ILS question

Mick Ruthven wrote:

I don't think that 10nm circle is a 4000-foot-protected area. The 4000 feet
refers to the hold in lieu of a PT, and there's no distance specified for it
except for the "one minute" which really can't be interpreted as a distance
within which you can descend to 4000 feet. I'd say the only way to properly
descend on the LOC 17 NM out is to intercept the GS and follow it down.

That will usually work, but it technically is not legal. The G/S is merely an
additional nav aid until the PFAF. At LAX there have been enforcement
violations for air carriers following the G/S prior to the PFAF. On a really
hot day, the airspace below rises sufficiently that TRACON airspace for the
Ontario area gets compromised unless the DME fixes and baro altitudes are used.