Cockpit windows on modern transport aircraft are complex multi-layer structures designed to withstand pressurisation loads, thermal stresses, bird strikes, and other mechanical hazards. The forward-facing windshields are typically constructed from multiple plies of glass and plastic with an electrically conductive heating element embedded between layers

Statement 1: Cockpit windows never have an additional speed restriction related to bird impact when window heating is inoperative → INCORRECT. Window heating on modern transport aircraft serves a dual function: it prevents icing on the outer surface AND it raises the temperature of the glass structure, which significantly increases its toughness and resistance to high-energy bird strikes. When window heat is lost, the cold glass is more brittle and more vulnerable to damage from bird impact. Most aircraft MEL limitations or QRH procedures for inoperative window heat include a speed restriction, typically expressed as a maximum IAS, to reduce the bird strike energy the window must withstand. 

Statement 2: Cockpit side windows are always provided with a de-icing system → INCORRECT. Forward windshields on large transport aircraft are universally equipped with electrical heating for anti-icing and structural purposes. However cockpit side windows (the smaller panels to the left and right of the main windshields, sometimes used as direct vision emergency exits) are not always provided with active de-icing or anti-icing heating. The provision of side window heating depends on the aircraft type, the operator specification, and the specific certification requirements for that aircraft. Using the absolute term always makes this statement incorrect because there are certified aircraft types and configurations where cockpit side windows are not heated.