Hi folks. I've got a bit of a puzzle here.
First off, I'm a student pilot, so maybe I haven't gotten to this yet.

Take a look at the ILS 18 plate for Springdale, AR (ASG):
http://myairplane.com/databases/appr...l/ASG_ir18.pdf

First, note that the approach is "ILS RWY 18"
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Next, read in the notes section:
Circling NA east of Rwy 18-36, inoperative table does not apply.
DME from RZC VORTAC
Simultaneous reception of I-ASG and RZC DME required.
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So, the way I read this, DME is not required, since the approach is ILS
not ILS DME, but it is required since "simultaneous reception ... is
required."

I guess my real question is, "Is this approach authorized for an aircraft
without DME? And if not, why don't they call it ILS-DME?" but read on for
my thinking...

Looking at the chart, here are the uses of DME that I see:
1. DME arcs to intercept the localizer
2. A 3.8 DME non-precision MAP (my Jepp plate shows a non-precision decent
with DME 3.8 as the MAP)
3. WESTY intersection, 18 DME out, which can also be identified by a
cross-radial from the DAK VOR.

Now, this is how I reason (i.e. rationalize. my way out of these:
1. I tune the RZC VORTAC and fly the DME ARC, but once I turn to intercept
the localizer, I no longer care about the ARC, so I don't need DME anymore.
2. DME would be helpful here, and simultaneous reception would be
required, but I could also time from the FAF to identify the MAP.
3. I can swap VOR receivers once safely established on missed approach, so
I shouldn't need this for the inbound part of the approach.

To my thinking, #2 is the shakiest logic. Still, if DME is required, why
don't they just call it an ILS-DME approach?
--
Don Faulkner, KB5WPM |
(This space | "All that is gold does not glitter."
unintentionally | "Not all those who wander are lost."
left blank) | -- J.R.R. Tolkien