Aircraft autopilot system

Claim 1

In an aircraft autopilot system having a pictorial navigation indicator selectively adjustable to different headings and providing an electric signal representative thereof; an artificial horizon indicator providing a signal corresponding to unbalanced altitude of the aircraft; a radio coupler selectively adjustable to provide a controlling signal to follow a course defined by an omni, ILS beams (LOC NORM), preset heading of a pictorial navigation indicator or to seek out a predetermined omni (NAV); an amplifier having inputs for receiving the recited electric signals and outputs interconnected with a pitch servosystem and a roll servosystem for adjusting the controls of the aircraft; and altitude hold means selectively adjustable to provide signals corresponding to different altitudes which are fed into the amplifier for automatically positioning the aircraft to the selected altitude; and a glide slope coupler including a glide slope adapter interconnected with the artificial horizon indicator and altitude hold for cooperative action with the radio coupler to track the aircraft along ILS beams for landing; and a console including first switches for selectively connecting and disconnecting the amplifier with individually adjustable roll and pitch signal means, and second switches for selectively connecting and disconnecting the altitude hold and heading from the pictorial navigation indicator and radio coupler, the improvement comprising: first means selectively actuatable to connect the glide slope adapter to electrical power during the existence of a glide deflection signal, said glide slope adapter being disconnected from electric power when either (a) the altitude hold is inoperative, or (b) the altitude hold is operative and at least one of the following exists: the radio switch LOC NORM is off, or glide slope coupling has been achieved; second means for maintaining the autopilot under control of the preset heading on the pictorial navigation indicator when the radio coupler is preset to NAV including third means for placing the automatic pilot under control of the radio coupler and interrupting heading control by the pictorial navigation indicator upon actual intercept of a selected omni occurring; and selectively actuatable fourth means for disconnecting the console pitch signal from the amplifier and interconnecting a pitch signal of predetermined fixed magnitude to said amplifier, and further means simultaneously actuated for energizing a GO-AROUND light.