Probe Housing Electrical connector Strut Right ice detector Left ice detector Figure 15-4.  An ice detector alerts the flight crew of icing conditions and, on some aircraft, automatically activates ice protection systems.  One or more detectors are located on the forward fuselage. Thermal Pneumatic Anti-icing Wing and Horizontal and Vertical  Stabilizer Anti-Icing Systems Wing Anti-Ice (WAI) System Deicing equipment is designed to remove ice after it begins  to accumulate typically on the wings and stabilizer leading  edges. Ice may be controlled on aircraft structure by the  methods described in  Figure 15-5. Thermal systems used for the purpose of preventing the  formation of ice or for deicing airfoil leading edges usually  use heated air ducted spanwise along the inside of the leading  edge of the airfoil and distributed around its inner surface.  These thermal pneumatic anti-icing systems are used for  wings, leading edge slats, horizontal and vertical stabilizers,  engine inlets, and more. There are several sources of heated  air, including hot air bled from the turbine compressor,  engine exhaust heat exchangers, and ram air heated by a  combustion heater.  The wing leading edges, or leading-edge slats, and horizontal  and vertical stabilizer leading edges of many aircraft make  and models have anti-icing systems installed to prevent the  formation of ice on these components. The most common  anti-icing systems used are thermal pneumatic, thermal  electric, and chemical. Most general aviation (GA) aircraft  equipped to fly in icing conditions use pneumatic deicing  boots or a chemical anti-ice system. High-performance  aircraft may have “weeping wings.” Large transport-category  aircraft are equipped with advanced thermal pneumatic  or thermal electric anti-icing systems that are controlled  automatically to prevent the formation of ice. Thermal wing anti-ice (WAI or TAI) systems for business  jet and large-transport category aircraft typically use hot air   bled from the engine compressor.  [Figure 15-6]  Relatively  large amounts of very hot air can be bled off the compressor,  providing a satisfactory source of anti-icing heat. The hot  air is routed through ducting, manifolds, and valves to  components that need to be anti-iced.  Figure 15-7  shows a  typical WAI system schematic for a business jet. The bleed  air is routed to each wing leading edge by an ejector in each  Leading edge of the wing Leading edges of vertical and horizontal stabilizers  Windshield, windows Heater and engine air inlets Pitot and static air data sensors Propeller blade leading edge and spinner Carburetor(s)  Lavatory drains and portable water lines Thermal pneumatic, thermal electric, chemical, and pneumatic (deice) Thermal pneumatic, thermal electric, and pneumatic (deice) Thermal pneumatic, thermal electric, and chemical Thermal pneumatic and thermal electric Thermal electric Thermal electric and chemical Thermal pneumatic and chemical Thermal electric Location of ice Method of control Figure 15-5.  Typical ice control methods. 15-4