[phire]

MCAS was not a bug. The software behaved excatly as specified.

The issue was the specification itself, which assumed pilots would reliably catch the uncommanded trim down, diagnose it and disable the whole electric trim subsystem within seconds of the problem behavior arising.

That assumption turned out to be massively flawed.

[heavenlyblue]

Then it means that they had to formally verify the specification itself.

It’s not that hard by the way. And they did that, but handwaved the critique - the typical approach of “my guts are probably more correct than maths”.

[nicoburns]

Formal verificatiom can't tell you if you're assumptions are off. It can only work from those assumptions.

[jacquesm]

Your comment implicitly - and probably unintentionally - appears to assign part of the blame to the pilots, which I think is a very bad thing to do in this particular case.

[phire]

Not my intention at all.

Even if my comment implies that there might be pilot error, pilot error doesn't mean pilot blame.

In this case, I'm very much of the opinion that the blame either belongs with the official Boeing training program, which didn't correctly train any 737 pilots to correctly handle this scenario.

Or the blame belongs to the design specification that relied on the assumption pilots would be able to correctly handle this scenario with out even testing that assumption. Or potentially both.

Even if say 10% of pilots could fluke into handling this scenario without the correct training, doesn't mean the other 90% are to blame for not flukking into a correct solution.

[shreyansj]

I think specification here refers to the type specification of the aircraft. It's not putting the burden on the pilots but rather on the lack of pilot training due to Boeing and airlines not wanting to bear the cost of training pilots to a new aircraft type.

[bsder]

> airlines not wanting to bear the cost of training pilots to a new aircraft type.

This is a perfectly reasonable request by the airlines. Some airlines rely on the operational efficiency of a single aircraft type. It lets them interchange parts and people and not have to worry that the wrong airplane is in the wrong spot.

What is NOT reasonable was Boeing providing an aircraft that actually had MAJOR differences yet claiming it was the same.

And what makes it particularly stupid is no airline that relies on a single airplane type is going to switch from Boeing to Airbus because they would have to migrate their entire fleet en masse. So Boeing had plenty of time to certify the 737 MAX airframe properly.

[redis_mlc]

Incorrect. The Indonesian investigators shared blame between Boeing, mechanics and pilots. (Their NTSB is US-trained.)

[redis_mlc]

"Indonesian investigators have determined that design and oversight lapses played a central role in the fatal crash of a Boeing 737 MAX jet in October, according to people familiar with the matter, in what is expected to be the first formal government finding of fault.

The draft conclusions, these people said, also identify a string of pilot errors and maintenance mistakes as causal factors in the fatal plunge of the Boeing Co. plane into the Java Sea, echoing a preliminary report from Indonesia last year."

https://www.wsj.com/articles/indonesia-to-fault-737-max-desi...