What is DFCS on Boeing 737? (Digital Flight Control System)

The Digital Flight Control System (DFCS) on the Boeing 737 is a critical component that plays a crucial role in the aircraft’s flight control and maneuverability. As the name suggests, the DFCS is a digital system that replaces traditional mechanical control systems, offering numerous advantages in terms of precision, reliability, and safety.

The DFCS integrates various control functions and automation systems to enhance the pilot’s ability to control the aircraft effectively. It provides a direct interface between the pilot’s inputs and the control surfaces of the aircraft, making it a vital part of the overall flight control architecture. Let’s explore the features and benefits of the Digital Flight Control System on the Boeing 737 in more detail.

Digital Flight Control System: Features and Benefits

The DFCS on the Boeing 737 offers several features that contribute to its superior performance and safety. Here are some key features of the system:

1. Fly-by-Wire Technology

One of the significant advantages of the DFCS is its incorporation of fly-by-wire technology. Instead of relying on traditional mechanical linkages, the DFCS uses electrical wires to transmit control signals from the pilot’s inputs to the control surfaces. This technology provides a more precise and responsive control mechanism, enhancing the aircraft’s maneuverability.

With fly-by-wire technology, the DFCS can also offer advanced features such as envelope protection and auto-trim. The envelope protection system prevents the pilot from exceeding the aircraft’s operational limits and provides an extra layer of safety. Additionally, the auto-trim feature automatically adjusts the control surfaces to optimize the aircraft’s performance, reducing the workload for the pilot.

2. Redundancy and Fault Tolerance

An essential aspect of the DFCS is its redundancy and fault tolerance. The system is designed with multiple channels and redundant components to ensure that even in the event of a failure, the aircraft’s flight control remains intact. In case a failure occurs, the system automatically switches to another channel, minimizing the impact on the aircraft’s controllability.

Redundancy in the DFCS enhances the overall safety of the aircraft by reducing the likelihood of a single-point failure. This design approach ensures that even if one channel or component fails, the system can still operate within its limitations, allowing the pilot to safely control the aircraft.

The Role of Digital Flight Control System in the Boeing 737

The DFCS is a critical system that influences various aspects of the Boeing 737’s flight control and performance. From takeoff to landing, the system actively assists the pilot in maneuvering the aircraft, ensuring a smooth and controlled flight experience.

1. Primary and Secondary Flight Controls

The DFCS on the Boeing 737 manages both the primary and secondary flight control surfaces. The primary flight controls include the ailerons, elevators, and rudder, which are responsible for roll, pitch, and yaw control respectively. These surfaces are directly controlled by the pilot’s inputs and play a crucial role in maintaining the stability and control of the aircraft.

The secondary flight controls, on the other hand, consist of flaps and spoilers. The DFCS ensures proper deployment and positioning of these surfaces based on the aircraft’s configuration and flight phase. The accurate control of the secondary flight controls optimizes lift and drag characteristics, contributing to fuel efficiency and overall performance.

2. Auto-Throttle System

The Digital Flight Control System also integrates with the Boeing 737’s auto-throttle system. The auto-throttle system automatically adjusts the engine thrust based on the aircraft’s speed and other factors, reducing the workload for the pilots during various phases of flight.

By working in conjunction with the auto-throttle system, the DFCS ensures that the aircraft maintains the desired speed and performance parameters set by the pilot. This collaboration between systems enhances fuel efficiency, reduces pilot workload, and optimizes performance throughout the flight.


The Digital Flight Control System (DFCS) on the Boeing 737 revolutionizes the aircraft’s flight control capabilities by utilizing digital, fly-by-wire technology. With its advanced features, redundancy, and fault tolerance, the DFCS enhances safety, maneuverability, and performance. The system plays a crucial role in managing the primary and secondary flight controls, as well as collaborating with the auto-throttle system for optimized flight performance. Overall, the DFCS is a testament to the continuous innovation and improvement in aviation technology, contributing to safer and more efficient flights on the Boeing 737.

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