Turbine engines, and particularly gas or combustion turbine engines, are rotary engines that extract energy from a flow of combusted gases passing through the engine onto a multitude of rotating turbine blades.  Gas turbine engines have been used for land and nautical locomotion and power generation, but are most commonly used for aeronautical applications such as airplanes or helicopters.  In airplanes, gas turbine engines are used for propulsion of the aircraft. 
During operation of a turbine engine, the air temperature (can be measured by a specially designed total air (TAT) temperature probe mounted on the surface of the aircraft or the interior walls of the turbine engine.  The TAT probe is designed to reduce the velocity of the air to rest relative to the aircraft, thus consistently sensing air temperature between total and static temperature.  TAT is an important input for calculating static air temperature and true airspeed. 
Because TAT sensors are often mounted in front of the turbine engine or in front of the compressor, they can be exposed to adverse conditions including high Mach numbers and icing conditions, as well as water and debris.  The primary function of the TAT sensor is to sense the air temperature and filter out water, debris and any ice that may reach the sensor.