On the design of command and stability augmentation systems for advanced technology aeroplanes

There exists an enormous wealth of published material describing the application of so called, 'modern control methods' to the design of fliglat control systems for piloted aeroplanes. It is also evident, with the exception of a very small number of recent applications, that there is a conspicuous lack of enthusiasm on the part of the airframe manufacturers to adopt this design technology, especially for the design of command and stability augmentation systems for piloted aeroplanes. It is possible to speculate on the reasons for this apparent lack of interest, but to do so might well result in a misplaced condemnation of modern control methods. Since evidence exists to suggest that some modern control system design strategies have overlooked important flight dynamics considerations, the discussion is turned around here by drawing attention to some of the more important considerations in command and stability augmentation system design. The object is, therefore, to inform the designer, of whatever persuasion, of the critically important aspects of command and stability augmentation system design for the advanced technology aeroplane.