AF447
There is evidence that all three were tired.
Robert reported upon his return that he did not sleep well but only "dozed a little."
His seat remained fully back and to the left in the parked position the entire time.
Robert should have taken over at the first sign that Bonin wasn't flying as required "you're going up so go down" but that was strictly against the AF culture.
In fact, few (if any) PMs anywhere are trained to take over the airplane.
I've never heard of it being practised in the simulator or as part of actual hands-on training exercise.
In the future, it must be, for the ability of the average pilot to fly manually without any little green bars to follow is diminishing with time.
Soon, the engineers will be able to address the leading cause of accidents today - LOC - in flight due to the pilots not being able to handle the situation.
They will do this by removing the pilots and frankly we will have deserved it if we don't take action.
The alternative is for pilots to become pilots again and learn to control and recover the airplane from extreme situations.