How should wings and horizontal surfaces be sprayed?

Spraying the wings and horizontal surfaces from the tip toward the root and from the leading edge to the trailing edge ensures thorough coverage and effective de-icing. This method allows for better management of fluid flow, as the fluid can move from areas of higher concentration to lower concentration, which is particularly important in preventing ice buildup.

By starting at the tip, the de-icing fluid can follow the natural lines of airflow and gravity. Applying from the leading edge to the trailing edge, when combined with the tip-to-root technique, helps in removing ice and snow by ensuring that the fluid can run over the entire surface without leaving any spots untreated. This comprehensive method maximizes efficiency and guarantees that critical areas receive the necessary treatment to maintain aircraft performance and safety.

Other methods, like spraying solely from the leading edge to the trailing edge or in a circular motion, could lead to uneven application and potential accumulation of ice, leaving some areas unprotected. The focused approach of spraying in two directions ensures that all surfaces are adequately addressed.