@ Genghis
Very sensible, but does anybody know how often (c) or (d) of that list actually happen?
In 42 years of ATC, I've only come across this once. I guess the angel on my headset has been looking after me !
In the early 80's someone landed safely at Liverpool on the closed runway 08 instead of 09. I believe he said he had been misled by a false back beam from the 27 ILS. There was no ILS for 09 - it was SRA's to 1/2 or 2 miles, or a visual. Anyway, CAAFU promptly sent a 748 from Teesside & carried out item d) = "Accident/Incident flight inspections" in spekesoftly's list. Needless to say, there was no fault with the ILS.