What does "fly-by-wire" mean in modern aircraft?

"Fly-by-wire" refers to a system in modern aircraft that utilizes electronic signals to control flight operations. This means that instead of traditional mechanical linkages and hydraulics, the pilot’s control inputs are transmitted through electronic systems, which then interpret those inputs and command the flight control surfaces accordingly.

This technology provides several advantages, including improved precision in control, the ability to integrate advanced flight control laws and autopilot functions, and reduced weight by eliminating much of the mechanical hardware. Additionally, fly-by-wire systems can incorporate safeguards that enhance safety and performance, such as limiting the aircraft's performance to safe parameters and offering automatic stability enhancements.

In contrast, systems that rely solely on hydraulic controls involve more traditional mechanisms with physical linkages, while those based only on pilot mechanical input would not incorporate the advanced assistive technologies afforded by fly-by-wire systems. A backup system for emergencies operates differently, providing redundancy rather than being the primary control method utilized during routine flight operations.