Anti-Ice Systems - Cruise Performance Penalties
For aircraft equipped with anti-ice systems which rely on bleed-air offtake from the engines, I'm trying to understand how the associated performance penalties with these systems switched on (I'm thinking about the increased fuel burn for the same speed/altitude) are dealt with during cruise flight planning.
Do aircraft ODM's/Performance Manuals include an optional allowance for anti-ice being on/off?
Or, is this not a flight planning issue because you don't plan to remain cruising in icing conditions?
Regards
WUT