Longitudinal Handling Quality Analysis of a Civil Transport Aircraft Encountering Turbulence

The objective of this study is to analyze an aircraft's longitudinal aerodynamic characteristics and flight handling quality in the short-period mode by using flight data recorder data from a civil transport aircraft encountering turbulence. The extended Kalman filter is used to enhance the quality of the recorded data through a kinematics compatibility check and, simultaneously, estimate some unrecorded parameters. In addition, the turbofan engine's thrust is estimated with a newly established thrust model using the flight data recorder data, whereas the coefficients of aerodynamic forces and moments are evaluated with the aircraft's dynamics equations. The aircraft's longitudinal aerodynamic derivatives are then estimated by a neural network method based on radial-based functions. The results for this flight show that the short-period dynamic characteristic ofthe aircraft is stable, but that the flight handling quality degrades to Level 3.