If the
NTSB report's nomenclatures are close or correct, there is one "lever" that could cause complete loss of T/R control and be associated with a scheduled inspection task. The lever (walking beam) is located in the aft hatrack area where the TR servo attaches on one end and the TR long control tube on the other. And is not visible at all once the aircraft is closed up.
And just to reiterate what FltMech said: It can happen to anyone regardless of skill, experience, and even 135/121 ops with all the rules. Nothing worse than the gut punch you feel when something like this happens from a maintenance perspective.