Why Fly-By-Wire Has Become the Premier Control System

Over the years, the means by which pilots have operated various aircraft control elements have changed drastically. Early designs relied entirely upon mechanically operated systems which demanded a significant force output from pilots. As the aerodynamic demands of airplanes became non-negligible, engineers elected a hydro-mechanical configuration to relieve operator fatigue. This design principle would continue to dominate the market until the full roll-out of the fly-by-wire (FBW) system in the 1970s. This revolutionary system is now the standard on many commercial and military planes today. In this blog, we will discuss the components and operation of fly-by-wire systems.

The FBW system uses a series of sensors, including gyroscopes and accelerometers, to relay positional and speed data to the flight control computer (FCC), which then modulates the various control elements to match the desired output set forth by the pilot or autopilot. These processes occur throughout the duration of the flight and transpire at incredible speed. The calculations also vary depending on the phase of flight. For example, during takeoff, the FCC will optimize for lift and thrust before switching to a more efficient mode during cruising altitude. At any time during the flight, the pilot may initiate a step climb or descent in order to improve fuel efficiency. This command will be immediately processed by the flight management system and the correct output will be applied.

In the early days of the FBW system, other flight control systems were also installed to provide redundancy in case of failure. Over time, engineers and operators embraced the cost and safety benefits of switching to a purely FBW system, and instead installed more sensors and computers to increase redundancy. Most commercial aircraft have two copies of critical elements employed, with limited backup in the case that all three fail. This configuration speaks to the trust that aviators have in this highly-effective system.

From a safety, comfort, and economic standpoint, FBW systems outperform their hydro-mechanical counterparts in the majority of metrics. With constant input from sensors, the FCC can quickly recognize signs of a jam and modulate the function of the afflicted flight surface to provide relief. Additionally, the flight controller will also prevent the pilot from performing maneuvers that exceed the operational parameters of the aircraft, including the angle of attack and speed. With fewer mechanical components, FBW systems also help save on maintenance time and increase longevity.

The chief disadvantage to fly-by-wire systems compared to legacy configurations is the installation cost. This configuration is also more technically advanced than hydro-mechanical or cable options, requiring a higher level of expertise from maintenance personnel and potentially elevating costs in terms of part replacement. Pilots must also add automated control systems to the list of instruments necessary to monitor. Although this further splits the flight crew's attention, it provides them with critical and real-time information about the various control surfaces. Still, many commercial and military operators continue to push toward the adoption of fly-by-wire systems due to their safety and economic profile.

When you are looking to upgrade or replace fly-by-wire components, Aerospace 3Sixty has you covered with a diverse inventory of new, obsolete, and hard-to-find parts. Using our website, customers may find their exact requirements by using our advanced search engine or convenient parts catalogs. Upon finding a product you are interested in, you may submit an Instant RFQ form to initiate the purchasing process at any time. As an AS9120B, ISO 9001:2015, and FAA AC 00-56B accredited enterprise with a NO-CHINA Sourcing pledge, we maintain robust standards to ensure the quality of our inventory and we would be happy to answer any questions you may have.

1. mark williams
2. Posted on January 19, 2023
aviation

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