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

α prot = α max

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

α prot = α max

Thread Tools
 
Search this Thread
 
Old 12th May 2009, 09:48
  #1 (permalink)  
Thread Starter
 
Join Date: Jul 2007
Location: The Netherlands
Age: 40
Posts: 81
Likes: 0
Received 0 Likes on 0 Posts
α prot = α max

Hey there,

The airbus in normal law:
At take off, alpha prot. is equal to alpha max for 5 seconds.

The only possible answer I can come up with is that (A320) these 5 seconds are for the transition form ground mode (direct law) to flight mode (normal law). Studying the A330 now, I have learned that this transition takes at least 10 seconds (pitch law), meaning that my above possible answer is not valid here.

Any comments will be appreciated.
zonnair is offline  
Old 12th May 2009, 12:10
  #2 (permalink)  
Thread Starter
 
Join Date: Jul 2007
Location: The Netherlands
Age: 40
Posts: 81
Likes: 0
Received 0 Likes on 0 Posts
Anyone, with the knowledge???
zonnair is offline  
Old 13th May 2009, 13:56
  #3 (permalink)  
 
Join Date: Jan 2005
Location: W of 30W
Posts: 1,916
Likes: 0
Received 0 Likes on 0 Posts
So much happening in the very early and late stages of each flight but minimum detail in the documentation.
You may have some more by directly questioning Airbus through your operation department ...
CONF iture is offline  
Old 13th May 2009, 15:12
  #4 (permalink)  
 
Join Date: Aug 2006
Location: Sri Lanka
Posts: 41
Likes: 0
Received 0 Likes on 0 Posts
The diagram in FCOM 1.27.20 page 1 for the A330 indicates the transition period from ground mode to flight mode in normal law as 5 seconds.
However I am not current on the A330 anymore and maybe there is a newer revision than the one I have.
As said earlier the best thing would be to contact the manufacturer.
ALK A343 is offline  
Old 13th May 2009, 16:23
  #5 (permalink)  
6f1
 
Join Date: Aug 2007
Location: The back of beyond
Posts: 39
Received 0 Likes on 0 Posts
6f1

Yes that is correct alpha prot =alpha max for 5 secs for the A330 Fcom1-27-20 pg 4.
White mans magic I think !!!

Last edited by 6f1; 13th May 2009 at 16:44.
6f1 is offline  
Old 14th May 2009, 06:10
  #6 (permalink)  
 
Join Date: Sep 2003
Location: Dunnunda
Posts: 496
Received 8 Likes on 3 Posts
With Alpha-Floor engaging sometime between Alpha Prot and Alpha Max, I dare say if they didn't keep those figures the same for 5 seconds there would be a few people conducting max rate takeoffs.

Considering it is only V2 that has to be 1.13 VS.

Vr's only requirements are that Vr is > 1.05 Vmca and it also allows V2 to be reached by 35 feet.
Bula is offline  
Old 14th May 2009, 16:01
  #7 (permalink)  
Thread Starter
 
Join Date: Jul 2007
Location: The Netherlands
Age: 40
Posts: 81
Likes: 0
Received 0 Likes on 0 Posts
Thanks CONF iture:
I was thinking of that too. They might come with a possible answer.

ALK A343 and 6f1:
That are most probably old fcoms then (or 320). According to the table in my FCOM. The transition from ground to flight mode takes 8 seconds for pitch law, which will start after the 2 seconds transition in lateral law.

I'll post Airbus answer.
zonnair 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



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.