On Tue, 14 Mar 2006 00:05:04 GMT, "Steven P. McNicoll"
wrote:


"rps" wrote in message
roups.com...

My answer, based on what I learned from this thread and by reading
elsewhere, is that you cannot substitute GPS for ADF on this approach
because:

1) The chart doesn't indicate an overlay approach, such as with the
nomenclature "NDB/GPS" in the title; and
2) the NDB is the "primary" signal source for the approach. (See the
relevant AIM sections.)


Right, GPS cannot substitute for ADF on this approach because ADF is the
principal instrument approach navigation source. For that same reason GPS
cannot substitute for DME on the VOR/DME or TACAN Z RWY 15 at MTN.

But if you can't substitute DME to fly an arc because it's the primary
source of navigation then why is "DME arc" specifically listed in AIM
1-1-19 (f)(1)(a)(2) and blah/DME with arcs used as the examples of
permissible substitution on the AOPA GPS substitution page? That's
the piece of the puzzle I'm missing here.