Question

The response of a jet engine thrust to the throttle angle is instantaneous.

(a) True

(b) False

This question was posed to me in examination.

Origin of the question is ILS/MLS Coupled Landing System and Automatic Landing in chapter Autopilots and Flight Management Systems of Avionics

Answer 1

Right choice is (b) False

The explanation is: The response of the jet engine thrust to throttle angle movement is not instantaneous and approximates to that of a simple first-order filter with a time constant which is typically in the range 0.3 to 1.5 seconds, depending on the thrust setting and flight condition. Clearly, the lag in the throttle servo actuator response should be small compared with the jet engine response.