B-737 Analysis of What Happened

Reading an article or two and listening to some descriptions of why the Boeing 737 MAX crashes occurred has been enlightening and somewhat disheartening. It appears that budget cuts by the government kept the FAA from doing sufficient study of the new airplane configuration.

Here's an article from Quartz which tells about the airplane and problems:
https://qz.com/1575509/what-went-wrong-with-the-boeing-737-max-8/

Following is a quote from the article which I found interesting:

/quote

Black box data from the Lion Air crash shows that readings from the two angle-of-attack sensors differed by 20 degrees even while the plane was taxiing on the runway, indicating that the instruments were faulty from the start.

Warning lights optional

Boeing designed a warning light that would alert pilots when the sensors measuring their plane's angle of attack differed widely, which would give notify them of a faulty MCAS activation.

The manufacturer does not install the warning light as a standard feature on the 737 Max 8. Airlines have to pay extra for it.

/end-quote

So, the two sensors were working differently. Were they fixed? Were they checked on all the other B-737s?

Why was a warning light about the sensor ONLY optional equipment?

Why, after the first crash was this not reviewed? A regular idea in aviation is that if you've done something and a problem immediately arises it may be related to what you did and you should consider undoing that thing. They put in a new engine with MCAS and sensors and suddenly the new airplane had this problem. Add two and two and perhaps they should have considered reviewing whether to undo what they had just done.

Another quote:

/quote

The safety analysis Boeing sent to the FAA reported that the MCAS could only move the plane's horizontal tail 0.6 degrees (out of a physical maximum of a little less than five degrees). But during later flight tests, Boeing discovered that 0.6 degrees of movement wasn't enough to avert a high speed stall, the Seattle Times reported. Boeing eventually increased the limit to 2.5 degrees.

Despite quadrupling the amount that the MCAS could move the plane's tail, Boeing never updated the documents it sent to the FAA. FAA engineers only found out about the change after the Lion Air crash, when Boeing sent a notice to airlines explaining how the system worked.

/end-quote

Apparently the typical corporate money-saving mentality sank in and they decided to lie to the government. I hope the penalty for that is serious.

They have another computer-takes-control issue in that when the pilot would pull back on the yoke to raise the airplane nose, that action would reset the sensor and the nose-down pitch problem would or could repeat. This appears to have happened in both the crashes. The pilot could fight the nose-down pitch for a brief time, but the machine would just reset and do it again unless the pilot knew how to completely disconnect the MCAS system. Were the pilots trained and shown how to disconnect it?

Machines using computers are powerful and they're being used quite a lot in our world. The Internet vulnerability to hackers is one which shows that security and safety of such systems isn't always built-in or understood. The FAA and commercial airlines have reduced accidents, but with this one new cost-saving measure Boeing gave us one more problem to solve and clear evidence we aren't yet very good at producing safe machines on a first try.