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Guest nirvana

CAT I, CAT II, CAT III ?!?!?!?!?

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hey folks!could anybody tell me what CAT I/II/III means? i've never been interested in airport signs and stuff but now I WANNA KNOW WHAT THIS MEANS!!! :) thank you!regards :-wave===========>peter

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Peter,I'm assuming you are referring to ILS minimums. Here is an excerpt from the Aeronautical Information Manual that should answer your question. This is from Chapter 1 Section 1-1-9(i).__________________________i. ILS Minimums 1. The lowest authorized ILS minimums, with all required ground and airborne systems components operative, are: (a) 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); (:( Category II. DH 100 feet and RVR 1,200 feet; © Category IIIa. No DH or DH below 100 feet and RVR not less than 700 feet; (d) Category IIIb. No DH or DH below 50 feet and RVR less than 700 feet but not less than 150 feet; and (e) Category IIIc. No DH and no RVR limitation. NOTE-Special authorization and equipment required for Categories II and III. MIke

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I will go ahead and add to what Mike says. In very general terms:CAT I is the basic ILS. It'll line you up with the runway, but it's not accurate enough that you can auto-land. That's why you need reasonable visibility and a fairly high DH. You aren't going to land in bad weather or 0 vis. All the runways in FS are Cat I, regardless of what they're supposed to be.CAT II has a slightly tighter beam and the equipment can get you to the runway better, but you still can't land in 0 vis, although bad weather landings are slightly more possible. there are some auto-land CAT II aircraft, but it's still up to the pilot to pay attention. So certification is required.CAT III has multiple beams, and you can go ahead and take a nap at the stick, because the equipment can now auto-land. CAT III will take you dead on the centerline and touchdown right at the markers. You can now land in 0 vis, but taxiing is a different story. The aircraft and crew need to be CAT III certified to get into a CAT III facility in bad weather and 0 vis. The reason isn't because it's more difficult, it's because with this capability doing a blind landing requires some certainty the crew knows what they're doing.GV - this is a special category of it's own. The Gulfstream V has FLIR, so there's always visibility. It also has a computer rendition of the terrain and what's in front of you. GV's, needless to say, are CAT IIIc certified.That's the layman's ILS Category system.

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This all reminds me of something I saw on late nite TV about a month ago... It was the Letterman show I think and Tom Cruse was the guest. Letterman ask Cruse something about his getting into flying.. To which Cruse replied with much exitement that he had, and had just gotten his instrument rating in Italy... He went on to decribe the small italian plane they had used.... Nothing out of place up to here right but at this point Cruse with great excitement pointed out the weather was 00... And I thought to myself "I should have been so lucky when I got my instrument to have gotten the rating and a Cat III at the same time..." Maybe they do things different there... But I got a good laugh out of it anyway...Ron Mashburn

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I never quite understood why it says CatII etc. on the runway signs when tou are turning onto the runway, because you are after all about to take off, not land.

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I am just wondering, what is the difference between GV and CAT IIIC?JimCYWGPS Anyone from CYWG here. I was at the airport on Monday August 5th and there was a older 747 on the tarmack. No marking and it had some blue in it. Anyone know anything about it.

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Oyvindshansen,These are often used at the ILS critical areas. I believe that different categories may have different critical areas. I'll look it up!Regards :-waveJonathanReal World PilotComair/JU

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Also a Gulfstream V with the Kollsman All Weather Window retrofit is certified to land in CAT III conditions on a CAT II runway.Regards :-waveJonathanReal World PilotComair/JU

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Also, CAT II & III require special certifications by the pilot (normally applies to ATP pilots) & aircraft in order to use those minimums. When I flew for the airlines, I had to get a certain amount of flight time in the TYPE of aircraft that I was flying in addition to an IFR check every 6 months at the new minimums (Decision Height for the ILS) in order to be able to legally land using the lower CAT I/II/III minimums. CAT I/II/III state visibility minimums that must be met in order to land on an ILS approach instead of going missed.Normally the CAT II/III approaches are used by the airlines and only at airports certified for these approaches. Part 91 operators (non-commercial) MUST use the published normal minimums on the approach plate.Just some more info about the CAT I/II/II certifications.Scott :-)

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Jim,As Jonathan said, with the right equipment a GV can land in 0 vis on a CAT II runway. This is because the GV can "see" the runway well enough to perform a nearly flawless landing in any weather, day or night.The reason I list a GV as a special category is because of the HUD, FLIR, and (I forget the official name) the ability to draw the scene in front of you.The are now a couple other aircraft with this capability, but it's all the same as military jets fully decked out with all kinds of night optics, infra-red optics, terrain-following radar, and just about anything else one would need to see on a dark and stormy night.I'll see if I can get a pic of the HUD in action.CAT III planes by definition can land on CAT II runways, but the GV can do this with auto-land. It's a big reason it costs 42 million bucks.

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thank you guys!! i didn't know about this ils-cat-stuff! :) though it's a little bit confusing with the signs on the taxiway! you've to be VERY low to see em! :-hah okay, once more: thank you!greetings :-wavepeter

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