Flight control system mode and method providing aircraft speed control through the usage of momentary on-off control

A longitudinal control law is designed to optimize the flying qualities when aircraft is set to approach configuration, i.e. when the flap lever is set to the landing position and landing gears are locked down. Under such circumstances, the effort of trimming the aircraft speed can be extremely reduced by the usage of a momentary on-off switch or other control in the sidestick, instead of or in addition to a conventional trim up-down switch, making easier the task of airspeed selection by the pilot. This control law provides excellent handling qualities during approach and landing, with the benefit of not needing or using radio altimeter information in safety-critical applications.