What is LVDT on Boeing 737? (Linear Variable Differential Transducer)

In aviation, safety and performance are paramount. With advancing technology, aircraft manufacturers constantly strive to improve their aircraft systems to ensure efficient operations and enhance safety measures. The Boeing 737, one of the most popular commercial aircraft in the world, incorporates various sensors and transducers to monitor and control critical parameters. One such essential component is the Linear Variable Differential Transducer (LVDT). In this article, we will delve into the details of the LVDT on the Boeing 737 and understand its significance in the aircraft’s functioning.

The Role of Linear Variable Differential Transducer (LVDT)

The Linear Variable Differential Transducer, commonly known as LVDT, is a type of electromechanical sensor used in numerous industries. However, it holds immense importance in the aviation sector, especially on the Boeing 737 aircraft. The LVDT is primarily employed to measure linear displacement or position changes and convert them into electrical signals. It operates based on the principle of electromagnetic induction.

On the Boeing 737, the LVDT plays a crucial role in various systems, including the flight control system, landing gear system, and engine thrust reverser system. Let’s explore its applications in these systems:

Flight Control System

The flight control system of the Boeing 737 relies on the accurate measurement of control surface positions, such as the positions of flaps, ailerons, elevators, and rudder. The LVDTs installed in the flight control system act as position sensors, providing real-time data to the flight control computers. These computers utilize the LVDT signals to determine the required control inputs to achieve the desired maneuverability and stability of the aircraft.

For instance, during takeoff and landing, the position of the flaps needs to be precisely controlled to optimize lift and drag. The LVDTs installed in the flap actuation mechanisms monitor the flap positions and transmit the information to the flight control system. Based on this data, the flight control computers adjust the flaps accordingly to ensure safe and efficient operations. The accuracy and reliability of the LVDTs are crucial in maintaining precise control of these critical flight control surfaces.

Landing Gear System

The landing gear system is another vital component of an aircraft, responsible for safely cushioning the aircraft during landings and takeoffs. The LVDTs used in the landing gear system of the Boeing 737 provide crucial data regarding the position and extension of the landing gear struts. This information is essential for the pilots and the flight control system to ensure the safe extension and retraction of the landing gear.

LVDTs are typically installed in the landing gear actuator mechanisms to measure the linear displacement of the landing gear strut. This data is constantly monitored and relayed to the cockpit, allowing the pilots to have accurate information about the status of the landing gear. Additionally, the flight control system utilizes this information to prevent any potential safety hazards, such as landing gear malfunctions or improper deployment.

Engine Thrust Reverser System

The engine thrust reverser system is a critical feature of an aircraft, enabling it to achieve shorter landing distances and improved braking efficiency. The LVDT plays a vital role in this system by measuring the position and movement of the thrust reverser butterfly doors. These doors redirect the engine’s exhaust flow to generate reverse thrust, aiding in deceleration during landing.

LVDTs are integrated into the thrust reverser actuator mechanisms to precisely measure the linear displacement of the butterfly doors. This positional data is transmitted to the engine control system, allowing it to regulate the thrust reverser operation accurately. The accurate measurement provided by the LVDTs ensures the proper deployment and functionality of the thrust reverser system, thereby enhancing the overall safety and performance of the aircraft.

The Advantages of LVDT on the Boeing 737

The integration of LVDTs in various systems of the Boeing 737 brings several advantages to the aircraft and its operators. Let’s explore some key benefits:

1. Precise Position Measurement: The primary advantage of LVDTs is their ability to provide highly accurate and precise position measurements. This precision is crucial in critical flight control surfaces, landing gear positioning, and thrust reverser deployment. The accurate data from the LVDTs ensures optimal performance and safety in all phases of flight.

2. Electrical Signal Conversion: One of the key benefits of LVDTs is their ability to convert mechanical motion into electrical signals. The LVDTs on the Boeing 737 convert linear displacement or position changes into electrical signals, which can be easily transmitted and processed by the aircraft’s control systems. This allows for efficient and reliable data analysis and control.

3. Robust and Reliable: LVDTs are known for their robustness and reliability. They are designed to withstand harsh environments, including temperature variations, vibrations, and electromagnetic interference. This reliability ensures that the LVDTs onboard the Boeing 737 can continuously provide accurate measurements, even in demanding conditions.


The Linear Variable Differential Transducer (LVDT) plays a significant role in the functioning of the Boeing 737 aircraft. Its applications in critical systems such as the flight control system, landing gear system, and engine thrust reverser system enhance the safety, performance, and efficiency of the aircraft. By accurately measuring linear displacement and converting it into electrical signals, LVDTs provide essential data to the control systems, pilots, and maintenance personnel.

The LVDTs’ precision, reliability, and ability to withstand challenging environments make them indispensable components in the aviation industry. As aircraft technology continues to advance, LVDTs are likely to evolve further, providing even more accurate and efficient measurements for enhanced safety and operational excellence.

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