What is DED on Boeing 737? (Dead Ended Shield)

The Dead Ended Shield (DED) is an important safety feature found on the Boeing 737 aircraft. It is designed to protect critical flight control systems from potential electromagnetic interference (EMI) that may be caused by external sources. The DED consists of a shielded enclosure that contains various electronics and wires, preventing any unwanted interference that could affect the aircraft’s performance or control.

In this article, we will delve deeper into understanding the purpose and functionality of the Dead Ended Shield on the Boeing 737. We will explore its significance in maintaining the safety and integrity of the aircraft’s flight control systems.

The Importance of Dead Ended Shield (DED)

The Dead Ended Shield plays a critical role in protecting the flight control systems of the Boeing 737 from potential electromagnetic interference. This interference can be caused by a variety of external sources, including radio frequency (RF) signals, static charge buildup, and other electrical equipment both inside and outside the aircraft. These sources of interference can disrupt the normal operation of the aircraft’s flight control systems, leading to potentially dangerous situations.

The DED acts as a protective barrier that prevents external electromagnetic signals from infiltrating the flight control systems. It achieves this by enclosing the critical electronics and wires within a shielded enclosure. This shielded enclosure is essentially a Faraday cage, which is made of conductive material that blocks electromagnetic fields.

The DED is strategically positioned within the aircraft to ensure that all critical flight control systems are shielded from potential interference. This includes the aircraft’s fly-by-wire system, which relies on electronically controlled flight surface actuators. These actuators play a crucial role in maneuvering the aircraft by controlling the movement of the flight surfaces such as the ailerons, elevators, and rudder.

By protecting the fly-by-wire system and other critical flight control systems, the DED ensures the reliability and safety of the aircraft during all phases of flight. It helps maintain stable and precise control, reducing the risk of malfunctions and providing a smooth flying experience for both the crew and passengers.

The Functionality of Dead Ended Shield (DED)

To better understand how the Dead Ended Shield functions, let’s take a closer look at its design and construction. The DED is made of a conductive material, such as aluminum or copper, which forms an enclosed structure around the critical flight control systems. This structure is specifically engineered to block external electromagnetic signals and prevent them from reaching the internal components.

The shielding effectiveness of the DED is measured in terms of its ability to attenuate electromagnetic signals. This is usually expressed in decibels (dB), with higher dB values indicating greater shielding effectiveness. The DED is designed to provide a high level of shielding, ensuring minimal interference with the flight control systems.

Additionally, the DED is grounded to dissipate any electromagnetic energy that may be picked up by the shield. This grounding helps divert the unwanted electromagnetic signals away from the critical systems and towards a safe discharge point, preventing them from causing interference.

The effectiveness of the DED is carefully tested and validated during the aircraft’s certification process. This involves subjecting the aircraft to various electromagnetic scenarios to ensure that the DED adequately shields the flight control systems. The electromagnetic compatibility (EMC) tests assess the aircraft’s ability to operate safely in the presence of electromagnetic fields generated by external sources.

The Significance of Dead Ended Shield (DED)

The Dead Ended Shield is crucial in ensuring the continued safe and reliable operation of the Boeing 737 aircraft. It serves as a safeguard against potential electromagnetic interference, which can have detrimental effects on the performance and control of the flight control systems. By implementing the DED, Boeing maintains a high level of aircraft integrity and enhances safety for both crew and passengers.

In conclusion, the Dead Ended Shield plays a vital role in protecting the Boeing 737’s flight control systems from external electromagnetic interference. Its design, construction, and grounding help attenuate unwanted signals and ensure the reliability of the aircraft’s critical systems. By understanding and appreciating the significance of the Dead Ended Shield, we can better grasp the complex mechanisms that contribute to the safety and efficiency of modern aircraft.

For More: What is DADC on Boeing 737? (Digital Air Data Computer)