ATM + Derate 737
when using a combination of fixed derate and assumed tepmerature reduced thrust how can I determine the best combination ?
I've always assumed that (B737NG in mind) derate 2 plus ATM would provide the max savings, but shouldn't that be reflected in the takeoff N1 being reduced ?
most of the time a no derate ATM takeoff is very close to a derate 2 + ATM N1 value .... how is that possible ?
so a more concise question: when using ATM (Flex) as a method for reduced takeoff power, is the N1 value that results the only indication of how effective it is ?