Originally Posted by
Banana Joe
The maximum rated thrust is the maximum thrust the engine is capable of delivering with the thrust lever at the forward stop and you would use it only if terrain contact is imminent in the GPWS and Windshear escape maneuvers. And I would guess it's also more than 27K bump.
Not quite. Max rated thrust (for the ambient conditions) is achieved with the thrust lever ~2 degrees short of the forward stop. In those last two degrees of throttle travel, you get what is known as 'headroom' - basically limited overboost. Headroom is to account for various tolerances and to make sure you can always get full rated thrust. It depends on the specific conditions, but headroom is usually between about 0.5% and 1.0% N1 (figure roughly twice that amount of thrust).
The max rating available for the CFM56-7 on the 737-800 is less than the max rated thrust the engine is capable of (used on the -900ER). On the shorter 737-6/7/800 models, the max ratings are lower to account for the ability of the tail to counter the thrust pitch-up (shorter aircraft means less moment arm for the tail surfaces). On the non-FADEC 737-300/500, this thrust limit was via a physical block in the throttle - on the FADEC NG this is done with a rating plug on the FADEC.