Instead of the mechanical systems that used to transmit control impulses around a plane, fly-by-wire (FBW) systems convert movements of the controls into electrical impulses. These signals are sent to flight-control computers that reconvert the electrical impulses into instructions for control surfaces like wing flaps or the tail. Potentiometers, or pots, in the control surfaces measure their position and transmit that data back to the flight computer.
Once a control surface is in the correct place, the computer freezes the component, ensuring the pilot’s commands are followed. This electronic system, while complex, not only makes the controls more precise but also means aeroplanes no longer have to be fitted with the cranks, gears, pulleys and cables on which older aviation systems relied.
Fly-by-wire systems also make the aircraft substantially safer to fly, as the flight computers can be programmed to carry out adjustments to control surfaces automatically. This helps keep the flight much more stable, as the plane is – to some extent – ‘helping’ fly itself. This is largely as a result of gyroscopes fitted in the aircraft which are connected to the on-board computers. The gyroscopes measure fluctuations in pitch, roll and yaw and, if the plane strays from its pre-programmed settings, they move too, triggering the computer to compensate.