[cstross]

Boeing merged with McDonnell Douglas in 1997.

McD-D had for a couple of decades prioritized military/defense/space contracts over civil aviation and had turned into a finely tuned machine for milking government cost-plus contracts. They also had a bad case of Jack Welch management disease.

Over the years after the merger, Boeing's traditional management was largely replaced by the imported profits-over-everything culture of McDonnell-Douglas. This is, to put it mildly, not your grandparents' Boeing any more.

Because the design life of an airliner is on the order of 30 years, it took years to decades for the cultural change to become visible on the outside, but the 737 MAX MCAS debacle is symptomatic of the change in priorities to focus on hitting sales targets over engineering and QA, with lethal results.

(The simple fact that they had to add MCAS to compensate for changed handling characteristics in the 737 MAX isn't damning on its own, although it was a marketing-driven decision: really, at 50+ years old, it's past time Boeing designed a clean-sheet 737 replacement to compete with the A320 family. But then Boeing didn't see fit to mention MCAS in the pilots' handbook. An MCAS failure can cause a 737 MAX to become unflyable if it fails and the pilots don't understand what's going on, and that has led to two fatal crashes. And the 737 MAX MCAS is controlled by a single sensor, introducing a single point of failure. A dual sensor option is available to customers, but at extra cost -- and this is unforgivable. And now we learn that new-Boeing's institutional response is to demand exemption from FAA oversight? It's not looking good!)

[PaulHoule]

The thing is all the other major airliners today (even made in Brazil!) have fly-by-wire and a "flight envelope protection" system which is like MCAS but more comprehensive, better thought through, documented, etc. That is, pilots are trained in the system and a huge amount of effort went into thinking through how the system should behave when it is in a degraded condition and some parts of the system (like those sensors) aren't functioning properly.

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

[masklinn]

Well yes, the problems of MCAS are not that it exists (although its implementation was definitely debatable, notably the use of a single AoA sensor, and AoA sensor warnings being optional), having FBW and flight envelope correction is not an issue in and of itself.

The issues of MCAS was that it was added specifically to hide type behavioural differences with previous 737s with the specific goal of keeping the type, and thus the entire purpose of MCAS precluded training pilots on its behaviour and edge cases.

[mcv]

Basically it was to maintain a lie. The illusion that it was the same plane as older models. They needed it in order to pretend there was no change, but that also meant they couldn't teach pilots about this new system interfering with the plane's flight behaviour.