Modeling and Simulation of Failures for Primary Control Surfaces

This paper describes the results of the extension of an existing failure modeling approach for the longitudinal aircraft dynamics to the lateraldirectional dynamics. In particular, a general formulation is developed for the most common failure scenarios, that is actuator blockage with and without a missing portion of the control surface. The approach consists of modeling the contribution of each individual control device within the expressions for the total external forces and moments using a single “efficiency” parameter that is easily accessible during simulation. Although the methodology can be applied to any force and moment generating control surface the paper describes simulation results relative to failures for elevators/stabilators, ailerons, and rudder occurring separately and simultaneously.