Air France 447, Colgan 3407, Air Algerie 5017 (Swift Air), West Air 294.
Loss of control accidents happening in darkness - involving fatigue.
From my experience as an instructor and examiner, high altitude loss of control scenarios (particular in darkness) are critical. One thing that can not be simulated in the simulator is fear.
It is essential to avoid the fully loss of controls incidents, since the likelihood of recovery in my opinion is 50/50.