My summary (not that I necessarily agree with the the explanation):
A new larger engine was designed to be put on the old Boeing 737 plane design. It was too large to be installed below the wing’s surface of the Boeing 737 Max 8, but Boeing moved it up higher and part of it was above the wing surface. This sometimes caused the nose of the plan to point too high at takeoff and risked stalling out the plane.
To compensate, Boeing installed a software system to push the nose down to prevent it from stalling out by rising too high. It was called the Maneuvering Characteristics Augmentation System or MCAS.
Because the basic 737 plane itself was not changed all that much, Boeing did not highlight the new MCAS and pilots only got two-hour iPad training on the new plane before entering the cockpit the first time. And the training material didn’t mentioned the MCAS software.
On October 29, 2018 Lion Air flight 610 took off from Jakarta Indonesia, and had trouble with the nose frequently turning down — this was presumably caused by the MCAS software. The pilots could not figure out what was causing it and how to stop it. The plane was getting incorrect sensor data that caused this and it crashed 12 minutes after take off.
In the case of Ethiopian Airlines Flight 302 on March 10. 2019, after the flight took off the pilots disabled the MCAS system because it was causing the nose of the plane to tilt down. But it was too late. It crashed.
The narrator claims Boeing was so eager to beat Airbus they were negligent in design and training on the new engine and MCAS software and the FAA was negligent in approving the design. Airbus had built a larger engine that was more fuel efficient. But because its Airbus A320 model was higher off the ground than Boeing’s 737, there was room on the Airbus for the larger engine to hang under neat the wing as its smaller engine was able to do on the old model.
Pratt & Whitney makes the GTF-design series engines.
They are more fuel-efficient, much quieter, and have lower levels of toxic emissions than the GE engines on the Max.