Icing Evaluation. U-21A Airplane with Low Reflective Paint

An evaluation was conducted of the icing characteristics of a U-21A airplane painted with low reflective paint. Test flights were made in trace, light, and moderate icing conditions. During these tests four shortcomings were noted. The shortcomings were ineffectiveness of the deice boots with rime ice accumulation, inability of the engine air inlet anti-ice system to prevent formation of ice in the engine air inlet, lack of an engine inlet lip boot anti-ice system preflight test, and lack of anti-ice/deice capability for the wing area outboard of the pneumatic boots. From the evaluation it was concluded that the low reflective paint does not significantly affect the ice accumulation characteristics of the U-21A airplane, and also that, regardless of the type paint, in moderate icing conditions at constant power, airspeed will be reduced by 20 to 30 knots.