PPRuNe Forums

Go Back   PPRuNe Forums > Flight Deck Forums > Tech Log
Forgotten your Username/Password?

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


Closed Thread
 
Thread Tools
Old 20th Feb 2002, 14:24   #1 (permalink)
 
Join Date: Oct 2000
Location: in the air
Posts: 4
Question RA or DH?( a320 FMGS approah page)

Hi, I fly A321 as a F/o.. .my company start to apply CAT II approach on a321.. .I checked fcom4 for CATII approach.. .They only say 100 above DH.-100 above minimum. .at DH-minimum.. .but on the CAT II approach chart,there are 2 minimums,RA & DH.. .what should I insert in FMGS DH field?
flyjet is offline  
Old 20th Feb 2002, 16:15   #2 (permalink)
 
Join Date: Dec 2001
Location: Bed
Posts: 23
Thumbs up

Check S.O.P's FCOM 3. Hopefully your company have issued you a section on LVO.

However, in the mean time use MDA for Non precision & Cat I, DH for Cat II & III(A&B).

Hope that helps.
Flex33 is offline  
Old 20th Feb 2002, 17:53   #3 (permalink)
 
Join Date: Nov 2001
Location: Kagerplassen
Posts: 224
Post

I read your question not as to where to enter your value... You only fill out the DH-field during a lovis-approach, as already stated, and use the MDA-field for everything up-to-and-including-CAT1.

But if given 2 different values, a DH and a RA, I would fill in the RA-number in the FMGC, because the a/c will generate an autocallout at minimum, based on your radio-altimeter, not your baro-altimeter.

Hope it helps!

[ 20 February 2002: Message edited by: Pegasus77 ]</p>
Pegasus77 is offline  
Old 20th Feb 2002, 20:46   #4 (permalink)

Dog Tired
 
Join Date: Oct 2001
Location: uk
Posts: 1,394
Angry

pagasus..not true. it is a customer pin-programme which determines callouts.. .for cat1 and non prec you must use the baro therefore insert in 'mda'. it is really a 'da' we are using but we won't quibble.. .for cat 2 and 3 the decision is based upon rad alt therefore the dh (for it is a height) is inserted in 'dh',not 'mda'. <img src="tongue.gif" border="0">

[ 20 February 2002: Message edited by: fantom ]

[ 20 February 2002: Message edited by: fantom ]</p>
fantom is offline  
Old 20th Feb 2002, 21:10   #5 (permalink)
 
Join Date: Nov 2001
Location: Kagerplassen
Posts: 224
Post

If what you say is true, then Flyjet should read his own AOM, to find out which input signal his company uses. My company anyway bases the callout on RA, therefore I type in the RA-minimum from the chart in the FMGC.

Seems weird to me, if the minimum is based on RA as it is in lovis-approaches, to make the minimums-callout on baro-altitude??
Pegasus77 is offline  
Old 20th Feb 2002, 21:45   #6 (permalink)

Dog Tired
 
Join Date: Oct 2001
Location: uk
Posts: 1,394
Wink

well spotted peg.. .the minimum is based on either, but for low vis the rad alt is close enough to the runway (or flat surface) to be useable. at points further out (like cat 1) you can not use the rad alt because of the terrain.you therefore use a DA for cat 1 (by which point the decision has been made) and,if you go around, you fly so as not to violate the associated MDA.of course, our mcdu does not have a field for 'DA' so we use the 'MDA' one. it is,in fact a DA we are inserting.it follows that any DA is higher than its associated MDA because of the sink which occurs on the go around. <img src="tongue.gif" border="0">
fantom is offline  
Old 22nd Feb 2002, 02:24   #7 (permalink)
 
Join Date: Oct 2000
Location: in the air
Posts: 4
Talking

thanks for reply.. .all of your comment are very helpful for me!!!!
flyjet is offline  
Old 22nd Feb 2002, 07:45   #8 (permalink)
 
Join Date: Jan 2000
Location: USA
Posts: 165
Post

I think it depends on what your company ops allow. We use MDA for non-prec and Cat I. The DH block is used for CatII and CatIII. We us NO DH for the Cat III, and an alert height of 100"RA, on CatII it depends if RA is authorized or not. If it is authorized we put that figure in the DH and call mins off of the RA or Inner Marker, whichever occurs first. If the RA is not authorized we use the MDA block, and call mins off of Barometric or Inner Marker whichever occurs first.
Iceman49 is offline  
Closed Thread
 
 
 


Thread Tools


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



All times are GMT. The time now is 05:39.


vBulletin® v3.8.7, Copyright ©2000-2014, vBulletin Solutions, Inc.
SEO by vBSEO 3.6.1
1996-2012 The Professional Pilots Rumour Network