What is service volume of ILS?

[ToiletDuck]

Someone asked me this question as I'm getting ready for my CFI and I don't know the answer. I don't fully understand the question either. I've been lookin around and can't find anything on this. Anyone know the answer?

 

[Workin'Stiff]

I'd tell them to find a hobby....

 

[ToiletDuck]

lol why what's he meaning with this question? They were all drilling me with questions and I was pretty much nailing em all then he asked this and I had no idea.

 

[Yank McCobb]

From the AIM 1-1-9

"The localizer provides course guidance throughout the descent path to the runway threshold from a distance of 18 NM from the antenna between an altitude of 1000 ft above the highest terrain along the course line and 4500 ft above the elevation of the antenna height.

To 10 degrees either side of the course along a radius of 18 NM from the antenna; and

From 10 to 35 degrees either side of the course along a radius of 10 NM."

"The glide path projection angle is normally adjusted to 3 degrees above horizontal so that it intersects the MM at about 200 feet and the OM at about 1400 feet above the runway elevation. The glide slope is normally usable to the distance of 10 NM. However, at some locations, the glide slope has been certified for an extended service volume which exceeds 10 NM."

 

[Mickey]

It's a great question. I get FO's trying to ID the ILS way too far out and they can't figure why they don't get a good signal.


LOC coverage +/- 35 degrees=10nm +/-10 degrees=18nm
take care

 

[Workin'Stiff]

I don't mean to downplay it, though....

 

[ToiletDuck]

If he would have just asked the range that would have been better lol.

 

[Workin'Stiff]

haha... Well, that is the correct terminology for the question he was asking...