So it's based on the various degrees of runway visibility (i.e. how well you can see the runway)?

The "only" difference between CAT I, II and III is Minimums. In general, at least here in Canada, CAT I gives 200ft AGL, CATII between 200ft and 100ft and CAT III is basically autoland.When you get you IFR License (IRL of course) you can only shoot CAT Iregards,Igor

Both your loc bar "AND" your GS bar must be active "AND" your a/c MUST be below the glide slope before you select APP.vololiberista

Actually most autopilots will intercept the glideslope from above, but it will chase around a bit, and of course in real life this is a bad idea... false glideslopes. FS9 doesn't simulate false glideslopes though so it doesn't really matter but if you want to do it as in real life, yes you must be below the glideslope on intercept. This is not however a MUST for the autopilot system in FS.

Actually most autopilots will intercept the glideslope from above, but it will chase around a bit, and of course in real life this is a bad idea... false glideslopes. FS9 doesn't simulate false glideslopes though so it doesn't really matter but if you want to do it as in real life, yes you must be below the glideslope on intercept. This is not however a MUST for the autopilot system in FS.

All the AP's I have used in FS will not lock onto the glide slope from above! And although what you say about reality is correct it's definately bad practice and if you did that for your 6 monthly check the airline would be most unimpressed!!!!! So in the sim you shouldn't copy that! Yes, in the sim we can do lots of things wrong and get away with it. But it's always the better idea to aim to fly correctly.vololiberista

Alright. In a nutshell, what is the difference between the 3 categories of ILS (CAT I, CAT II, CAT III)?

Alright. In a nutshell, what is the difference between the 3 categories of ILS (CAT I, CAT II, CAT III)?

You will see below the relationship between DH(Decision height-in feet) and RVR(Runway visual range-in metres)All the decision heights for CATIIIb are "less than" which in effect allows for zero visibility.BTW LIMZ is CATIvololiberista

The categories are:Category I Decision Height (DH) 200 feet and Runway Visual Range (RVR) 2,400 feet (with touchdown zone and centerline lighting, RVR 1,800 feet), or (with Autopilot or FD or HUD, RVR 1,800 feet)Category II DH 100 feet and RVR 1,200 feet (with autoland or HUD to touchdown and noted on authorization, RVR 1,000 feet);Category IIIa No DH or DH below 100 feet and RVR not less than 700 feetCategory IIIb No DH or DH below 50 feet and RVR less than 700 feet but not less than 150 feetCategory IIIc No DH and no RVR limitation.http://www.faa.gov/a...ubs/AIM/aim.pdfCategory IIIc rtequires guidance alonmg the runway after touchdown.

I know that I'm drifting a little of course here but I didn't know that FAA asks for RVR24 on CAT I.Here, for Non-Commercial operators TC asks RVR12 which is kind of stupid and I've never understood very well, because the Aerodrome Operating Restriction (visibility) states that you need RVR26 (1/2sm) visibility unless the airport has special procedures.So basically, If you have RVR12 and you elect to land and the aerodrome doesn't have special procedures (which is the case for the majority of them) you are $crewed.Go figure...regards,Igor

The categories are:Category I Decision Height (DH) 200 feet and Runway Visual Range (RVR) 2,400 feet (with touchdown zone and centerline lighting, RVR 1,800 feet), or (with Autopilot or FD or HUD, RVR 1,800 feet)Category II DH 100 feet and RVR 1,200 feet (with autoland or HUD to touchdown and noted on authorization, RVR 1,000 feet);Category IIIa No DH or DH below 100 feet and RVR not less than 700 feetCategory IIIb No DH or DH below 50 feet and RVR less than 700 feet but not less than 150 feetCategory IIIc No DH and no RVR limitation.http://www.faa.gov/a...ubs/AIM/aim.pdfCategory IIIc rtequires guidance alonmg the runway after touchdown.

My figures are of course for Europe not N.America. Bear in mind that CAT IIIa & CAT IIIc are rarely used, if at all!vololiberista

My figures are of course for Europe not N.America. Bear in mind that CAT IIIa & CAT IIIc are rarely used, if at all!vololiberista

In Europe (the EU) the definitions are: Category I operation is a precision instrument approach and landing using ILS, MLS or PAR with adecision height not lower than 200 ft and with a runway visual range not less than 550 m. Category II operation is a precision instrument approach and landing using ILS or MLS with:(i) A decision height below 200 ft but not lower than 100 ft; and(ii) A runway visual range of not less than 300 m.Category III A operation is a precision instrument approach and landing using ILS or MLS with:(A) A decision height lower than 100 ft; and(B) A runway visual range not less than 200 m.Category III B operation is a precision instrument approach and landing using ILS or MLS with:(A) A decision height lower than 50 ft, or no decision height; and(B} A runway visual range lower than 200 m but not less than 75 m.EU-OPS, Subpart E (All Weather Operations) Ops 1.430, Appendix 1 (New), paragraph (e).http://eur-lex.europ...001:0238:EN:PDF

So does this AP-assisted ILS approach work in real life? (radios, OBS, NAV, APP) Or is that just an oversimplification of the real procedure?Also, how many categories of ILS does FS9 model? Replies from IRL pilots only, please!

