Design and Research on the Refit Scheme for Natural Icing Flight Test of Large Civil Aircraft

The natural icing flight test is an important compliance method for flight in icing conditions defined in CCAR25-R4 Appendix C. It is characterised by high risk, high difficulty, high cost and requires a large number of specialized refits. This article analyses the main refit requirements based on the natural icing flight test verification tasks of large civil aircraft, including cloud combination probe, cameras, painting, ice scales, etc. The refit scheme design includes: using the FENSAP-ICE icing calculation software, designing the installation position and height of the cloud combination probe; The quantity, location, and functional design of cameras; The scope, colour matching, and scale design of painting; The quantity, layout, priority definition, scale, angle, colour matching design of ice scales. The refit scheme designed in this article can provide reference for the natural icing test flight refit of large civil aircraft.