How is engine anti-ice typically supplied on a narrowbody?

• A. By bleed air or electric heating to nacelle and engine anti-ice components.
• B. By hydraulic oil heating of the engine casing.
• C. By cooling the engine with external air.
• D. By applying fuel-rich oxygen to the nacelle.

Answer: (A)

Engine anti-ice on a narrowbody is about delivering heat to the surfaces most exposed to icing—the nacelle leading edge and the engine inlet. The usual method is hot bleed air from the engine’s compressor (or from another source in the aircraft) routed through anti-ice ducts to those surfaces, so the airfoil and lip stay above freezing. Electric heating elements can also provide heat where bleed air isn’t ideal or as a supplement. This approach directly prevents ice from forming and building up where it would disrupt airflow into the engine. Hydraulic oil heating isn’t used for anti-ice, cooling the engine with external air would promote icing, and applying fuel-rich oxygen to the nacelle isn’t a real anti-ice method.