What is GCU on Airbus A320? (Generator Control Unit)

The Generator Control Unit (GCU) is a critical component of the electrical system on the Airbus A320 aircraft. As the name implies, it is responsible for controlling and regulating the aircraft’s generators, which provide electrical power to various systems and equipment on board. The GCU ensures that the generators produce the required voltage and frequency, while also protecting them from overload or malfunction.

Let’s dive deeper into the functions and importance of the Generator Control Unit on the Airbus A320.

Functions of the Generator Control Unit

The Generator Control Unit performs several key functions to ensure the proper operation of the generators on the Airbus A320. These functions include:

1. Voltage and Frequency Regulation: The GCU monitors the voltage and frequency produced by the generators and adjusts them to the required levels. It ensures that the electrical power distributed throughout the aircraft is within the specified limits, preventing any damage to the electrical systems or equipment.

2. Load Management: The GCU manages the distribution of electrical loads among the generators, ensuring that each generator is operating efficiently and not overloaded. It continuously monitors the electrical demand from various systems and equipment and adjusts the power supply accordingly.

3. Fault Detection and Protection: The GCU is equipped with advanced fault detection systems that constantly monitor the generators for any abnormal conditions or malfunctions. In the event of a fault or overload, the GCU takes immediate action to protect the generators by disconnecting them from the electrical bus and isolating the fault.

Importance of the Generator Control Unit

The Generator Control Unit plays a crucial role in maintaining the safe and efficient operation of the electrical system on the Airbus A320. Here’s why it is so important:

1. Safety: The GCU ensures that the generators produce stable and reliable electrical power, preventing any potential hazards caused by voltage or frequency fluctuations. It also protects the generators from overload and isolates faults, reducing the risk of electrical failures and subsequent system malfunctions.

2. System Performance: By regulating the voltage and frequency, the GCU maintains the electrical systems’ optimal performance. This ensures that all systems and equipment, such as avionics, lighting, and communication systems, receive the required power for their efficient and uninterrupted operation.

3. Redundancy and Reliability: The Airbus A320 aircraft is equipped with multiple generators for redundancy. The GCU ensures the seamless integration and synchronization of these generators, allowing for a reliable and continuous power supply even in the event of a generator failure. It quickly detects any faults and isolates them, minimizing the impact on the overall electrical system.

The GCU’s importance also extends to the overall safety and functionality of the aircraft. It plays a vital role in the proper operation of other critical systems, such as the emergency power supply and the auxiliary power unit.


The Generator Control Unit (GCU) is a fundamental component of the electrical system on the Airbus A320 aircraft. It performs essential functions, including voltage and frequency regulation, load management, and fault detection and protection for the generators. The GCU ensures the safety, performance, redundancy, and reliability of the electrical system, contributing to the overall safety and functionality of the aircraft.

Understanding the role and significance of the Generator Control Unit highlights the complexity and precision of the systems and components that keep modern aircraft operating smoothly. The GCU exemplifies the advanced engineering and technology behind the Airbus A320, which has made it one of the most popular and trusted aircraft in the world.

For More: What is ADIRU on Airbus A320? (Air Data Inertial Reference Unit)