Question with Flex temps

[Guest aviacion4]

Hi thereI was wondering if by any chance you know the formula, used in real life to calculate according to te tempeture, rwy lenght, field alttitude , etc, for getting the correct tempeture to be entered in the perf page. I read in a post that by error, we are supposed to insert the temperatures with a - (-42) for it to have effect, but i still don't know where to get the tempeture....thankshappy holidays

[Guest vrandar]

The formula is complex and there is a very big Airbus document called "Getting to Grips with Cost Index" which discusses it (see http://www.wingfiles.com/ for a copy).For the MCDU the thrust you should get at different minus Flex TO Temps is shown below. Make sure you never choose a temperature which is less than 75% of TOGA thrust.FLEX N1%-10 96.1-11 96.0-12 95.8-13 95.6-14 95.5-15 95.3-16 95.2-17 95.0-18 94.9-19 94.7-20 94.5-21 94.4-22 94.2-23 94.1-24 93.9-25 93.8-26 93.6-27 93.5-28 93.3-29 93.1-30 93.0-31 92.8-32 92.7-33 92.5-34 92.4-35 92.2-36 92.1-37 91.9-38 91.7-39 91.6-40 91.4-41 91.3-42 91.1-43 91.0-44 90.8-45 90.7-46 90.5-47 90.3-48 90.2-49 90.0-50 89.9-51 89.7-52 89.6-53 89.4-54 89.3-55 89.1-56 88.9-57 88.8-58 88.6-59 88.5-60 88.3Rob Elliott, EGPE InvernessPSS Airbus Support andAirbus Fleet Training Captain, British Airways Virtual airbus@speedbirdonline.co.ukhttp://www.speedbirdonline.co.uk/airbus.htmlhttp://www.bavirtual.co.uk