What limitation should be observed when activating anti-ice and de-ice systems on an ATR?

• A. There are no limits
• B. They should be used only on the ground
• C. They must be used within environmental and performance limits
• D. They automatically override all other systems

Answer: (C)

When using anti-ice and de-ice on an ATR, you must operate within the aircraft’s environmental and performance limits. These systems are designed to handle icing only under certain atmospheric conditions and within the power and thermal capacity the airplane can safely provide. Ice can accumulate on surfaces when there is visible moisture in temperatures near or below freezing, and the system’s effectiveness depends on having enough bleed air, electrical power, and cooling capacity available. Running the system outside these limits can lead to inadequate protection, overheating of components, or reduced ability to power other critical systems, potentially affecting flight safety. So you activate and use them only within the certified icing environment and within the system’s performance constraints (power availability, duration, and any speed/altitude restrictions).