Go Back  PPRuNe Forums > Flight Deck Forums > Tech Log
Reload this Page >

Cat III approaches?

Tech Log The very best in practical technical discussion on the web

Cat III approaches?

Old 11th Sep 2000, 16:51
  #1 (permalink)  
Posts: n/a
Question Cat III approaches?

Read the article in 'Pilot' a few months ago about autolands in bad weather. Could someone please tell me;

Which aircraft are cat II equipped and which aicraft are cat III equipped?

As an occasional S.L.F., I would like to get to desination inspite of fog and not divert!

I always thought that cat IIIB was 14ft decision height and Cat IIIC was 0ft. Read this somewhere. Can someone please enlighten me?
Old 11th Sep 2000, 22:50
  #2 (permalink)  
Posts: n/a

Briefly.. (As a guide only...)

CAT I - 200ft and 550m Visibility
CAT II - 100ft and 300m
CAT IIIa - 50ft and 200m
CAT IIIb - Below 50ft (e.g. 744 and 75/76 have no decision height, they decide once on the ground)


CAT I - any basic aircraft in the world with an ILS receiver and a half competant pilot.
CAT II - 146, some OLD 737-200
CAT IIIa - 737-200ADV, all newer 737, Avro RJ
CAT IIIb - 747, 757, 767, 777, A320 etc etc

Old 11th Sep 2000, 22:51
  #3 (permalink)  
Posts: n/a


As a matter of fact it is not only the aircraft type that does it. The type is where it starts. My 737-3/400s are CAT IIIA. this was at first a surprise to me but it works OK.
Now this stuff needs maintenance so the local authorities are supposed to keep a close eye on the maint procedures.
Once you have a properly equipped and maintained aircraft you need CAT III trained pilots. This is a training and experience thing on top of the standard IF rating.
Of course you can't autoland if you don't have a proper ILS. Similarly you can't fly CAT I, II, IIIA, B or C if the ILS is not at least qualified accordingly.

That is the chain. One link breaks and you are back redoing your fuel calculations.
Old 12th Sep 2000, 01:46
  #4 (permalink)  
Mr Benn
Posts: n/a

And finally, it also need the airport/runway to be equipped. Most of the major airports have suitably equipped runways, and of course wind is not normally a factor, being that its normally mist or fog that causes the conditions to be Cat 3, for which there needs to be not much wind.
Not all destinations are Cat 3 certified.
So you need - aircraft fully serviceable and operating to Cat 3, crew fully certified and current, airport and more specifically runway, equipped.

By the way, just to add, Cat 3b is lower than 50 feet (often zero feet) and 75m viz (so's you can taxi the thing once you are on the ground).

Old 12th Sep 2000, 12:51
  #5 (permalink)  
Two Bars
Posts: n/a

Also, CAT I, II & III are not mutually exclusive. If an aircraft is engaged on a CAT III approach and an aircraft component fails, it may be possible to revert to CAT II procedures.
Old 12th Sep 2000, 20:11
  #6 (permalink)  
Posts: n/a

You need :A/C Certified
Crew Cerified
Airport Certified
WX within A/C and or state limits

Cat III is generally only found in Europe, Nth America, and Japan. (standing by for corrections)
Old 13th Sep 2000, 15:23
  #7 (permalink)  
Posts: n/a
Thumbs up

Thanks a lot chaps - very informative

I presume all glass-cockpit jets (737-300, 757, A320 etc) are all autoland capable within the caveats you all mention?

I can't really imagine any airline not having this capability - noone would fly with them in bad weather! But are there any?
Old 13th Sep 2000, 15:55
  #8 (permalink)  
Two Bars
Posts: n/a

In QANTAS, the 747-200 is certified to CAT II minima only, while the 747-300 is certified to CAT IIIA criteria. Both aircraft are not "glass" and both are approved for autoland operations.
Old 13th Sep 2000, 21:56
  #9 (permalink)  
Posts: n/a

Of course, you could rush out and buy a hugely expensive Head Up Display, assuming that the CAA will let you play with your new toy before it becomes obsolete!

PS Most modern turboprops are Cat 2 capable.

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.