ILS Ground Kit Setup

[llondel]

Having seen various items on here and elsewhere about out-of-service ILS kit, how does the ILS get set up in the first place? My guess would be that a rough alignment is done from the ground and a specially-equipped aircraft is flown along the line, tweak and repeat until it's correct. Once set up, how often is it checked?

[OzExpat]

The "kit", as you call it, is normally setup to achieve something close to a THR crossing height of about 50 feet. The actual location of the GP will be a function of the ground elevation in the vicinity of the GP site and the THR elevation. The LLZ (or LOC, if you prefer) is setup to provide a standard path width at the THR, so the LLZ/LOC position will be a function of the length of the runway itself.

ICAO requires calibration checks every 6 months. This entails a full check every 12 months and a slightly abbreviated check in between times.

If the setup has been done right in the first place and the alarm monitors haven't been monkeyed with in between times, very little "tweaking" is usually necessary. Sadly, this isn't always the case so, yes, it can be a case of having the calibration aircraft fly many approaches and direct the technicians to make appropriate adjustments to course width and/or approach path.

There's a bit more to it than that, but that's the general guts of it.

[Pugilistic Animus]

I'm not sure how to reference this properly, but FAA TERPS criteria as well as OCS criteria for ILS/ LPV's NDB's etc. etc. can be found in the FAA Flight Procedures Standards Orders

in this case order 8260.3B chapt. 9 [not sure if I referenced that in the correct format???]

http://www.faa.gov/about/office_org/headquarters_offices/avs/offices/afs/afs400/afs420/policies_guidance/orders/media/Order%208260.3_1-18.pdf