Originally Posted by
Lake1952
Can the MAX be recertified without solving the issues related to the manual trim system? And how is the manual trim system handled on older versions?
Since the days of the 707, one of the issues with this trim system is that it is very difficult to operate the manual trim wheel from an excessive out-of-trim condition. The answer then is to not let this aircraft get grossly out of trim which means that flight crews need to keep the stab trim state, and any motions of the trim wheel, very much in their regular cross check, and respond promptly to any undesired trim inputs.
Ironically, before the MAX the 737 stab trim system had become very reliable and significant problems were very rare. This level of reliability generated a great deal of complacency among both crews and airlines which then led to a lack of regular training with and awareness of potential runaway stab scenarios. This training deficiency can potentially contribute to problems with recognition and delayed crew response.