Can the APU provide bleed air for anti-icing?

Can the APU provide bleed air for anti-icing?

• A. Yes
• B. No
• C. Sometimes
• D. Only during takeoff

Answer: (B)

Anti-icing needs a source of hot air to keep surfaces free of ice, and that hot air is delivered through the bleed-air system. On most jets, the anti-ice system draws bleed air from the engines (or uses electric heating where designed) to warm the wing and nacelle leading edges and other critical surfaces. The APU’s bleed air is used primarily for the environmental control system and for engine starting on the ground or when engine bleed is unavailable, not for wing or nacelle anti-icing. Because the APU bleed is not routed to the anti-ice system and may not provide the required continuous, high-flow heat, it cannot power anti-icing. So, anti-icing is not supplied by the APU bleed air.

Anti-icing needs a source of hot air to keep surfaces free of ice, and that hot air is delivered through the bleed-air system. On most jets, the anti-ice system draws bleed air from the engines (or uses electric heating where designed) to warm the wing and nacelle leading edges and other critical surfaces. The APU’s bleed air is used primarily for the environmental control system and for engine starting on the ground or when engine bleed is unavailable, not for wing or nacelle anti-icing. Because the APU bleed is not routed to the anti-ice system and may not provide the required continuous, high-flow heat, it cannot power anti-icing. So, anti-icing is not supplied by the APU bleed air.