The longer runways are more likely to have critical areas. Runways whose
taxiways get too close to the runway is also a factor. We have that problem
here at BIL. The last 3000 feet of taxiway angles in toward the runway
creating the need for an ILS hold area because you get in the way of the
localizer.



"Matt Whiting" wrote in message
...
Newps wrote:

"Matt Whiting" wrote in message
...



I suspect it has to do with the location of the antenna. I don't they
they are all located in exactly the same spot WRT to the runway.


The glideslopes are as they are all positioned to bring you to the same
spot
on every runway. The localizer is sited so it is a certain width at the
approach end of the runway, therefore they will move the localizer
antenna
closer to or farther away from the departure end of the runway to
achieve
that.



Then why do some runways have ILS critical areas and others do not?

Matt