Lot’s of very interesting and detailed discussion here. I’ve learned quite a bit about electric motors and their control circuits, so thanks. I should point out, however, that all this is far, far above the level of detail that would ever be included in the FCOM.
Now back to the elephant in the room. All of us are basically amateurs when it comes to accident investigations. Many of us like to know how things work, or should work, and enjoy puzzling things out from the limited information that is available. Perhaps some of us just like a good mystery. Perhaps some don’t have the patience to wait for the investigative process to run its course or are uncomfortable with what is perceived as an information void. I absolutely get the psychology at work.
While I consider myself fairly knowledgeable about the 737 and it’s operations, I will acknowledge that the information and resources I (or anyone else here) possess is absolutely dwarfed by those available to the collective body of professional accident investigators, multiple certificate authorities representing dozens of nations, subject matter experts, and other interested parties such as the aerospace-centric media (i.e. Aviation Week and the like) and the massive army of tort lawyers lining up to sue Boeing.
Is anyone here seriously suggesting that it has not occurred to any of these parties that they should investigate the Main Electric Trim system to see if there were any issues? Please speak up, because I would really like to hear your thinking here.
In the past couple of months, we have heard a litany of items that various certificate authorities want to see addressed before the MAX is cleared to fly. Conspicuously absent is any mention of the Main Electric Trim system. No suggestion of failures, stalls, overheats, or anything else. No one is asking for any redesign or replacement of switches, relays, wires, or motors. If this was still early in the investigation, sure, absolutely valid questions have been raised. And all those questions have been found wanting of actual hard, verifiable evidence to back them up.
So really, folks, why the continued obsession with this system? No party who actually has all the data, resources, and experts is saying anything about it. Do you really think you are more knowledgeable than the collective body of all these very smart people? There is far too much grasping for straws that simply aren’t there.
Time to move on.