A flight yoke is a device used to input movement controls in most kinds of aircraft. It is essentially a handled column that has the ability to articulate forward, backward, and side-to-side, as well as turn like a car's steering wheel. In this way it can be used to direct an aircraft along all three axes, and allow for rotation. A flight yoke operates as part of a flight control system, in combination with pedals that control yaw, which is side-to-side movement, to offer complete control over direction.
Depending on the size of the aircraft, a flight yoke can be mechanically or electronically connected to control surfaces on the wings. Smaller craft typically have cables that stretch from the flaps, ailerons, and other surfaces directly into the cockpit, and are manipulated in direct proportion to movements input through the flight yoke. Mechanical systems depend mainly on physical force applied to the yoke, and in this way are somewhat akin to non-power steering in an automobile. Due to the direct physical connection to parts on the exterior of the craft, tactile feedback is returned back to the pilot through the yoke, offering warnings about problems, such as turbulence or nearing a stall.
Larger craft quickly become too difficult to pilot with only mechanical controls, and so hydraulic systems are often employed to augment pilot input. These hydraulics are connected to servos which respond to pressure from the flight yoke, and cause pistons to actuate. While effective, adding all the necessary hydraulics adds a great deal of weight to an aircraft. This negatively impacts flight characteristics, cargo capacity, and fuel economy.
As a result, commercial airliners and other very large planes have fly-by-wire systems. These replace the direct cabling between the cockpit and flight control surfaces with an electronic interface. Dedicated software interprets pilot inputs from the flight yoke, and correspondingly stimulates actuators on the control surfaces, moving the flaps as appropriate. Often fly-by-wire systems have electronic feedback capabilities, which, for instance, cause the yoke to begin shaking when nearing a stall, simulating a traditional flight control system.
In flight simulators, it is possible to use a yoke in place of a joystick or other control peripheral. Designs range from simple home devices that only superficially reproduce a real flight yoke, to sophisticated flight control simulations that mimic the same feel and feedback as in real aircraft. Flight yokes used in commercial and military training are virtually indistinguishable from the real thing in appearance and operation.
