PDA

View Full Version : CAT III and CAT 3(A320)


320p
29th Oct 2007, 15:17
Hi,

As I understand CAT I,II,III indicates approach category (dependent on Ground installation) whereas CAT 1,2,3(Dual or Single) indicates Aircraft FMGS capability.

My Question is:

(a) Can we plan for CAT III auto approach and auto landing with CAT 3 single indicated on the FMA.(FCOM3.01.22 P3 does indicate so). If YES is the Requirement for CAT 3 Dual a company requirement).

(b) Is there a tendency in airbus FCOM to interchange landing category between CAT III and CAT 3 as indicated on FCOM 4.05.70 P 16, last column regarding LANDING CATEGORY. Similarly, on 4.05.70 P18, it indicates LOSS OF CAT III (clic clic clic) and P19, where it says LOSS of CAT3 (clic clic clic).

Thanks
320 P

loc22550
29th Oct 2007, 16:39
320p,

A)Indeed you can perform an Autoland with Cat 3 single display on FMA,even CAT2, (autoland is not permited only when CAT 1 is diplay on FMA):But this.. is for the A/C capability only...Now off course you need to have the adequate weather minima as well.
In order words:
-Doesnīt mean that if you have cat2 on FMA you can perform an CATIII approach with Autoland,of course not,you are limited to a CATII approach,By the CATII DH you must have the visual reference to continue.(manual or automatic)
-Cat3 single display on FMA allows you to perform an approach with a minimum DH of 50' (CatIIIA,CatII, CatI wx condition...).
-Cat3 dual display on FMA allow you to perform an approach without DH. (CATIIIB wx).

Well thatīs the only think i can tell you according my limited knownledge..
Hopefully a LVP specialist will give you more infos.

320p
29th Oct 2007, 17:04
Thanks loc22550,

My apologies!I should have mentioned weather minima as per the Approach Category being fulfilled.
My querry was primarily aimed at the Autoland part and the FMGS landing capability indicated.

pullup hard
29th Oct 2007, 18:01
320 p,
the respective Minima go together with your landing capability:
Cat3 Single will allow you a Min of 50ft/ 200m RVR (-->CAT3a airfield Installation)
Cat3 dual will allow you a Min of 15 or "NO" and 125 m RVR (-->Cat3b airfield)
Loss of Cat below 1000ft Ra ( triple click) will in any case lead to a go-around unless you have visual clues to continue or it has happened below alert height (=200ft-->inhibited)

Should be clear as mud now...:)
PUH

loc22550
30th Oct 2007, 04:14
May be wrong but i think AH (alert Height) is 100 feet on A320, (200feet on A330).
Cheers