(2) Windshields with a P prefix serial number (PPG Industries) are also constructed of five layers: a glass outer layer, a PVB interlayer, a glass structural ply, a PVB interlayer and a glass crew shield. PPG windshields also have a bluish-green tint. The outer glass ply is soda-lime glass.
E. The inner face of the face ply is covered with a conductive coating, which is part of the antifogging and anti-icing systems. Bus bars, embedded in the windshield layers, contact the conductive surface near the top and bottom of the windshield. Two temperature control sensors are laminated into the windshield adjacent to the conductive coating. Only one control sensor is used; one is a spare that is used only if the other fails. Wires from the bus bars and sensors extend through the windshield laminations to the terminals on the inner face.
3. No. 2 and 3 Windows (Fig. 3)
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A. The left No. 2 and 3 windows are the captain's side windows. The right No. 2 and 3 windows are the first officer's side windows. The left and right windows are opposite assemblies and installations.
B. The side windows are designed to be installed from inside the flight deck. They act as a plug and minimizes cabin pressure leakage by compressing the side window pressure seal. When the airplane is pressurized, cabin pressure acting against a side window's surface, forces the side window against the airplane's frame, thus the side window loading acts directly against the airplane structure not through the fasteners.
C. The No. 2 and 3 windows each consist of an inner and an outer pane with a plasticized vinyl interlayer between them. The interlayer allows for thermal differentials and prevents crack propagation between the panes (Fig. 1).
D. The windowpanes are made of tempered glass. Each pane will withstand full cabin pressure should one pane fail.
E. The outboard face of the inner glass ply is covered with a transparent electrically conductive coating for the antifogging system. Bus bars, embedded in the window layers, contact the conductive surface near the forward and aft edges of the windows. The overheat thermostat for the window is held against the inside surface of the window by a spring retainer. A control sensor is retained against the inner pane with a torsion spring. The sensor is replaceable and is provided with pigtails for electrical hook-up.
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