Investigation of Manual Control Behaviour During Flight Control Mode Switching: Test Procedure and Preliminary Results
This paper describes pilot-in-the-loop experiments that are used to investigate peculiarities in manual control behaviour in case of flight control law reconfiguration. In such situations a closed-loop pilot-vehicle system (PVS) instability can occur that manifests itself in the form of an unwanted oscillatory aircraft reaction called ``pilot-involved oscillation'' (PIO). A focus of the experiments was to provide an answer to the question, whether PIOs can occur following sudden flight control mode switching, even if the aircraft dynamics before and after switching are not rated PIO-prone. The determination of linearised aircraft dynamics from a nonlinear aircraft model is described and a handling qualities database is presented. Linearised aircraft have been determined for the aircraft with augmentation by flight control laws and with direct link between pilot inceptor and control surface. An explanation of the test station, the flying task and the conduct of the experiments is given. Preliminary results are shown and conclusions regarding the experimental approach are drawn.