What is LK on Airbus A320? (Lock)

The Airbus A320 is a popular aircraft model that has revolutionized the aviation industry with its advanced technology and efficient design. As pilots and aviation enthusiasts delve into the technicalities of this amazing aircraft, one term that often arises is “Lock.” So, what is Lock on Airbus A320? In this article, we will explore the concept of Lock, its significance, and how it contributes to the overall performance and safety of the Airbus A320.

The Role of Lock on Airbus A320

Lock on the Airbus A320 refers to a system called the Lock Control Unit (LCU), which is responsible for managing and controlling various essential functions of the aircraft. The LCU acts as a central hub, connecting and coordinating multiple systems such as the flight control computers, autopilot, and autothrust system, ensuring seamless communication and operation between these critical components.

The Lock system plays a vital role in maintaining the accuracy and reliability of flight control inputs, ensuring the aircraft responds precisely to pilot commands. By integrating functions and providing centralized control, the Lock system enhances the overall efficiency and safety of the Airbus A320 during flight operations.

The Components of Lock

The Lock system on the Airbus A320 consists of several components working in tandem to deliver optimal performance. Let’s take a closer look at some of these key components:

1. Flight Control Computers (FCC)

At the core of the Lock system are the Flight Control Computers (FCC). The A320 is equipped with two FCCs, known as FCC1 and FCC2, which are redundant and capable of independently controlling the aircraft. These computers continuously receive and analyze data from various sensors, such as airspeed indicators, angle of attack sensors, and accelerometers, to determine the aircraft’s attitude, speed, and position.

The FCCs process this information and generate control signals that are transmitted to the actuators, such as servo valves, which then move the flight control surfaces accordingly. This closed-loop system enables precise control of the aircraft’s flight parameters, contributing to its exceptional maneuverability and stability.

2. Autopilot

The Lock system also incorporates an advanced Autopilot function, allowing the Airbus A320 to fly automatically along a predefined flight path. The Autopilot receives input from the FCCs and autonomously adjusts the flight control surfaces to maintain the desired trajectory, based on the selected mode and parameters.

With the Autopilot engaged, the aircraft can maintain headings, altitudes, and speeds with high accuracy, relieving the pilot of some manual control and reducing workload during long flights. The Lock system ensures smooth integration between the Autopilot and other flight systems, enabling seamless transitions between manual and automatic modes.

3. Autothrust

The Autothrust system, another integral component of the Lock system, provides automatic control of engine thrust, optimizing performance and fuel efficiency. The Autothrust receives input from various aircraft systems, including the FCCs and the Flight Management System (FMS), to determine the desired thrust levels based on pilot inputs and flight parameters.

By continually adjusting the engine thrust, the Autothrust system maintains the selected speed, whether it be the aircraft’s maneuvering speed during takeoff and landing or the desired cruise speed during flight. The Lock system ensures accurate synchronization between the Autothrust system and other flight control functions for a seamless and efficient operation.

The Advantages of Lock on Airbus A320

The incorporation of Lock systems on the Airbus A320 provides numerous advantages for both pilots and passengers. Let’s explore some of the key benefits:

1. Enhanced Safety

The Lock system enhances the safety of the Airbus A320 by ensuring accurate and precise control of the aircraft. The centralized control provided by the Lock system minimizes the risk of conflicting inputs from various flight control components, reducing the possibility of errors or inconsistencies in the aircraft’s response to pilot commands.

Additionally, the redundant nature of the Lock system, with multiple FCCs and backup systems, ensures a high level of reliability and redundancy. In the event of a failure or malfunction in one component, the system seamlessly switches to an alternative source, maintaining the aircraft’s integrity and mitigating potential risks.

2. Improved Efficiency

The Lock system plays a crucial role in optimizing the efficiency of the Airbus A320. By providing centralized control and coordination, the system eliminates any conflicting control inputs, enabling smooth and efficient operation of the flight control surfaces.

Moreover, the Autopilot and Autothrust functions, integrated within the Lock system, contribute to fuel efficiency and operational costs. The Autopilot ensures precise flight path adherence, minimizing deviations and optimizing navigation, while the Autothrust system adjusts engine thrust to maintain the desired speeds, reducing unnecessary fuel consumption.

3. Superior Flying Experience

The seamless integration and precise control enabled by the Lock system result in a superior flying experience for both pilots and passengers. Pilots can rely on the system’s consistency and responsiveness, allowing them to focus on other critical aspects of flight operations.

For passengers, the enhanced stability and maneuverability provided by the Lock system contribute to a smoother and more comfortable flight experience. The accuracy of the Autopilot and Autothrust functions ensures a consistent and predictable journey, even in challenging weather conditions.


The Lock system on the Airbus A320 plays a vital role in ensuring the accuracy, reliability, and safety of this iconic aircraft. As an integrated system managing critical flight controls, the Lock system enhances efficiency, optimizes performance, and offers a superior flying experience for all onboard.

With its robust design and seamless integration of Flight Control Computers, Autopilot, and Autothrust, the Lock system on the Airbus A320 sets the standard for modern aviation technology. It is yet another testament to the innovation and engineering excellence of Airbus, propelling the A320 to its position as one of the most successful and trusted aircraft in the world.

For More: What is MAG VAR on Airbus A320? (Magnetic Variation)