Originally Posted by
jdawg
Why would you react to a trim runaway if the problem did not present itself that way? You're confusing us.
This touches on another training issue that I have previously commented on, that being the overly structured and highly procedural approach that has crept into pilot training. And I will again remind everyone that every manufacturer will clearly state that they cannot possibly devise a checklist for every situation, and sound judgement is always called for when evaluating an aircraft malfunction.
For example, not all engine malfunctions conform to the typical failures seen in the sim. Back in my 727 days, I once had an engine that was producing some odd readings (mainly a mismatch between EPR and RPM's with a very slight amount of adverse yaw). The engine was producing thrust, none of the readings were out of limits, and none of the checklists addressed what we were seeing. Yet something was "off." We decided to secure the engine and land. Upon inspection after landing, maintenance determined that a bleed duct had failed and would have likely resulted in further damage if we had not shut down the engine. In this case, if a crew had been looking for some kind of specific written guidance on how to handle this malfunction, they would have come up empty.
You are absolutely correct that a MCAS malfunction does not look like a "classic" runaway stab trim problem particularly in that it lacks that "continuous" aspect referred to in the QRH. However, from the perspective that this malfunction resulted in uncommanded and undesired stab trim inputs, then the Runaway Stab Trim NNC was a suitable tool by which to address it. That thought process, however, required something of a "big picture" perspective that I believe is not adequately taught at many airlines today.