Which statement best describes activation of anti-ice and de-ice on ATR?

• A. They are activated automatically regardless of icing
• B. Activated according to icing conditions; they prevent icing on critical surfaces; observe environmental and performance limits.
• C. They are only used on the ground
• D. They do not affect performance limits

Answer: (B)

When icing conditions exist, anti-ice and de-ice are used based on procedures, not automatically. Their purpose is to prevent ice from forming on critical surfaces or to remove ice that has already formed, so the aircraft can maintain lift, control, and engine performance. On ATRs, activation is tied to actual icing conditions and the system is operated within the aircraft’s environmental and performance limits, meaning you use bleed air or electrical power as specified, and you respect limits on when and how the system can be used.

This is why the best description is that they are activated according to icing conditions and designed to prevent icing on critical surfaces, while you must observe environmental and performance limits. The other statements aren’t accurate: icing control is not automatic regardless of conditions, it isn’t limited to ground operations, and the systems do affect performance because they draw power and alter aerodynamics.