A320 Flight Control Laws

 
Alpha Floor Mode

Alpha floor is an automatic thrust setting based upon AOA (angle
of attack) and decelaration rate.

Alpha floor counters the effects of high wind gradients during an
approach. When the radio altimeter is indicating an altitude greater
than 100 feet and the angle of attack is fifteen degrees or greater,
Alpha floor is automatically engaged. The result is the automatic
application of thrust.

Alpha floor can be disabled by using a disconnect button on the throttle
levers, disenalbling the autothrottle, physically placing the throttles
in the idle detent position.