :-)

The 13.5 DME is there for arrival from HUO to the LOC. The fact it's
charted in the profile view is a mistake in the manner in which the data
were entered into the system. Keep in mind, you're dealing with the same
FAA here who has all but thrown the towel in on WAAS on one hand, yet on the
other hand is going to make it work, "damn it!" ...and so forth.



This is a great approach for training purposes. It's a confusing mess
for flying for real. But it does serve to show a student why briefing
an approach before you actually get to the IAF is a good idea :-)