When Type II or Type IV anti-icing fluids have been applied, wing anti-ice should be ON when?

When Type II or Type IV anti-icing fluids have been applied, wing anti-ice should be ON when?

• A. Immediately after application
• B. Just prior to takeoff thrust if required
• C. Only during flight
• D. Never

Answer: (B)

Type II and Type IV fluids create a protective anti-ice layer on the wings that lasts for a limited holdover time. The wing anti-ice system is used to actively heat the leading edges during the takeoff and initial climb to prevent ice from forming once you’re progressing toward takeoff thrust. Therefore, you turn wing anti-ice on just before applying takeoff thrust if the conditions indicate protection is needed. Activating it immediately after application would waste holdover time or heat the surfaces too early, and turning it on only in flight would leave the wings unprotected during the critical takeoff phase. Never leaving it off when icing conditions exist would risk ice during takeoff.

Type II and Type IV fluids create a protective anti-ice layer on the wings that lasts for a limited holdover time. The wing anti-ice system is used to actively heat the leading edges during the takeoff and initial climb to prevent ice from forming once you’re progressing toward takeoff thrust. Therefore, you turn wing anti-ice on just before applying takeoff thrust if the conditions indicate protection is needed. Activating it immediately after application would waste holdover time or heat the surfaces too early, and turning it on only in flight would leave the wings unprotected during the critical takeoff phase. Never leaving it off when icing conditions exist would risk ice during takeoff.