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The effect of ice accretion on aircraft performance and control during trim conditions was modeled and analyzed. A six degree-of-freedom computational flight dynamics model was used to study the effect of ice accretion on the aircraft dynamics. The effects of turbulence and sensor noise were modeled and filters were developed to remove unwanted noisy data without affecting the short period and phugoid modes. This study is part of a larger research program to develop smart icing system technology. The goal of the study reported here was to develop techniques to sense the effect and location of ice accretion on aircraft performance and control during trimmed flight. Control surface steady and unsteady hinge-moments were modeled as a potential aerodynamic performance sensor. Microburst and gravity wave atmospheric disturbances were modeled and their effects on the aircraft performance and control were compared to that of an icing encounter. The simulations showed that atmospheric disturbances could be differentiated from icing encounters. The hinge-moment sensors proved very useful in identifying the wing versus tail location of aircraft icing.

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Research is reported on aircraft performance and control in icing, related to the development of Smart Icing Systems for improved flight safety. Microburst and gravity wave atmospheric disturbances were modeled, and their effects on the aircraft performance and control were compared to that of an icing encounter. Simulations were run using a six degreeof-freedom computational flight dynamics model. The study showed that microbursts could easily be differentiated from icing encounters. On the other hand gravity waves are more difficult to differentiate. A plan was formulated for developing an envelope protection system effective in icing conditions. Two dimensional airfoil data were analyzed and showed promising results for prediction of envelope limit exceedence. Changes in unsteady hinge moments were especially effective in predicting stall.

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