Originally Posted by
737 Driver
During our trip, we discussed a number of issues that had come out of the recent MAX crashes. During this conversation, he confessed that before these accidents, he did not even know the stab trim wheel had a stowable handle and had never been trained in its use. Think about that for a moment. Also consider that a freshly-minted 737 Captain would have received the exact same training.
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He (fleet manager) added a telling remark, however, that stab trim malfunctions had never been a statistically significant problem at our airline, implying of course that the training events our pilots are exposed to constantly needed to be justified by historical data.
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This supports my impression that the manual trim system as originally designed has been continually degraded both by training and physical changes such as smaller wheel and removal of separate auto only cutout option.
At the same time the sources of runaway trim have increased as more automatic systems use the trim, NG sts and other? , MAX + mcas and other?.
Can not help but think that the safety analysis used a faulty evaluation of manual trim
system, mechanical and pilot training, when assessing MCAS impact, falling back on grandfathered original analysis of effectiveness/useability.