Total Temperature Measuring Instruments (Turbine powered Subsonic Aircraft)
AS793A
This standard covers three basic types of total-temperature-measuring instruments used as a means of determining the total temperature developed by adiabatic heating of the air due to motion of the aircraft through the air.
Type I - Flush-type total-temperature sensor
Type II - Probe-type total-temperature sensor (electrically heated)
Type III - probe-type total-temperature sensor (unheated)