I think that
John_T's last post should be made into a sticky!!!
Mind you, in doing so, it would reduce performance related discussion in this forum to about 20%, spoil a lot of lively discussion......
Seriously, if any PPRuNers had any doubts of the how, when, where or why of Thrust Ratings, Derates, Reduced Thrust (ATM or Flex), then it's cut and paste time for
J_T's post,
starting with a LOT of Instructors (who are, after all, mandated to pass on such knowledge).
Regards,
Old Smokey