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

320 IAE EPR rating limit changes during T/O

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

320 IAE EPR rating limit changes during T/O

Old 18th Sep 2012, 21:17
  #1 (permalink)  
Thread Starter
Join Date: Apr 2009
Location: Canada
Posts: 608
Likes: 0
Received 0 Likes on 0 Posts
320 IAE EPR rating limit changes during T/O

With regard to the EPR rating limit on the E/WD during T/O on the 320 series V2500. I've noticed that the engines quickly race up to the initial flex EPR rating limit but once there the limit then increases further before finally settling down at one number. It's quite tricky when trying to judge whether the engines are stable and when T/O thrust has been set.

Two questions:

1) Why does this happen? Is it to ensure engine parameters are stable at a relatively high setting (but not entirely at full T/O power) before FADEC sets final power? Saving engine life? Or could it be that at the calculated EPR rating limit the desired thrust has not been obtained and the EPR must increase to meet required thrust.

2) When is "thrust set"? As PNF, and having to make this call before 80kts, I find it hard to judge. If thrust is set when the engines have fully stabilised at max EPR rating limit then with the changes it's very close to 80kts if not after.

Last edited by Airmann; 18th Sep 2012 at 21:23.
Airmann is offline  
Old 18th Sep 2012, 23:32
  #2 (permalink)  
Join Date: Aug 2003
Location: <60 minutes
Posts: 111
Likes: 0
Received 0 Likes on 0 Posts
1. Usually on turbofan, FADEC controlled engines, this shift in EPR or N1 ensures the EGT/ITT margin between that required for the calculated thrust and MAX egt is maintained, all the way from static application of power with no ram air effect all the way to V2. Helps extend engine life without compromising the thrust you need for takeoff on X length runway.

2. All engines EPR/N1 have reached thrust command bug. Anything after the associated thrust set call is scheduled by FADEC or a failure/stall/surge. Use the time between 'set' and V1 to monitor everything else!!

In other words, has the engine reached the commanded thrust by setting the thrust lever in the gate?

Last edited by darkbarly; 18th Sep 2012 at 23:39. Reason: typo
darkbarly 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.