Engines had to be mounted higher up on the wing so as not to scrape the ground. Note that said engines were not designed to fit the 737

• Engines had to be mounted higher up on the wing so as not to scrape the ground. Note that said engines were not designed to fit the 737
• It changed the plane stability in a way that it could pitch up in an irrecoverable way (plane stalls, nose can’t be pitched down, more power makes things worse)
• Instead of fixing the problem for real or re-designing the plane, boeing added a software patch: MCAS
• It’s supposed to pitch the plane nose down if the angle of attack is detected to be too high.
• Questionable fix, but it could have worked, except...

737 Max