Originally Posted by
CA1900
Yes, they do. As long as the AT switch is on (which is normally would be until the autopilot is disconnected for landing, even if it's in ARM mode not actively doing anything), the system will push the thrust up automatically if needed.
Say they were given a descent to 4k and told to slow to 180 while doing 230-250. They’d spin the airspeed knob to 180 and throw the speed brakes to help with the descent. New FO is told to slow toward up bug before asking for flaps.
If he forgot, the airplane is going to do what you tell it…descend to 4k and slow to 180. Auto throttles won’t do anything until 170-180 and by then you’re 20 kts or so below up bug.