What temperature must the SAT be for the cowl anti-ice system to be unnecessary in icing conditions?

The correct response indicates that the cowl anti-ice system is unnecessary in icing conditions when the Static Air Temperature (SAT) is at or below -40 degrees Fahrenheit (-40 degrees Celsius). This is because at temperatures of -40F/-40C and below, the conditions are such that the air is typically cold enough that the formation of ice is minimized, reducing the need for anti-ice systems that would otherwise be necessary at warmer temperatures where ice could accumulate.

In practical terms, once the ambient air reaches this extreme cold, the risks associated with ice formation on engine cowlings decrease significantly, and as such, operating the anti-ice system is not required. This information is crucial for pilots to understand as it influences both safety and fuel efficiency considerations during flight operations in potentially icing conditions.

The other temperature options do not correctly reflect the threshold at which icing conditions become less concerning from an anti-ice operation perspective.