On the “Perf Climb” page of the MCDU (Multifunction Control and Display Unit) the “EXPEDITE” field displays the time in UTC the aircraft predicts it would reach the altitude displayed on that same page. If an Expedited Climb is selected by the pilots this will be flown at Green Dot. Maximum Endurance speed will vary from Green Dot to Green Dot + 10 kt approximately depending on the weight of the aircraft, its altitude and the OAT (Outside Air Temperature). On Airbus aircraft, Green Dot also corresponds to the final takeoff safety speed.įor enroute holding, if this is no specified speed restriction, the FMGEC will target “Maximum Endurance Speed” which equates to approximately Green Dot Speed in clean configuration. In the event of a loss of one or more engines, Green Dot represents the best Engine-out operating speed in clean configuration A higher ratio means increased fuel efficiency, improved climb performance and, importantly, the best glide ratio (more on that below). Lift-to-drag ratio (also know as “L/D”) refers to the amount of lift generated by the aircraft, divided by its drag. “Green Dot” (sometimes referenced simply as “GD”) allows the pilots at any time to instantly know what the aircraft’s best lift-to-drag ratio speed is. With all engines operating the Green Dot speed corresponds approximately best lift-to-drag ratio speed. Green Dot Speed (so-called because it is displayed to the pilots as green dot on the Primary Flight Display speed tape) symbolizes the “engine-out operating speed in clean configuration” which is the speed allowing the highest climb gradient with one engine inoperative in clean configuration.

A350 take off performance calculator