Airplane: Outside Air Temperature (OAT) Gauge

The outside air temperature (OAT) gauge is a simple and effective device mounted so that the sensing element is exposed to the outside air. The sensing element consists of a bimetallic-type thermometer in which two dissimilar materials are welded together in a single strip and twisted into a helix. One end is anchored into protective tube and the other end is affixed to the pointer, which reads against the calibration on a circular face. OAT gauges are calibrated in degrees °C, °F, or both. An accurate air temperature provides the pilot with useful information about temperature lapse rate with altitude change. 

Flight instruments allow an aircraft to be operated with maximum performance and safety, especially when flying long distances. Manufacturers provide the necessary flight instruments, but to use them effectively, pilots must understand how they work. 

As a pilot, it is important to become familiar with the operational aspects of the pitostatic system and associated instruments, the vacuum system and associated instruments, the gyroscopic instruments, and the magnetic compass.