What is ELEC on Boeing 737? (Electrical)

The Boeing 737 is one of the most popular and widely used aircraft in the world. It has been serving airlines since its introduction in the late 1960s and continues to be a reliable workhorse in the aviation industry. As with any modern aircraft, the Boeing 737 relies heavily on electrical systems to ensure its safe and efficient operation. In this article, we will explore the role of electrical systems in the Boeing 737 and how they contribute to its overall functionality.

The Importance of Electrical Systems

While the Boeing 737 may be known for its impressive aerodynamics and powerful engines, the role of electrical systems should not be underestimated. Electrical systems play a crucial role in various aspects of the aircraft’s operation, from powering essential flight instruments to controlling critical systems.

The electrical systems on the Boeing 737 are responsible for providing power to a wide range of components, including lights, avionics, and other onboard systems. The ELEC system, short for Electrical, ensures the continuous supply of electricity to these components, allowing them to function as intended.

The ELEC System on the Boeing 737

The ELEC system on the Boeing 737 is a complex network of components and circuits that work together to provide electrical power throughout the aircraft. It consists of generators, batteries, control panels, and various other components that are strategically distributed across the aircraft.

Let’s delve deeper into some of the major components of the ELEC system:


The generators are responsible for producing electrical power during the aircraft’s operation. The Boeing 737 typically has two generators, each driven by one of the aircraft’s engines. These generators convert mechanical energy from the engines into electrical energy, which is then distributed throughout the aircraft.

Having multiple generators ensures redundancy in case one generator fails. This redundancy is crucial for the safe operation of the aircraft, as it provides a backup power source in case of emergencies or malfunctions.


In addition to generators, the Boeing 737 is equipped with batteries that serve as a backup power source. These batteries provide electrical power when the generators are not operational, such as during engine shutdown or in the event of a generator failure.

The batteries also play a crucial role during the aircraft’s startup. They provide the initial power required to start the engines and activate the generators. Once the engines are running, the generators take over the power supply, and the batteries are recharged.

Control Panels

The ELEC system on the Boeing 737 includes control panels that allow the flight crew to monitor and control the electrical systems. These control panels provide information about the status of various electrical components and allow the crew to take appropriate actions in case of abnormalities or failures.

The crew can access the control panels through the aircraft’s cockpit, where they have a comprehensive view of the electrical system’s performance. This ensures that any issues with the electrical systems can be identified and addressed promptly, minimizing the risk of in-flight incidents.

The Role of Electrical Systems in Flight

Now that we have a basic understanding of the ELEC system on the Boeing 737, let’s explore some of the key functions and systems it powers during flight:

Flight Instruments

Flight instruments, such as the altimeter, airspeed indicator, and attitude indicator, heavily rely on electrical power. These instruments provide crucial information to the pilots, allowing them to monitor the aircraft’s altitude, speed, and orientation.

Without a continuous supply of electricity, these vital instruments would be rendered useless, severely compromising the pilots’ ability to navigate the aircraft safely. The ELEC system ensures that these instruments are powered throughout the flight, enabling the crew to make informed decisions and respond to any changes in flight conditions.


Avionics systems, including communication, navigation, and surveillance equipment, are also reliant on electrical power. The ELEC system provides the necessary power to ensure the uninterrupted operation of these systems, allowing the aircraft to communicate with air traffic control, navigate accurately, and maintain situational awareness.

These avionics systems play a crucial role in the overall safety and efficiency of the aircraft, especially during critical phases of flight, such as takeoff and landing. The ELEC system’s reliability is essential to ensure that these systems function as intended, minimizing the risk of communication or navigation failures.

Onboard Systems

Various onboard systems, including lights, air conditioning, and cabin pressurization, rely on electrical power provided by the ELEC system. These systems contribute to the comfort and well-being of passengers and crew members throughout the flight.

For example, the cabin lighting is crucial for passenger safety and convenience. The ELEC system ensures that the lights are functional, allowing passengers to move around the cabin safely and comfortably, even during nighttime or low-visibility conditions.

The air conditioning and pressurization systems, powered by the ELEC system, provide a comfortable and controlled environment within the aircraft. These systems help regulate the temperature and cabin pressure, ensuring a pleasant flight experience for everyone on board.

The Continuous Advancement of Electrical Systems

As aircraft technology continues to advance, so do electrical systems. New generations of the Boeing 737, such as the 737 MAX, feature enhanced electrical architectures that offer improved efficiency, increased reliability, and advanced monitoring capabilities.

For example, the 737 MAX incorporates the Advanced Electrical Power Distribution System (AEWDS), which provides greater control and monitoring capabilities for the electrical systems. This system features intelligent monitoring and fault detection, allowing for proactive maintenance and enhanced overall system performance.

The continuous advancement of electrical systems not only improves the reliability and performance of the aircraft but also contributes to enhanced safety and reduced maintenance costs. These advancements enable airlines to operate more efficiently and provide a better flying experience for passengers.

In conclusion, the electrical systems on the Boeing 737 play a vital role in the aircraft’s operation. The ELEC system ensures a constant supply of electrical power to various components and systems, allowing for safe and efficient flight. From powering critical flight instruments to controlling onboard systems, electrical systems are an essential aspect of the Boeing 737’s functionality. As technology progresses, further enhancements to these electrical systems will continue to pave the way for the future of aviation.

For More: What is DFDR on Boeing 737? (Digital Flight Data Recorder)