When an aircraft flies through a supercooled droplets cloud, ice accretion occurs on the front parts of structure, (i.e. wing, tail plane, air intake), what can conduct to fatal accidents. In order to avoid icing, de-icing or anti-icing protection system are supplied by the pilot when he encounters icing conditions.

New generation of airplanes will be more sensitive to icing because airfoils will be thinner and engines will be less powerful. Consequently, improvement of protection systems are necessary. Based on icing wind tunnel test, numerical codes which can predict ice accretion are developed.