Centaurus,
A sound and well reasoned position #1.
Questions for clarification; does the yo-yo manoeuvre involve reducing the manual control force to, or only towards zero; not withstanding the likely hood of a crew doing this at low altitude, more-so if they had not been specifically trained for the event.
Is this problem similarly described as a ‘jack stall’ in other aircraft.
Do these versions of the 737 have an automatic cross-cockpit control force disconnect to alleviate a jammed control; thus with a trim problem, if one pilot pulls hard and the other doesn’t, then what …
If the pitch control system is ‘split’, would an ‘inactive’ elevator provide sufficient relaxation on the tail forces to enable manual trim input.
Conversely can a single elevator generate sufficient nose-up change to allow a load alleviating manoeuvre.
Does the 737 Max FCTM consider this situation - different aerodynamics, but presumably a similar physical control mechanism and air loads.