This advisory circular (AC) describes an acceptable means for showing compliance with the requirements of Title 14, Code of Federal Regulations (14 CFR) 25.1419(e), (t), (g), and (h), Ice protection. Part 25 contains the airvworthiness standards applicable to transport category airplanes. This AC provides guidance for: * installing a primary ice detection system, * developing visual cues and installing an advisory ice detection system to alert the flightcrew that the airframe ice protection system (IPS) must be activated, * identifying conditions conducive to airframe icing through the use of temperature and visible moisture cues, and e including in the airplane flight manual (AFM) procedures for activating and deactivating the airframe IPS.