US Patent 9205927 Aircraft environmental control system inlet flow control

A system and method for controlling bleed air flow into an air cycle machine that includes a bleed air inlet and a conditioned air outlet is provided. The system and method include discharging bleed air from an operating gas turbine engine, sensing exhaust gas temperature (EGT) of the gas turbine engine, sensing conditioned air temperature at the conditioned air outlet, and controlling bleed air flow into the air cycle machine based on the sensed EGT and on the sensed conditioned air temperature.