Some transport aircraft concepts currently being studied are extremely lightweight and flexible compared to traditional designs. The feasibility of the new concepts may depend on flight control systems to alleviate the structural loads. Development of this type of advanced system requires an analysis technique that is efficient enough to enable rapid batch simulation without sacrificing the accuracy necessary for control law design. 

Ref. 1 describes a state space formulation that eliminates the need for lag terms to represent the unsteady aerodynamics. Comparisons with more elaborate solution techniques have shown excellent correlation for structural response data such as accelerations, rates and displacements due to control surface excitation. We will further develop this analysis technique by deriving output equations for the structural loads due to various inputs. The following section provides a brief summary of the basic state space formulation.