VOR-DME wrote:

Yeah - I didn't see the (18.3) at first glance. I have to agree
that's well within tolerance for identifying the int. I was thinking
it was perhaps twice that far. I also agree that the naming
convention would indicate that the DME is only required for the LOC
approach, so your interpretation makes sense even if intuitively one
doesn't expect to need DME to identify a FAF when there's a marker.


Given that a marker isn't used alone, that it's only purpose is to fix
position along a track formed by another navaid, one would think that the OM
would be sufficient to define the FAF. Not so. Reception of the marker on
the glideslope at 3000' MSL assures the pilot that he's not on a false
glideslope while flying the ILS, but it's not good enough alone to serve as
a FAF on the localizer approach.