Autobrake

Anautobrakeis a type of automatic wheel-basedhydraulic brakesystem for advancedairplanes.The autobrake is normally enabled duringtakeoffandlandingprocedures, when the aircraft's longitudinal deceleration system can be handled by the automated systems of the aircraft itself in order to keep thepilotfree to perform other tasks.

Landing

While landing, the autobrake can help to free up the pilot to allow monitoring other systems (such as the execution of thelanding flare). There are usually several settings for the rate of deceleration. The selection of these settings are normally undertaken on the aircraft instrument panel before landing. Aircraft have multiple autobrake settings, with higher settings providing more aggressive braking forces. These are set based on factors such as runway length or desired exit point from the runway.

When the landing feature of the autobrake is engaged, the aircraft automatically engages pressurized wheel braking upon touchdown to thelanding surface.During the roll out, application of the brake pedals transfers control back to the pilot.

One of the main advantages of engaging the autobrake as opposed to manually pressing on brake pedals is the uniform deceleration mechanism of the autobrake. The aircraft automatically decelerates at the selected level regardless of other factors, such as aircraftdragand other deceleration methods such as deployment ofthrust reversersorspoilers.

Rejected takeoff

Whiletaking off,the aircraft's autobrake can be set to therejected takeoffmode, commonly indicated on an aircraft instrument panel as RTO. In case of the Airbus A300-600 and A320 family models, "MAX" mode is set. In RTO setting, the aircraft monitors certain variables, depending on the autobrake model. Most autobrakes engage RTO braking if the pilot returns thethrottleto the "idle" position, or ifreverse thrustis engaged. Other autobrake systems may monitor critical flight controls for failures.