What is SAT on Boeing 737? (Static Air Temperature)

The Static Air Temperature (SAT) is an important parameter that pilots and aircraft engineers need to consider during flight operations. SAT refers to the temperature of the air that surrounds the aircraft while it is in motion. It plays a crucial role in various aspects of aviation, including aircraft performance, flight planning, and engine efficiency.

On a Boeing 737 aircraft, the SAT is measured using various instruments and sensors located in different parts of the aircraft. This temperature reading helps pilots accurately calculate aircraft performance parameters such as true airspeed, indicated airspeed, and Mach number. It is also essential for calculating fuel consumption and engine thrust.

In this article, we will explore the significance of Static Air Temperature and its impact on the operation of a Boeing 737 aircraft.

How is Static Air Temperature Measured on a Boeing 737?

The measurement of Static Air Temperature on a Boeing 737 involves the use of specialized instruments known as Total Air Temperature (TAT) sensors. These sensors are typically located in the aircraft’s pitot-static system and are designed to provide accurate temperature readings.

The pitot-static system is a crucial component of an aircraft, consisting of the pitot tube and the static port. The pitot tube measures the total air pressure, which includes both the impact pressure (ram air pressure) and the static pressure. The static port, on the other hand, measures the static pressure of the surrounding air.

The TAT sensors, which are part of the pitot-static system, measure the impact pressure and then compensate for the effects of airspeed on the temperature reading. This compensation allows the TAT sensors to provide an accurate static air temperature reading regardless of the aircraft’s speed and altitude.

The data from the TAT sensors is then transmitted to the aircraft’s Flight Management System (FMS), which calculates various performance parameters based on the received temperature readings. These calculations are crucial for the safe and efficient operation of the Boeing 737 aircraft.

The Importance of Static Air Temperature in Aircraft Performance

The Static Air Temperature significantly affects the performance of a Boeing 737 aircraft in several ways:

1. True Airspeed Calculation: The SAT is used to calculate the True Airspeed (TAS), which represents the actual speed of the aircraft through the air. TAS is necessary for determining the aircraft’s performance limitations, including stall speed, maneuvering speed, and maximum speed.

2. Indicated Airspeed Calculation: The SAT also plays a crucial role in calculating Indicated Airspeed (IAS), which is the airspeed displayed on the aircraft’s airspeed indicator. Indicated Airspeed is important for maintaining safe operating speeds during takeoff, climb, descent, and landing.

3. Mach Number Calculation: The Mach number represents the ratio of the aircraft’s true airspeed to the speed of sound. It is a critical parameter for determining the aircraft’s aerodynamic performance and is calculated using the SAT and the speed of sound at a given altitude.

Considering the importance of the Static Air Temperature in aircraft performance calculations, accurate temperature readings are crucial. Even a slight error in the SAT measurement can significantly impact the aircraft’s performance, resulting in potential safety risks.


The Static Air Temperature (SAT) is a vital parameter in the flight operations of a Boeing 737 aircraft. It is measured using specialized sensors within the aircraft’s pitot-static system, which compensate for the effects of airspeed on the temperature reading. The SAT is crucial for calculating true airspeed, indicated airspeed, and Mach number, which are essential for determining aircraft performance limits and maintaining safe operating speeds.

Accurate and reliable SAT measurements are crucial for the safe and efficient operation of the Boeing 737 aircraft. Pilots and aircraft engineers must understand the significance of SAT and ensure that the temperature readings are correct to avoid potential performance issues and safety risks.

For More: What is ADIRS on Boeing 737? (Air Data Inertial Reference System)