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Comment by arghwhat | Hacker News Reader

Without MCAS, the 737 MAX has a significant pitch up tendency. You can actively trim your way out of this, but it might be a quite notable effort. It is airworthy, but that does not mean it is automatically flying straight and level.

With working MCAS, it should fly roughly like the pre-MAX version, with automatic trim adjustments to hide the significant pitch up tendency that the pre-MAX version with its much smaller engines did not have.

With a buggy MCAS with the failure conditions met, you might have sporadic significant pitch-down.

(... And with a blown load reduction device in the left engine, e.g. from a large bird strike, you'll have the cockpit filled with smoke at fatal toxicity within 39 seconds, but despite being completely avoidable by flicking one switch, and despite also affecting other aircraft with similar devices, the FAA doesn't find it worth any immediate action.)

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All documentation I've seen says that MCAS only activates when the plane has a dangerously high angle of attack, flaps are retracted, and the autopilot is not engaged.

Almost all flights other than by test pilots or air show pilots will never have MCAS do anything unless it receives faulty sensor data, as was the case in the two crashes.

Yes, this is how it should have operated from the beginning. MCAS was flawed when the MAX was first put into operation. Personally, I feel that the MCAS system is "airworthy" now. But that is just MCAS...What is more concerning to me is the quality issues that Boeing has for all aspects of their aircraft. To be clear, this is not specific to the MAX, this is any aircraft that Boeing has pushed out their doors in the past 10 years or so. The foundation for Aviation Safety has a an excellent podcast that goes over the numerous quality issues Boeing has that still exist to this day. https://www.foundationforaviationsafety.org

Boeing used to be a great company that prioritized safety over everything else. (If it ain't Boeing, I ain't going) The "merger" with McDonnell Douglas was the end of that version of Boeing. IMHO, the Boeing 777 was the last great airplane Boeing built. That plane would not be made in the Boeing of today because the initial investment was so high.

Within the normal flight envelope MCAS doesn't activate. MCAS was designed only for the case of high alpha low speed high thrust. Otherwise the max flies very similarly to the NG. The MCAS crashes were only possible because of faulty AOA sensors. There is no inherent defects in the flight characteristics of the MAX.

To be clear, even if MCAS was strictly necessary during all aspects of normal flight, it is not a defect in flight characteristics to require computerized control of flight control surfaces as long as the aircraft is properly designed for it (as opposed to acting with gross neglect for human life). See any fighter jet, or even a regular Airbus with its highly abstract fly-by-wire system.

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