Abstract: To ensure the safety of large aircraft flying through clouds, large airliners should design and install wings, windshields and nacelle anti/deicing systems. First of all, based on the 3 parameters that affect icing intensity: liquid water content(LWC ), ambient temperature and median volume diameter(MVD), and in combination with appendixes C and O of CS25, this paper describes 4 kinds of icing envelops’ characteristics. Secondly, based on the current design level of anti/deicing system, the airworthiness terms of the anti/deicing system are reviewed with 25.1420(a)(1) asthe certification target. Finally, based on the CS25 and AC-25-28, airworthiness compliance analysis is carried out according to the characteristics of the aircraft's various systems, which provides a reference for the design and airworthiness certification of the large passenger aircraft anti/deicing system.

Key words: anti/deicing system, ice detection, airworthiness terms, means of compliance , CS25