HOTAS

F-16 simulator side-stick controller functional allocation

F-16 simulator throttle functional allocation

HOTAS, an acronym of Hands On Throttle-And-Stick, is the name given to the concept of placing buttons and switches on the throttle lever and flight control stick in an aircraft's cockpit, allowing pilots to access vital cockpit functions and fly the aircraft without having to remove their hands from the controls. Application of the concept was pioneered with the Ferranti AIRPASS radar and gunsight control system used by the English Electric Lightning^[1][2] and is widely used on all modern fighter aircraft such as the F-16 Fighting Falcon, the A-10A/A-10C and others.

HOTAS is a shorthand term which refers to the pattern of controls in the modern fighter aircraft cockpit. Having all critical switches on the stick and throttle allows the pilot to keep both "hands on throttle-and-stick". Used in combination with a Heads-Up Display (HUD), the pilot can focus on flying the aircraft, manipulating sensors, and engaging targets rather than looking for controls in the cockpit. The goal is to improve pilots' situational awareness, their ability to manipulate switch and button controls in turbulence, under stress, or during high G-force maneuvers, to improve reaction time, to minimize instances when hands must be removed from one or the other of the aircraft's controls to use another aircraft system, and reduce total time spent doing so.

This system gives the pilot the ability to manipulate all the radar's important functions without moving the hands away from the stick or throttle.^[3] Other functions are incorporated such as radio communications switch, chaff and flare countermeasure activation, speed brake controls, nose wheel steering, and aerial refueling disconnect. Each aircraft is unique and has a design specific to the air frame. For instance, the F-15E Strike Eagle throttle incorporates FLIR options as opposed to the F-16 simulator diagrams as shown.^[4]

Voice

In the modern military aircraft cockpit the HOTAS concept is sometimes enhanced by the use of Direct Voice Input to produce the so-called "V-TAS" concept.

Viewing direction

A further enhancement are helmet mounted display systems such as the "Schlem" used in the MiG-29 and Su-27, which allow the pilot to control various systems using his line of sight, and to guide missiles by simply looking at the target.

Steering wheels

The concept has also been applied to the steering wheels of modern open wheel racecars, like those used in Formula One^[5] and the Indy Racing League.

Simulators

HOTAS has been adapted for game controllers used for flight simulators (a popular system is the Falcon 4.0 based on the F-16)^[6] and in cars equipped with radio controls on the steering wheel.

References