Flight control modes: Difference between revisions

Revision as of 17:19, 29 December 2024

Revision as of 18:47, 13 January 2025

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===Direct law===

''Direct law'' (DIR) introduces a direct stick-to-control surfaces relationship:<ref name="SmartCockpit - A330 Flight Controls"/> control surface motion is directly related to the sidestick and rudder pedal motion.<ref name="urlCrossing the Skies » Fly-by-wire and Airbus Laws"/> The trimmable horizontal stabilizer can only be controlled by the manual trim wheel. All protections are lost, and the maximum deflection of the elevators is limited for each configuration as a function of the current aircraft centre of gravity. This aims to create a compromise between adequate pitch control with a forward center of gravity (C.G.) and not-too-sensitive control with an aft C.Gcenter of gravity.<ref name="A320AFM">Airbus A320 AFM (requires page number, publisher, etc)</ref>

DIR is entered if there is failure of three inertial reference units or the primary flight computers, faults in two elevators, or flame-out in two engines (on a two-engine aircraft) when the captain's primary flight computer is also inoperable.<ref name="SmartCockpit - A330 Flight Controls"/>