On Fri, 10 Mar 2006 12:11:24 GMT, "Steven P. McNicoll"
wrote:


"Peter Clark" wrote in message
.. .

Might I ask what makes that approach any different than the ILS/DME
RWY 2 approach APOA uses as the sample in their "Use of GPS in lieu"
piece (
http://www.aopa.org/whatsnew/air_tra...u.html#figurea )
where they say "DME arcs associated with instrument approaches may be
flown using GPS distance provided the DME transmitter, on which the
arc is based, is identified in the GPS database (see Figure A)." ?


The ILS/DME RWY 2 at DRO uses a localizer for the principal instrument
approach navigation source. The VOR/DME or TACAN Z RWY 15 at MTN uses DME
as the principal instrument approach navigation source.

Um, OK, I'm thick. I don't get what substitution rule I'm still
missing? With either approach you're using the VOR head for lateral
guidance and reading the distance from some fix in the GPS database
from the GPS head. Even the example approach used for how to do a DME
ARC in the KLN 94 GPS manual is an VOR/DME approach using an arc.