Definition
A flight control system in which the pilot's control inputs are transmitted to the control surfaces electronically through wires and computers rather than through mechanical cables, rods, or hydraulic linkages. Sensors detect the pilot's stick or yoke movements, computers interpret those inputs (often applying limits and stability adjustments), and electrical signals drive actuators that move the ailerons, elevators, and rudder.
Plain English
Instead of cables and pulleys connecting the controls to the wings and tail, the pilot's inputs travel as electrical signals through wires to computers, which then move the control surfaces.
Context Anchor
Seen in modern aircraft flight-control systems, maintenance descriptions, cockpit system checks, and discussions of flight-control failures or backups.
Derivation
The name comes from the older term 'fly-by-cable,' which described traditional mechanical control runs. 'Wire' here refers to electrical wiring — the signal path is now electrons in a wire instead of tension in a steel cable.
Why Pilots Care
Fly-by-wire systems can apply built-in flight envelope protections, prevent over-stressing the airframe, and reduce pilot workload — but they also mean the controls behave differently than cable-and-pulley systems, especially when degraded modes are active. Maintenance technicians must understand that troubleshooting involves electrical, software, and actuator components rather than rigging cables.
Intuition Check
Fly-by-wire does not mean the airplane flies itself. It means the pilot’s commands are sent electrically before the aircraft’s controls move.
Example Sentence 1
The technician traced a fly-by-wire fault to a failed signal from the side-stick transducer, not to anything in the actuator itself.
Example Sentence 2
Maintenance on a fly-by-wire aircraft includes checking the integrity of the wiring that carries control signals to the aileron actuators.