ILS for a RWY not always ON?

[Razor18]

Tried ILS landing the other day (Kobuleti), and couldn't get any LOC/GS response (ILS power ON, frequency OK, ILS button pressed (down on the nav source panel, placed beside STPT and TACAN etc.). Didn't hear ILS morse code either, just the TACAN, after volume buttons all pulled out (A-10C II starts with all volume buttons pushed in, but that's another story). Tried ILS on other airfields, same thing. Asked on forum, somebody told ILS is only active, if that ILS equipped runway is "forced" to be used due to stronger than 7 m/s wind from that direction, and ISL also will only be activated then. Is this right? Thanks if not, but if it is so, how could we use ILS if no wind but bad weather? Shouldn't they be always on?

 

 

Thanks, sorry if misunderstood something.

[Frederf]

You understand correctly. Landing aids associated with runway (2NDB, ILS, PRMG) are turned off based on wind direction, wind speed, and headwind/tailwind components in a complicated way. The selection is similar but not identical to the criteria that ATC picks which runway for you to land on. In civil aviation radio landing aids are not shut down unless they conflict with other aids.

[Razor18]

Just for the sake of optional usage, I just don't understand why can't they (all ILS) be left always on, especially if ATC can choose another RWY used independently anyway.

 

 

Thanks for the clarification tough...

[drPhibes]

To quote ICAO Annex 10 volume 1, the international standard for radio navigation aids:

3.1.2.7 At those locations where two separate ILS facilities serve opposite ends of a single runway, an interlock shall

ensure that only the localizer serving the approach direction in use shall radiate, except where the localizer in operational use

is Facility Performance Category I — ILS and no operationally harmful interference results.

3.1.2.7.1 Recommendation.— At those locations where two separate ILS facilities serve opposite ends of a single

runway and where a Facility Performance Category I — ILS is to be used for auto-coupled approaches and landings in

visual conditions an interlock should ensure that only the localizer serving the approach direction in use radiates, providing

the other localizer is not required for simultaneous operational use.

Generelly speaking, you'll never have ILS systems in both runway ends radiating at the same time.

 

The problem with DCS is that the ILS interlock logic doesn't follow the active runway logic. A headwind of >7kts is required for the ILS to be activated, which is wrong.

[Razor18]

I understand, but Kobuleti for instance is one of those airfields, where there is only one runway direction equipped with ILS anyways. So there I don't see the point for NOT operating that single one, as there is not even the interlock problem present.

 

 

On airfields with two ILS directions on the same runway, operation could depend on ATC's decision in the background, no matter if you call them for landing or not. Just my 2 cents...

[randomTOTEN]

So there I don't see the point for NOT operating that single one, as there is not even the interlock problem present.

That decision could simply be above your pay grade. The designation of a runway under calm winds is dictated by other factors than just ILS. Concerns like terrain, noise, nearby airspace, traffic flows for different airports.

Not saying this is correct in DCS, but I'm saying these are concerns when deciding the "default" traffic flow when weather isn't an issue.

And they might not be the same concerns which control the placement of the ILS. They may want the majority of landings to be in a certain direction, but can only place an ILS for arrivals from the sea (perhaps due to terrain).

 

I don't believe DCS AI ATC can factor in visibility to make it's runway decision, so you probably will get in situations in which the ILS is required, but because of the AI limitations it won't be enabled.

 

I guess in that scenario you just have to divert, or accept the AI limitation and build the mission to avoid that problem.

 

These concerns aren't entirely unrealistic. I've made a diversion from an airport with a functional ILS, because it couldn't be used due to traffic restrictions.

[Razor18]

I'm just talking about DCS, not RL. Why not have them on by default. If you want to use it, you can, if you don't want to, then you don't.

[Glide]

I believe there is quite a variety of ILS configurations around the maps. The Caucasus map has some really nice ones. You can see Kutaisi from miles away all the time. Gudauta is just a couple of trucks shining light on the thresholds. A reliable way to signal ILS to turn on would be ideal.