Jim Carter wrote:
I had a question today that I’ve never considered, and need the
experience of the group.



Are there airports with ILS approaches such that if the Glide Slope
component failed or went OTS, the entire approach would be un-executable
by regulation? I’ve always assumed that with the GS OTS I’d just revert
to the LOC, but are there approaches were the full ILS is approved but
the LOC only isn’t? In other words, are there precision approaches where
vertical guidance is required and there is no non-precision alternative?



There are some procedures that only have precision ILS minima published
on the procedure, so if the GS went OTS, then that procedure would not
be available simply because that procedure requires the glideslope and
has no LOC line of minima. If they have circling minima on the ILS then
there is a note "Circling requires descent on glideslope to MDA".
See the example at Butte, Montana;
http://www.naco.faa.gov/d-tpp/0608/00588I15.PDF
In that example, there is no non-precision alternative on that
particular plate, but there is a LOC procedure published on a separate
approach plate if you want to fly the LOC only procedure.
I don't know offhand if there are any ILS runways that have no "LOC
only" mins available at all.

JPH