Forum: F-16 Procedures

What, if anything, is lost with the Engine Anti-Ice switch in the ON position (Pratt or GE) rather than the Auto position? Any quantifiable performance loss or reduction in engine life?

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With ANTI-ICE on, the engines 'bleed' hot air from the compressor into the front struts (stators) and nose cone of the engine to keep them from icing. The inlet strut is also electrically heated, but this has no effect on the engine or performance.

When air is 'bled' from the compressor, RPM and operating temperature typically will increase slightly to compensate for the loss of pressure, and thrust will be reduced somewhat as the engine adjusts to the reduction in flow/pressure available for combustion.

The big thing affected is stall margin; by adding high temperature air into the engine inlet, the air density is reduced. If ANTI-ICE malfunctions open (ON) at higher power or altitudes, compressor stalls can (and most likely will) result. Engine damage can be done by the abnormally high inlet temperatures if ANTI-ICE is stuck on at high power. The F100's control system normally prevents ANTI-ICE function at high power or altitude, providing safe operation.

As with most automated systems. It is best to allow the engine's control system and the anti-ice system to decide when and how to activate. ANTI-ICE - AUTO works for most of the situations encountered. The only time I could think where you'd want to use ANTI-ICE - ON is if you believed your ice detector in the inlet has failed for some reason.

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TEG

Forum: F-16 Procedures

Engine Anti-Ice Off?