In icing conditions during flight, at which indicated airspeed is wing anti-ice required when icing conditions are present?

• A. Less than 230 KIAS
• B. 230 KIAS or more
• C. Less than 320 KIAS
• D. Any airspeed

Answer: (A)

In icing conditions, wing anti-ice protection is required when your indicated airspeed is below 230 knots because ice tends to accumulate more readily at slower speeds, where the airflow over the wing is less effective at shedding moisture. The anti-ice system, which heats the wing leading edges using bleed air, is activated to prevent ice buildup during these slower, more susceptible flight regimes (like takeoff, climb, and approach). At higher speeds, the rate of ice accumulation is reduced and the system isn’t mandated to stay on purely for safety, so the requirement targets the slower end of the speed range. This rule helps balance safety with performance by ensuring protection exactly where icing risk is greatest.