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Comment by formerly_proven | Hacker News Reader

> It shows me how hard it is to notice the absence of something. I was not aware that no US airline had crashed in the past 15 years. And I didn’t realize what an incredible safety record this represents, given how many people are boarding flights every day.

Pure luck though with the whole Boeing thing. There's no particular reason why those 350-odd dead in two crashes couldn't have happened to an US airline. (It would've been better for aviation safety if it did).

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I think pilot training is almost certainly a factor. Technically, Boeing are correct that a fully trained and competent 737 pilot should have been able to execute the runaway trim procedure (which is a memory item) and recover the aircraft without incident. However, the fact that two sets of pilots failed to do this in quick succession showed that pilot training could not be relied on to this extent in practice. On average, pilot training ought to be better in the US than in many (not all) other countries.

> There's no particular reason why those 350-odd dead in two crashes couldn't have happened to an US airline.

True, but in practice, not so

American pilots had two things for them here:

1) more aware of maintenance needs of speed sensors (and probably better SOPs as well regarding disagreeing sensors) and

2) more experience with flying manually (on older 737s even) and acting correctly if MCAS went haywire

Isn't a big part of the issue for the first incident that pilots didn't know MCAS even existed?

Yes, but there existed a procedure for "Runaway Trim"

(This showed up in Google but I think the 1st answer, rather than OP is right here https://news.ycombinator.com/item?id=19416050 - of course now we have the FAA report)

It's been a while and I don't remember the details, but if I remember correctly US airlines' aircraft were equipped with dual airspeed sensors, or some other sensor. Or both sensors were used as inputs to the MCAS.

They always had two, but the disagree alert was the extra. It's still mindblowing when you read again the details, and realize nobody went to prison...

https://en.wikipedia.org/wiki/Maneuvering_Characteristics_Au...

Not only did no one go to prison but Boeing got an incredibly generous deferred prosecution deal that said that if they didn't break the law for two years the government would drop the charges and then Boeing couldn't even do that and then plead guilty. But they only get a pretty tiny $243.6 million fine

I don't think the disagree alert would have helped. Pilots weren't trained on MCAS, so they wouldn't have thought "oh, the AoA sensors disagree, so I'd better switch to manual trim".

> Pilots weren't trained on MCAS

And it wasn't referenced anywhere other than the glossary which explained what the abbreviation meant, so they had no chance.

Both MCAS crashes would have been avoided if the crew correctly executed the memory-item runaway stab trim checklist. (The second crew almost saved it by first correctly executing that checklist, then reversing that corrective action while trying to recover, after which point the flight was lost.)

That’s what Boeing was counting on (and was terribly wrong in retrospect).

Indeed. I made the same point here: https://news.ycombinator.com/item?id=42295005

> Pure luck though with the whole Boeing thing. There's no particular reason why those 350-odd dead in two crashes couldn't have happened to an US airline. (It would've been better for aviation safety if it did).

And also the door blowout, in which Boeing employees forgot to put bolts back in, because they sidestepped the system, wasn't a crash only thanks to pure luck. The door could have easily taken parts of the tail with it, potentially severing horizontal/vertical stabilisers, hydraulics, etc. It could have been a very deadly affair.

Certainly not just down to luck across the industry as a whole though. That particular type was exempt from a bunch of regulations, written in blood, that all the other popular types comply with.

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