Abstract: An automatic pilot apparatus, for controlling an aircraft during the execution of a maneuver to capture a predetermined altitude, utilizes an altitude control law formula and signal which define a circular flight path intercepting the predetermined altitude and which result in a normal acceleration force on the aircraft. A signal representative of the normal acceleration force is utilized to generate a predictive pitch command signal which is combined with the control law signal to generate a pitch attitude command signal, thereby allowing the aircraft to smoothly capture the predetermined altitude.

Abstract: An optical pulse-forming switch includes a pair of spaced apart photodetectors and a rotatable shutter arranged to permit sequentially illuminating first one photodetector and then the other, depending on the sense of rotation, to produce out-of-phase pulse trains. The optical pulse-forming switch is interfaced with a pair of synchronized flip-flops and a phase detection counter control circuit which senses rotation extent and direction. The counter control circuit drives a counter that stores the number of passed angular increments and stores direction of rotation, the counter being interrogated and reset at regular time intervals. Thus, the input shaft rotation is converted into a digital quantity by maintaining a running summation of counter values. The operator reference indicator is accordingly brought up to date following each input conversion.