Originally Posted by
flyandive
Besides the ILS is guaranteed out to 18nm. 35 degrees either side out to 10nm, 10 degrees out to 18nm.
That is not for the ILS, that is for the localizer beam. The GS has a different footprint, I think somebody said ten miles.
Be aware that some ILS's have coverage far exceeding the standard mins...if ATC clears you to intercept the LOC 25NM out, then that LOC is good to at least 25NM.