ILS, a detailed look

[Pilot52]

Hi all, I'm just wondering what the difference is between different types of ILS approaches (CAT II, CAT III). At what airports would you usually find each and are they correctly modeled in FS2k2?

Real pilots are encouraged to answer.

[Frederf]

bump

[Blackcat]

To be a little more helpful than the idiot above (and all the other idiots who contribute to questions with nothing more helpful than 'bump') the ILS sytems are categorised according, in simple terms, to their quality ie calibrated accuracy, terrain and obstruction criteria etc. The CAT dictates the decision altitude (or height if you are working on QFE) and permissable runway visual range (RVR) for the given met conditions.

The actual limits are given on the approach plates for each airport and more generic definitions are found in Aerad or Jeppeson flight guide manuals. Basically, the higher the ILS CAT, the lower the limits for the approach eg a CAT1 ILS will give a decision altitude of 200'; a CAT 3A will allow autoland in, effectiely, zero visibility. The larger airports eg LHR, LGW in the UK have CAT 3 capability. The other point worth noting is that the aircraft ILS avionics have to be licensed to an appropriate CAT; the aircraft I fly is cleared to CAT2 limits which is a DA of 100' with RVR of 300m. Hope this helps.

[Sparky61]

Blackcat,
Your close. The real deciding factor is the a/c equipment, approach lighting system, type of runway lighting and high speed turnoffs. ILS's are all calibrated to a high degree of accuracy.

[wileyecoyote]

Most 'idiots' (including myself, thank you very much) bump the topic, simply because they want to know the answer as well. I sometimes bump it so that I have a response in the thread allowing me to recieve an e-mail telling me when a followup has been posted.

That is usually the reason these 'idiots' bump it. You might try thinking about the reason for doing this before getting offensive.

Regards,

http://www.flightsim.com/dcforum/Use...cd2eb270d6.jpg

[artburke]

Can't say as I considered you an idiot for "bump"-ing the post, but I certainly appreciate your explanation. Had no idea what it was supposed to mean!

As for the original question, I have an add-on. If a CAT IIIa will permit landing in zero-zero visibility, may (can?) I assume there is also ground radar available? It goes without saying (maybe!) that if you land in heavy fog, rain, snow, whatever, you're going to have a hell of a time finding the taxiway at all - high speed or otherwise!

Art

[Blackcat]

Frederf,wiley

Accept my apologies but perhaps the use of plain english eg 'Yea, I'd like to know about that too' might be more comprehensible make life a little easier - bear in mind that this forum attracts an international audience which is not au fait with colloquial PC forum jargon (and why 'bump' anyway?).

Sparkey61

Thanks - I was just trying to keep it simple - I do use Cat 1,2 and 3 approaches every working day.

[TRex]

There are ground radars but mostly not in use as proved by SAS's MD-82 and private Cessna collision in milano in last september.