Device for adjusting gas turbine engine fuel control system in accordance with engine parameter

A fuel control system for a gas turbine engine of the kind including a hydromechanical speed governor fuel control in which a fuel valve is movable under the influence of a control input element, operable for example by the pilot of an aircraft in which the engine is installed, and speed sensing means, the effect of said control input element on said fuel valve being variable through the intermediary of an electromechanical trim device controlled by an electronic control circuit sensitive to at least one engine parameter, wherein said electronic control circuit includes error signal generating means for producing an error signal representing the difference between the desired and actual values of said engine parameter, a proportional-plus-integral controller circuit for producing the output signal which is applied to said electromechanical trim device, means for generating a trim datum signal dependent on the control input and means for setting the integrator included in the proportional-plus-integral control circuit to a value corresponding to the difference between the trim datum signal and the output of the proportional part of the proportional-plus-integral control circuit when the magnitude of a function of the error signal exceeds a predetermined value.