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

A330 v A320

Old 28th May 2014, 18:31
  #1 (permalink)  
Thread Starter
 
Join Date: Jan 2012
Location: Not far from the edge of the Milky Way Galaxy in the Orion Arm.
Posts: 510
Likes: 0
Received 0 Likes on 0 Posts
A330 v A320

In the A320 there are the FACS - among other things they perform characteristic speed computation -


In the A330 - the SECs provide this function but the SECs in an A330 are secondary computers whereas in the A320 the SEC is the Spoiler and Elevator Computer.


There are, in the A330, 3 PRIMS for Normal, Alternate and Direct control laws.


I thought most Airbuses are supposed to be the same?


Given the differences - what would the PRIMS be in the A320, if the A320 had PRIMs [ which they don`t have] (that was for the Pickier members) - ? Would they be the FACs, ELACs and the SECs? I am trying to find a sameness here.


Thank you for your time. I know many of you have moved to the A330 from the A320 - and as you guys can gather; I am on page one.
--and they have stuck the RAT on the Green (330) instead of the Blue (320) well standard then?
Natstrackalpha is offline  
Old 29th May 2014, 05:24
  #2 (permalink)  
 
Join Date: Jan 2014
Location: N5109.2W10.5
Posts: 720
Likes: 0
Received 0 Likes on 0 Posts
I am on page one.
Try reading something like:
http://www.davi.ws/avionics/TheAvion...ook_Cap_12.pdf

--and they have stuck the RAT on the Green (330) instead of the Blue (320) well standard then?
If you wanted to power all the ailerons (4) and both elevators, which system would you put the Rat on?
Goldenrivett is offline  
Old 29th May 2014, 12:16
  #3 (permalink)  
Thread Starter
 
Join Date: Jan 2012
Location: Not far from the edge of the Milky Way Galaxy in the Orion Arm.
Posts: 510
Likes: 0
Received 0 Likes on 0 Posts
Thank you Goldenrivett


-er, Green.
Natstrackalpha is offline  
Old 29th May 2014, 14:54
  #4 (permalink)  
 
Join Date: Mar 2012
Location: Having a margarita on the beach
Posts: 2,430
Likes: 0
Received 0 Likes on 0 Posts
Originally Posted by Natstrackalpha

In the A330 - the SECs provide this function
Hi,

The characteristic speeds are computed by the Flight Envelope (FE) of the FMGEC.
sonicbum is offline  
Old 30th May 2014, 18:49
  #5 (permalink)  
 
Join Date: Jul 2002
Location: UK
Posts: 3,093
Likes: 0
Received 0 Likes on 0 Posts
Originally Posted by Natstrackalpha
I thought most Airbuses are supposed to be the same?
The end functionality is supposed to be the same. The commonality is primarily at the end-user (i.e. pilot) level, such that the majority of conversion training is fairly minimal. The implementation at low-level is likely to vary, because of the different use case specification.

Regarding the A320/A330-340 differences, have a look at my late Prof's writeup on his visit to Toulouse in 1993:

Report on visit to Airbus Industrie - 28-29th Jan. 1993

As far as why the computers are set up slightly differently, look at this table:



I'm supposing that FCPC => PRIM and FCSC => SEC in the A340 nomenclature.

The PRIMs use an Intel 80386, which is a significantly more powerful piece of hardware than the Motorola 68k used in the ELAC of the A320. As I said in previous threads, for aviation applications the tendency is to use obsolete technology because the reliability has been practically proven. A move to a more powerful processor means that the main FC can shoulder a greater load and therefore a greater level of redundancy.

Regarding that, this blog post seems to confirm my theory:

Flight To Success: A320 verses A330 ... Fault Redundancy

The 330 is set up that each flight control computer can control ailerons, elevators, and some spoilers. All except for 1 can control the rudder. Not to forget there's a separate backup rudder control scheme, with its own generator and control computer.

The 320 can't make that claim. Additionally, on the 320, it's much easier to end up in Direct Law, and if you are in alternate law you are going to be without the autopilot…. I think in all cases, but not completely sure.

On the 330 the autopilot is often available in alternate law, and you don't automatically degrade to direct law from alternate law. The 320 almost always reverts to direct law from alternate law when the gear is lowered.
DozyWannabe is offline  

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.