Originally Posted by
rudestuff
The engine derate will tell you the margin you have. Once the assumed temp reduces to ambient then the RTOW starts to drop.
Kind of, depending on if there are obstacles in the departure and where they are. It could be more to do with max continuous thrust (fixed) if the dominant obstacle is some distance away.
I find the weight margin, RTOW vs. ATOW, a better indicator of how close to the wire you actually are.