Abstract: Aircraft attitude along the pitch axis is controlled by inputting a velocity command to a pitch control subsystem that includes a velocity side channel and a gain side channel of a pitch servo amplifier. An output from each channel of the pitch servo amplifier is applied to a pitch servo motor for positioning a primary control surface. The velocity of the pitch servo motor is detected by a velocity detector that generates a velocity feedback signal and control signals for each channel of the pitch servo amplifier. Also responsive to the velocity signal of the detector is a pre-flight test circuit for pre-flight checkout of the pitch control subsystem. In each line from the output of the channels of the pitch servo amplifier is a current detector that is part of a pitch trim control subsystem that responds to the current through the pitch servo motor to generate a trim velocity command signal. This velocity command signal is input to a velocity side channel and a gain side channel of a trim servo amplifier.