"Mark Hansen" wrote in message
...

Sure. But the tower is the controlling authority which is instructing
planes to hold clear of the ILS critical area.

If the tower is not in operation, who gives the order?


Nobody.



If the pilot on the ground is supposed to know when to hold clear,
how does he know? He may not even know a plane is using the
ILS. And besides, the tower only needs to keep it clear when the
weather is below 800/2, so does this go for the non-towered airport
as well?


Well, if it's only a problem when an aircraft is on the ILS and it's below
800/2, and given that ATC isn't going to release an IFR departure if an
aircraft is on the ILS, then it doesn't appear to be a problem.



Where is this defined?


I don't believe it's defined anywhere.