What if a crew encountered a slow speed situation before the flaps were fully up after takeoff? This might occur due to a windshear scenario or simply not putting the nose down after thrust reduction. In either case, at some point below VLS, Alpha Floor activated, and the PF followed up with proper selection of TOGA thrust and recovering the speed.
However, once they got everything back under control and resumed their climb there was one puzzling aspect: the speed bug was at Green Dot and not 250. The airplane did not want to accelerate for the climb. There were no speed limits or constraints in the flight plan that might cause that to happen and no system malfunctions. So what was the cause of this mysterious behavior?
As you now know from last weeks discussion, if the target speed is Green Dot, the go-around phase is probably active. In this case, the go-around phase became active when TOGA was selected with the flap lever at 1 or more!
As you read in the quiz answers, the solution is to get out of Go-Around is to either activate the approach, or change the destination and then insert a new cruise altitude. Since their destination did not need to be changed (like it might if you were diverting to an alternate after a go around), activating the approach and re-inserting the cruise altitude is the correct and quick solution. This will result in changing the active flight phase to the CLB and the target speed returning to its 250/ECON climb profile.
Understanding of the operation of Airbus flight phases and their corresponding managed speed values, and use of managed speed will reduce your workload and enable you to operate the airplane at peak efficiency to avoid inadvertent speed errors.
All Airbus pilots should understand the system’s operation. Remember, when things get confusing, no matter what the managed speed value, you can always override with either selected speed or manual thrust lever operation.
As you fly keep an eye on the target speed and observe its behavior as the flight phases change. Use it to your advantage to let the airplane fly the speeds you want without having to manually select them.