US Patent 10451491 System and method to determine total air temperature from turbofan bypass flow temperature

A system and method for calculating aircraft total air temperature from bypass flow temperature in a turbofan gas turbine engine having a bypass flow duct includes sensing aircraft speed (M), sensing engine fan speed (N1), sensing core engine speed (N2), and sensing bypass air flow temperature (T15) in the bypass flow duct. Total air temperature (TAT) is calculated as a function of the sensed aircraft speed, the sensed engine fan speed, the sensed core engine speed, and the sensed bypass air flow temperature. In some embodiments, fan bleed airflow is determined, and a correction is applied to the sensed bypass airflow temperature, and aircraft total air temperature (TAT) is further based on the corrected bypass airflow temperature.