This section presents the basic equations for computing ice protection requirements for nontransparent and transparent surfaces and for fog and frost protection of windshields. Simplified graphical presentations suitable for preliminary design and a description of various types of ice, fog, frost, and rain protection systems are also presented.
There have been significant increases in icing technology since this material was originally written in 1969 as part of the second edition of ARP1168. The original version of AIR1168/4 only contained errata from ARP1168. No updates were made as part of that revision. With the significant advancements in icing technology since 1969, a revision to this document was required to make it compatible with current technology.