"rps" wrote in message
oups.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.