PPRuNe Forums - View Single Post - Some doubts from "Ace the Technical Pilot Interview".
Old 16th Sep 2010, 01:33
  #26 (permalink)  
ImbracableCrunk
 
Join Date: Oct 2006
Location: Ankh Morpork, DW
Posts: 652
Received 0 Likes on 0 Posts
jimmygill wrote:

De-Rating

This is not an actual reduced thrust takeoff. I listed here to remove confusion. De rating is done to by maintenance staff to limit maximum thrust, for example from 25kn Flat Rating to 23 kn De-rated thrust, this can be done for several reason, such as engine life and making two slightly different engines have same thrust. Pilot cannot control this during flight or take-off.
Uh-oh! Then what have I been selecting in the 737 when I select a derate of 24k or 22k? And I'm not an engineer/mechanic - I hope I'm not in trouble!



I'm open to corrections, but derates and assumed temps can be used combined or separately. The max assumed temp is 75% of the rated thrust. If you only need 60% of 27k, you can derate to 24k and assume 85%. (Or something along those lines.)

All selectable from the safety and comfort of the cockpit. No plug changing required.
ImbracableCrunk is offline