Derated takeoff and heavy rain

[Guest pierre974]

Hi fellow captains,I wonder if it is possible to perform a derated takeoff (T01 or TO2) under heavy rain conditions, or is it mandatory to have full thrust available with continuous ignition under such bad weather ?Another question concerning derated T/O : is it possible to combine TO1 or TO2 mode with an assumed OAT, or do one has to choose between the regular T0 modes and the assumed temperatures given by the runway tables ?Thanks for your replies and have a good flight with PMDG :-sun1

[Guest Raphouille]

>I wonder if it is possible to perform a derated takeoff (T01>or TO2) under heavy rain conditions, or is it mandatory to>have full thrust available with continuous ignition under such>bad weather ?Hello,This is taken from the B747-400 takeoff data manual, but may be usedas a general ruleReduced Takeoff N1(EPR) should not be used when: