We operate a mixed fleet of non Trent and Trent cored engines and haven't suffered ......yet! Although the engines have been derated to 'G' power on the 744, the 767 still operates at the 'H' rating.
The engines were derated to extend the life somewhat and most of the engines pulled have been for time-ex. One recent example though suffered a TOD surge but although the exceedance was within inspection limits the engine was pulled for LPT1 blade platform damage.
The engine has in the past suffered from compresor Metco lining loss, is this what you are refering too?
Look on the brightside though it only takes a couple of hours of change a Roller.........if you have a (complete!!!!) spare.
