For correct and wide application of reduced thrust takeoff technique, the temperature
characteristics ofhigh bypass ratio turbofan engines and the takeoffperformance of large aircraftswere
analyzed. Assumed temperature is the equivalent ambient air temperature determined by the actual
takeoffmass ofan aircraf.t The necessary conditions ofreduced thrust takeoffare that the actual takeoff
mass is less than themaximum takeoffmass of an aircraft and that the assumed temperature is higher
than the reference temperature. The rotation speed of the fan under assumed temperature reduced
thrust takeoff is calculated based on the analogical condition of engine.