So does this AP-assisted ILS approach work in real life? (radios, OBS, NAV, APP) Or is that just an oversimplification of the real procedure?Also, how many categories of ILS does FS9 model? Replies from IRL pilots only, please!

(1) Yes, more or less, in terms of the aircraft systems used to acquire an ILS and fly the approach, although in real life flying a higher-category ILS approach demands multiple autopilots and radio altimeters. Where it falls down a bit is with the default ATC, which for instance doesn't allow for STARs (standard approaches to an airport, which end in an ILS approach if available) or holds and speed restrictions, which real-life ATC will commonly give to maintain spacing between landing aircraft. (2) All FS9 ILSs are the same, except that some have a coupled DME and some don't, and the glideslope angle can vary (try EGLC - London City - for an approach with a realistically steep glideslope). There's no modelling of different ILS categories AFAIK.

(2) All FS9 ILSs are the same, except that some have a coupled DME and some don't, and the glideslope angle can vary (try EGLC - London City - for an approach with a realistically steep glideslope). There's no modelling of different ILS categories AFAIK.

None at all!! The ILS appraoch models also may not be accurate in the SIM in terms of heading, angle of approach etc. So check out the destination airport with afcad2 so that you can adjust add or correct.As far as FS9/FSX ATC goes it's a joke. Better to not use it at all. PFE and RC4 at least allow you to fly a SID/STAR and then make an approach according to the published approach plate.vololiberista

As far as FS9/FSX ATC goes it's a joke. Better to not use it at all. PFE and RC4 at least allow you to fly a SID/STAR and then make an approach according to the published approach plate.vololiberista

Please give FS9 ATC a break please. I have no problem using it to fly a SID/STAR and then make an approach according to a published plate. :NerdSure it should have been improved for FSX but that's not my problem. :( But I can update my FS9 STAR's and more so I am happy...... scrub that .... very happy! :Party:Edit* I have just written a new STAR for my next video flight EDDP/HLLT. You will see FS ATC instruct me perfectly.TOD at the correct time....I let FS ATC know I am flying an ILS approach and which STAR .....FS ATC will then follow me and give me the correct altitude for my FAF. I finally contact the tower when I am established on the ILS..... Perfect! :(

None at all!! The ILS appraoch models also may not be accurate in the SIM in terms of heading, angle of approach etc. So check out the destination airport with afcad2 so that you can adjust add or correct.As far as FS9/FSX ATC goes it's a joke. Better to not use it at all. PFE and RC4 at least allow you to fly a SID/STAR and then make an approach according to the published approach plate.vololiberista

Completely agree that those addons fix some of the problems, although for novice users the default does at least give a general if simplified sense of how ATC works. But even with PFE / RC you won't be able to replicate different ILS categories, which is what the OP asked. For one thing, you'd need FS to understand and use different approach minima for differently-equipped aircraft, which AFAIK it can't, even with PFE/RC. And on the ground, higher categories use holding points further back from the active runway, to avoid possible interference with the ILS signal. No way of modelling that unless you want a long queue of AI traffic that never moves...

Why would you need multiple autopilots?And in pictures I've seen of real Boeing 747, 737, 777 autopilots, they have something called VNAV and LNAV holds. Is the FS2004 Nav hold the same as LNAV in real life?PICTURE NOT MINE: Delta 777 MCP. LNAV and VNAV are by the IAS indicatorhttp://www.flickr.com/photos/7702824@N03/3885482426/#/photos/flightblogger/3885482426/lightbox/And pardon the noob question, but what are SIDs and STARs, and what do they do? Are they the same thing as approach plates? Also, what is RNAV?

(1) Yes, more or less, in terms of the aircraft systems used to acquire an ILS and fly the approach, although in real life flying a higher-category ILS approach demands multiple autopilots and radio altimeters. Where it falls down a bit is with the default ATC, which for instance doesn't allow for STARs (standard approaches to an airport, which end in an ILS approach if available) or holds and speed restrictions, which real-life ATC will commonly give to maintain spacing between landing aircraft. (2) All FS9 ILSs are the same, except that some have a coupled DME and some don't, and the glideslope angle can vary (try EGLC - London City - for an approach with a realistically steep glideslope). There's no modelling of different ILS categories AFAIK.