How is ice prevented from forming on the nose cowl, nose dome, and inlet guide vanes of a turbine engine?

How is ice prevented from forming on the nose cowl, nose dome, and inlet guide vanes of a turbine engine?

• A. Cold air from the inlet is redirected to melt ice
• B. Ice forms and is allowed; no prevention
• C. Hot compressor bleed air flows through passages in these components to elevate surface temperatures sufficiently to prevent ice from forming
• D. Apply water spray to wash away ice

Answer: (C)

Ice is prevented by heating the leading-edge surfaces with hot compressor bleed air. The anti-ice system takes hot air from the engine’s compressor and routes it through internal passages in the nose cowl, nose dome, and inlet guide vanes, raising their temperatures enough to keep them above freezing so ice cannot form (or is quickly melted). A control valve and temperature/flow regulation maintain the right amount of heat without overheating the components. This method is preferred because it uses engine-supplied heat to protect critical intake surfaces in icing conditions. Redirecting cold air would worsen icing, and letting ice form is unsafe. Water spray isn’t a reliable or primary method for preventing ice on these surfaces.

Ice is prevented by heating the leading-edge surfaces with hot compressor bleed air. The anti-ice system takes hot air from the engine’s compressor and routes it through internal passages in the nose cowl, nose dome, and inlet guide vanes, raising their temperatures enough to keep them above freezing so ice cannot form (or is quickly melted). A control valve and temperature/flow regulation maintain the right amount of heat without overheating the components.

This method is preferred because it uses engine-supplied heat to protect critical intake surfaces in icing conditions. Redirecting cold air would worsen icing, and letting ice form is unsafe. Water spray isn’t a reliable or primary method for preventing ice on these surfaces.