How is de-icing performed on the 737?

• A. In flight with heated surfaces
• B. By applying heat to wings only
• C. On the ground by spraying chemicals
• D. By heating the wings in the sun

Answer: (C)

De-icing is done on the ground using glycol-based fluids sprayed onto the aircraft by ground equipment. These fluids melt and coat away ice, frost, or snow on exposed surfaces, so the airplane can taxi and take off safely. The fluids also provide a temporary anti-ice layer to delay re-icing before takeoff. Heating surfaces in flight or relying on the sun isn’t how de-icing is performed; in-flight systems are mainly for anti-icing—keeping surfaces at or above the temperature to prevent ice formation—not removing ice that’s already present on the ground. Spraying fluids on the wings alone wouldn’t treat all critical surfaces, which is why ground de-icing involves comprehensive coverage of the aircraft.