Prediction of Icing Effects on the Coupled Dynamic Response of Light Airplanes

Abstract

Most methods for the preliminary safety and performance evaluation of airplane dynamical response, stability characteristics, and climb performance in icing conditions require relatively sophisticated methods, based on detailed empirical data and existing flight data. This paper extends a pitch axis 3-degree-of-freedom methodology to the fully coupled, 6-degree-of-freedom case. It evaluates various levels of icing severity and addresses distributed icing with unequal ice distribution between wing halves on the coupled pitch, roll, and yaw responses. The important aspect of dynamic response sensitivity to pilot control input with the autopilot disabled is also highlighted. Using only basic mass properties, configuration, propulsion data, and known icing data from a similar configuration, icing effects are applied to the 6-degree-of-freedom dynamics of a nonreal-time simulation model of a different, but similar, light airplane. Results presented in the paper for a series of simulated climb maneuvers and cruise disturbances with equal or unequal ice levels between wing halves show that the methodology captures the basic effects of ice accretion on the coupled pitch, roll, and yaw responses and the sensitivity of the dynamic response to pilot control inputs.