Originally Posted by
RangerNS
There is also 3) (after knowing about the procedure, and correctly trying to implement the procedure)
3) Being physically able to manipulate the controls.
True. Though it may be rightly argued that Boeing expected the crews to continue applying other normal procedures to maintain control of the aircraft during execution of an emergency procedure. The crew leveling off at low altitude with the throttles firewalled and the overspeed clacker sounding away may not be something that was anticipated, and perhaps rightly so, since the crew would be expected to take action to keep the aircraft below Vmo whenever they are flying.
Now I don't think the blame lies with the crew in the second crash, but I'm pointing that out to say that it was a convergence of events. The normal trim runaway emergency procedure SHOULD have worked in this case, just as it SHOULD work properly for a more 'normal' trim runaway. The fact that it didn't is due to aircraft AND crew/training AND human factors.