Bloggs,
I'm with maggot - not convinced. Unless we're talking about the need for CATIII approaches in heavy fog (not likely at Cooly), RNP-AR is the future and seems to make more financial sense.
That beloved DC-9 of yours (and the crews that fly them) will get with the times eventually! Heck, you might even be able to do the RNAV-Z onto 21 in PH next time the ILS is out!
