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)

Purpose:

This standard establishes essential minimum safe performance requirements for total temperature measuring instruments, primarily for use with turbine-powered subsonic transport aircraft, the operation of which may subject the instruments to the environmental conditions specified in paragraph 3.4 et seq.