Abstract: This invention serves to improve augmentor effectiveness of a turbine fan engine that has a bypass airstream and a core stream by synthesizing signals indicative of both the airflow of the bypass stream and core stream and directly scheduling fuel/air ratio for both streams and ascertaining the desired fuel flow to be used to meter fuel to each of the streams.

Abstract: Sensed engine inlet temperature is utilized to detect compressor surge whenever its computed temperature rate of change or rise signal exceeds a predetermined value. This signal may be coupled to another engine operating parameter, such as rotor speed, compressor discharge pressure and the like and permutations thereof, to guard against false detection. Engine inlet temperature rate of change or rise is an efficacious surge detection parameter particularly when an afterburner is used inasmuch as the hot gases of the afterburner will have a significant influence on the engine inlet temperature sensor in a reverse flow situation making that signal a positive indication of imminent surge.

Abstract: A thrust augmented twin spool turbofan engine system to control instability at high altitude, low Mach number conditions wherein an engine electronic control monitors engine inlet temperature, engine burner pressure and Mach number, and inhibits fuel flow to the outermost augmentor segment when the engine inlet temp drops below 25.degree. F, when engine burner pressure drops below 120 psia or when the Mach number drops below 0.4. When fuel flow to the outermost augmentor is inhibited, upmatch logic modifies the variable nozzle AJ trim signal closed 8% and the power level angle trim signal up 4.degree..