Airlines lobbying FAA to have only one pilot in the cockpit

No, it isn't.

> The way I'm reading it

What it says is to restore trim to normal and then turn it off.

> not fully grasping the danger of leaving that switch on normal

Uncommanded stabilizer trim movement is a severe problem which is why what to do about it is a "memory item", meaning you don't have time to read the checklist. All pilots should know that runaway trim is a critical danger.

> out of nowhere - entering an uncontrollable nosedive if the pilots don't properly respond within seconds

There's enough time to respond. All three crews correctly restored normal trim immediately.

> I still have trouble blaming the pilots because

I give the pilots some of the responsibility, because they had all the information needed to counter the problem. The rest goes to Boeing for a bad MCAS design. It's a pilot's job to read, understand, and remember Emergency Airworthiness Directives. If that's unreasonable for them, they need to turn in their wings and drive an Uber.

I find no fault for the pilots of the Alaska crash where the stabilizer trim jammed. There were no instructions on how to deal with that, and they were in contact with the maintenance chief who had no clue, either. The pilots kept trying to break the jam loose, doing things like engaging both trim motors to apply more torque. The result was the jackscrew nut stripped the threads, and then it slid to hard over, then broke the end of the jackscrew off, and it was game over.

Now me, as an engineer who knows how that system works, I would have advised them to leave it alone, reduce airspeed to reduce the loads on it, and land ASAP. The jackscrew motors are way too powerful to let them grind away at it. Also, when it did move, it let off a very loud screech indicating that something awful was happening.

But they weren't engineers or mechanics. They made a mistake, but it was reasonable considering what they knew. They did the best they could.

Interesting how I assume HN is capable of a rational conversation around this, but when the exact same premise is raised around self driving cars, all rationality flies out the window

However we design systems and procedures such that suboptimal usually doesn't mean fatal, and in those specific instances where it would, we train humans so they perform adequately.

If humans were so great, we wouldn't need a lot of the technology in modern aircraft. It's mostly there because humans suck. Taking work away from the meatbags, putting in safeguards, and designing with the human element in mind, produces more desirable outcomes.

And it's not like this crew had the wrong ideas. They attempted all the right things, but execution was lacking and sadly the situation had no room for error:

1. Did use cut out, but left it on normal for a few crucial seconds without any manual input, allowing the computer to mess everything up again.

2. Did try to fix trim before cut out, but only got it halfway there to the point where they could at least achieve level flight and a slight climb. Tried to trim the rest of the way manually, but that didn't work.

> There's enough time to respond.

Disregarding that the situation could have been avoided, the second time this crew didn't have time to react anymore. It took only 3.5s from the automatic nose down engaging to descending at -5,000 ft/min, pitching -8° down and quickly increasing to -40°, despite the pilots pulling on their sticks full force. They had maybe a second or two to nip it in the bud, then had twenty seconds left to somehow arrest the rapid descent of an aircraft that is trimmed precisely the wrong way with the horizon in a place you don't ever want to see it in a commercial airliner. I don't think it was physically possible?

It's not hard imagining situations where an aircraft doing something like that within 3.5s out of nowhere would be disastrous. There certainly wouldn't be time to respond. This crew was warned by earlier misbehavior, so the situation was theoretically avoidable, but there was little room for error and so we should be glad for all the times something didn't happen.

> All three crews correctly restored normal trim immediately.

Are you counting this crew? I don't think they had normal trim at any point once the incident started. They were trying to get there.

It used to be 'level the wings, pull the nose.' The issue is even expert ATPs often perform the wrong action initially, making the problem worse.

This is not remotely true. Two humans can easily land in dense fog with instruments alone. If you can't then you shouldn't be flying a plane especially not one with passengers. To suggest otherwise is absurd.