Airbus Flex/Boeing ATM Take offs
 

So I'm trying to understand this in a better way, and was wondering if anyone could point me in the right direction.

For example, I understand how both of these methods work, but does the EPR/N1% remain the same.

For example

I'm undertaking a Flex/ATM takeoff, at Temp 40c (OAT 25C) for example, on take off the N1% still rises to around 105+, which is roughly the same as TOGA, if somewhat slightly less.

Do the numbers EPR/N1% numbers remain the same no matter what take odd procedure your using, but the thrust produced is less? Or would the EPR/N1% number be less on take off if you were on Flex/ATM.

Hope this makes sense? Will try and clarify better if I need to?

CTA

Assuming normal engine status, condition etc.: N1/EPR is a direct indication of the thrust the engine is producing.

So on flex/assumed temperature takeoff, thrust produced by the engine is reduced and N1/EPR would be lower accordingly.

Check T. REF for your flat rating engine. Probably you're closer than you think. That maybe why.

N1 is reduced with the user of a higher assumed temp (737). It's not uncommon to see takeoff N1 as low as 88% or so.