Originally Posted by MaxFL360
so would i be correct in saying that the 115b is flat rated to 115000 lb/thrust although it theoretically is capable of much more if no limit was placed up to ISA+15?
That would be correct if the only limits to consider were gas temperatures and rotational speeds. There are other limits such as loads on bearings, shaft torques, carcass pressures that may impose an absolute limit on the allowable thrust.