Crossunder - try
http://www.pprune.org/forums/archive...p/t-10159.html - I found this through Google in the archive. It covers most of the good points.
One issue that seems to pop up now & then is engine deterioration. Using EPR (assuming it's properly calibrated) then EGT/TGT will gradually creep up to produce the same rated thrust after a few thousand hours.
With N1 management, two things happen as the engine deteriorates: The fan airfoils lose a bit of efficiency so they pump less airflow at the same N1, but the core runs a bit hotter to drive the fan. Thus fan thrust drops a bit, but core thrust increases a bit, and they effectively balance each other.
For a bit of education, check out the MEL for TO thrust-setting procedure if your primary thrust gage (N1 or EPR) goes dead.
