Data from the OAT probe on aircraft can be used in several calculation such as flight planning, aircraft take-off performance, cruise performance, density altitude and so forth.

In modern day aircraft, external air temp obtained via the Outside Air Temperature (OAT) probe, for the basic input for air data computers. There are two things to be kept in mind; one, the Static Air Temperature, or SAT, i.e. the temperature of the undisturbed air through which the aircraft will fly and second, the air temperature as the aircraft flies through it. This latter temperature is always a bit higher than the former (dur to kinetic energy is converted to heat at the sensor). ... Read more »