What is the primary purpose of anti-ice systems?

• A. Anti-ice is used to prevent ice formation on critical surfaces; de-ice removes ice.
• B. Anti-ice removes ice that has formed.
• C. Anti-ice systems function only on the engine intakes.
• D. Anti-ice and de-ice are the same thing.

Answer: (A)

Ice on critical surfaces changes their shape and disrupts airflow, so anti-ice systems are designed to prevent that ice from forming in the first place. They keep those surfaces, like leading edges and engine inlets, above freezing by heating them or applying a protective layer. That preventive action preserves lift, handling, and sensor accuracy, reducing the chance of ice-related performance loss or control issues. De-ice systems, by contrast, are used after ice has already formed to remove it. The idea that anti-ice and de-ice are the same isn’t accurate, and limiting anti-ice to engine intakes doesn’t cover the full scope of surfaces protected in flight.