What is TAT on Boeing 737? (Total Air Temperature)

The Total Air Temperature (TAT) is an important parameter in aviation, particularly on the Boeing 737 aircraft. It refers to the temperature of the air that the aircraft is flying through, and it plays a crucial role in various aspects of aircraft operation. In this article, we will delve into the significance of Total Air Temperature on the Boeing 737 and explore its impact on different systems and components of the aircraft.

Importance of Total Air Temperature

Total Air Temperature is used in several critical calculations and systems on the Boeing 737. One of its primary applications is in the calculation of airspeed. The TAT, along with the static air temperature and the aircraft’s true airspeed, is used to calculate the calibrated airspeed (CAS). The CAS provides a more accurate representation of the aircraft’s true airspeed, compensating for factors such as changes in temperature and altitude.

Furthermore, Total Air Temperature is crucial for the operation of the aircraft’s anti-ice systems. The TAT is used to determine the presence of ice crystals in the air and activate the appropriate ice protection systems, ensuring the aircraft remains ice-free during flight. The accurate measurement of TAT is essential to prevent the formation of ice on critical surfaces, which could negatively impact the aerodynamics and performance of the aircraft.

In addition to airspeed calculation and anti-ice systems, Total Air Temperature is vital for the proper functioning of the aircraft’s engine control system. The TAT is used by the engine control unit to adjust the engine’s fuel flow, ensuring optimal performance in varying temperature conditions. It helps maintain the engine within its operational limits and prevents the risk of overheating or performance degradation.

Furthermore, Total Air Temperature is an essential input for the aircraft’s air conditioning system. The TAT is used to regulate the temperature of the air supplied to the cabin, ensuring passenger comfort throughout the flight. By accurately measuring the TAT and adjusting the air conditioning system accordingly, the Boeing 737 can provide a pleasant cabin environment even in extreme temperature conditions.

Overall, Total Air Temperature plays a critical role in the operation, performance, and safety of the Boeing 737 aircraft. Its accurate measurement and utilization in various systems and calculations contribute to the aircraft’s efficiency, reliability, and passenger comfort.

Measuring Total Air Temperature

There are specific instruments and sensors on the Boeing 737 dedicated to measuring Total Air Temperature. One of the primary components is the Total Air Temperature Probe. This probe is typically located outside the aircraft’s fuselage, ahead of the engine intake, where it can accurately measure the temperature of the air during flight.

The Total Air Temperature Probe consists of a small tube that faces into the airflow. This design allows it to capture the undisturbed air temperature and minimize any influence from the aircraft’s heat or other components. The probe is designed to be highly sensitive and responsive to changes in air temperature, providing accurate readings to the aircraft’s systems.

Once the TAT is measured by the Total Air Temperature Probe, it is transmitted to the aircraft’s avionics systems for further processing and utilization. The TAT information is typically displayed on the cockpit instruments, allowing pilots to monitor the temperature in real-time. It is also input into various calculations and systems, as mentioned earlier, to ensure optimal aircraft performance.


The Total Air Temperature (TAT) is a crucial parameter on the Boeing 737 aircraft. It is used in various calculations, systems, and components to ensure the aircraft operates efficiently and safely. From airspeed calculation to anti-ice systems, engine control, and cabin air conditioning, the TAT has a significant impact on different aspects of the aircraft’s operation. Its accurate measurement and utilization contribute to the overall performance, reliability, and passenger comfort of the Boeing 737.

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