What is EFCS on Airbus A320? (Electronic Flight Control System)

The Electronic Flight Control System (EFCS) on the Airbus A320 aircraft is a crucial component of the fly-by-wire technology that powers modern aircraft. This advanced system replaces traditional mechanical controls with a digital interface, enhancing the aircraft’s maneuverability, safety, and overall performance. By using electronic signals to transmit pilot inputs to flight control surfaces, the EFCS optimizes control response and provides a seamless flying experience.

The EFCS consists of several key components, including the flight control computers, the side sticks, and the flight control laws. Together, these components work harmoniously to ensure precise control of the aircraft during all phases of flight.

The Flight Control Computers

The flight control computers are the brains behind the Airbus A320’s EFCS. There are three redundant computers, known as the dual-digital flight control computers (DFCC), which constantly monitor and analyze data from various sensors throughout the aircraft. These sensors include the angle of attack sensors, accelerometers, and other vital inputs.

The DFCCs receive pilot inputs from the side sticks and determine how those inputs should be translated into control surface movements. They then send the appropriate commands to the flight control surface actuators, ensuring a precise and accurate response. The redundant nature of the computers ensures that even in the event of a failure, the system remains functional, guaranteeing the highest level of safety.

The Side Sticks

The side sticks in the Airbus A320 are the primary means through which pilots input their commands to the EFCS. Unlike traditional control yokes, which are centrally located in front of the pilots, the A320’s side sticks are located on the outer edges of the cockpit. This arrangement allows for better visibility and more intuitive control.

The side sticks are equipped with force transducers that measure the amount of force applied by the pilots. These transducers convert the pilot’s commands into electrical signals, which are then sent to the flight control computers. The EFCS interprets these signals and adjusts the control surfaces accordingly, providing a seamless interface between the pilots and the aircraft.

The Flight Control Laws

The flight control laws form the heart of the Airbus A320’s EFCS. These control laws define the aircraft’s behavior in response to various flight conditions and ensure stability, control, and protection against potentially dangerous situations.

The Airbus A320 has three primary flight control laws: Normal Law, Alternate Law, and Direct Law. In Normal Law, the EFCS offers automatic pitch and bank angle protection, ensuring that the aircraft does not exceed its operational limits. It also provides envelope protection and attitude stabilization. Normal Law is the default mode during most flight operations.

In the event of system failures or certain abnormal conditions, the EFCS may transition to Alternate Law. This mode enables pilots to retain flight control by introducing some manual inputs. However, certain flight envelope protections may be lost, requiring pilots to adhere to manual control limitations.

In the rare event of multiple system failures or complete loss of the EFCS, the Airbus A320 can operate in Direct Law. In this mode, the flight control surfaces move mechanically in response to pilot inputs, bypassing the digital interface of the EFCS. Direct Law provides pilots with direct control but without the added benefits of the EFCS.


The Electronic Flight Control System (EFCS) on the Airbus A320 plays a crucial role in enhancing the aircraft’s maneuverability, safety, and performance. By employing digital technology to replace traditional mechanical controls, the EFCS offers precise and efficient control in all flight conditions. The flight control computers, side sticks, and flight control laws work cohesively to ensure a seamless interface between the pilots and the aircraft, providing a smooth and enjoyable flying experience.

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