How do de-icing and anti-icing differ?

• A. De-icing removes ice; anti-icing prevents ice from forming.
• B. Anti-icing removes ice.
• C. De-icing adds de-icing chemical to prevent formation.
• D. Anti-icing is used after de-icing to remove ice.

Answer: (A)

Understanding how icing is managed comes down to what each method does and when it’s used. De-icing is the process of removing ice that has already formed on surfaces, typically by spraying hot fluids or applying heat to melt and shed the ice. Anti-icing, by contrast, is preventive: it’s applied before icing conditions to stop ice from forming or bonding to the surfaces, giving a window of time (holdover time) during which the aircraft should remain ice-free. If ice starts to form after that window, de-icing may be needed again. So, the best description is that de-icing removes ice, while anti-icing prevents ice from forming.