"Why did the throttle retract after a manual override?" is one of them.
easily answered I think? With the A/T engaged, levers would return to idle if opened manually due to faulty radalt signal. When the A/T was disengaged, they did not.
I look at the issue from an "interaction designer" point of view. (I am involved in software design for a living.) The
design issue I see is that the human override only had a temporary effect; Boeing might have designed the system so that autothrottle would disengage when the pilot moved the throttle manually.
I know each of those choices creates its own issues; an accidental disengagement of AT creates problems too. The difference for the pilot would be:
- move thrust lever and press button to engage AT again (if desired)
- press button to disengage AT before moving thrust lever
What would be safer/more natural for a pilot?