yanrair, #2750,
‘i don't think runaway stab is avoidable on any type?’
Any solution would involve compromise, uncertainty, degree of acceptability, the relative contributions of the man-machine system (in context), and the outcome; as discussed above with Tomaski, #2791.
Training alone is not a solution, a component maybe, providing the consequences of the range of likely human behaviour (judgement) and worst case system malfunction enable recovery.
‘… the aircraft basic trim state. Its the trim moving in such a way as to cause the plane to deviate from its desired path -uncommanded -which tells you its misbehaving.‘
You appear to misjudge the mechanism of stick force feel and flight path perhaps biased by a unique event.
It is normal when maintaining level flight with change in airspeed (maintaining stick position ~) which will change stick force, requiring trim adjustment, a first-order deduction, check speed / trim the aircraft.
Aircraft flight path deviation implies stick movement, but not necessarily a change in trim if power is adjusted and speed maintained; we should not deduce a trim malfunction if speed or power are incorrect for stable fight.
For severe trim malfunctions the crew must be alerted to the condition and action as necessary, then your view of intervention can be applied - minor training task; an if-then drill.
The Max accidents identify the hazards of assuming that crew’s will recognise situations in time to take action, but misjudged against the backdrop of unforeseen / unforeseeable influences on human capability.
Re #2762, ‘I hope we all learned from the AF 447 how not to fly with unreliable IAS. And Turkish Airlines at AMS that an auto-thrust failure should be a non event.‘
Certification authorities have readjusted expectations pitot equipment in rare icing conditions - equipment changed and all aircraft modified.
Re AMS, see full accident report - appendices, which identified a mismatch between what Boeing assumed (sim testing) and more realistic pilot intervention time and height loss as established by the investigation. A familiar theme ?
We cannot expect human intervention to mitigate an inadequate design. Pilot training can mitigate weak designs in certain situations; thus training should focus on understanding the situation and subsequent risk management - awareness, aided by a suitable alerting system (audio, visual, tactile).