melt the ice 950 in one embodiment the thickness of the inlet cowling is on the order of 0 1 u2033 0 2 u2033 the structural skin 904 is formed of a metallic or composite material having a thickness between about 0 02 u2033 and 0 10 u2033 the first insulation layer 906 is formed of an electrically inert i e electrically insulative material having a thickness between about 0 01 u2033 and 0 04 u2033 the heater layer 908 comprises electrical heaters formed of a metallic or conductive material on a nonconductive plastic film or other substrate and having a thickness between about 0 005 u2033 and 0 020 u2033 the second insulation layer 910 is formed of an electrically inert i e electrically insulative but thermally conductive material having a thickness between about 0 01 u2033 and 0 04 u2033 and the erosion shield 912 comprises a thermally conductive metallic skin or coating having a thickness between about 0 002 u2033 and 0 020 u2033 instead of being mounted on the inner surface of the inlet cowling 40 as shown in fig4 6 the ice protection electrical heaters 908 may be mounted on the outer surface when positioned on the outer surface the ice protection electrical heaters are more directly exposed to the ice and so the energy efficiency of the system may improve through holes may be formed in some of the underlying layers of the cowling 40 at spaced apart intervals to accommodate wires and other connections to deliver current to the ice protection electrical heaters fig9 b shows a cross section of an inlet cowling 40 b in which the heater forms the outer surface of the cowling.