Originally Posted by
dream747
Guys thanks for the discussion.
Is there anywhere at all we can get a copy of any document that explains what logic does the EFB calcuLates its figures on? Like he no reverser credit on dry runways.
The requirements set out for the calculation of take off performance are regulatory and should be contained in your company OMB and aircraft FCOM.
With TMAXFLEX you are calculating the maximum theoretical outside temperature for which a takeoff can be safely achieved and reducing the thrust output accordingly. If you're unable to alter that value, you can artificially alter the environment to create conditions which favour higher thrust.
Personally I have not reduced runway length to do so, however I frequently factor in a nil headwind or slight tailwind in order to "worst case" things. I've found even a slight tailwind has a significant impact on the takeoff performance, given the factorisation.
In addition we regularly use intersection departure calculations even when departing from full length.