[bkdbkd]

The turn off the MCAS system button on the 737 Max the pilots were using, does _not_ in fact turn off the MCAS system. It is a "Pause the MCAS system button" Even worse, After a few moments, the MCAS system reactivates and then adds even more down trim. So pressing the button, not only does not turn off the system, actually triggers the plane to make the situation worse by adding more down trim.

When the FAA certified the 737 Max the MCAS Software was able to move the horizontal tail a max of 0.6 degrees. (out of a total of 5 degrees) The software flying on those planes was in fact able to move the horizontal tail 4.17 times that amount: 2.5 degrees. They never told anyone this changed. The system went from being able to control 12% of the tail range to 50% of its range.

Those pilots were pulling up on the nose of the aircraft with their feet pressed against the controls. Directing the aircraft with clear intent and skill. The 737's automation had unbeknownst to them and with their knowledge of the aircraft - un-overridable, tilted the horizontal tail into a position that would, under any operating condition direct the nose of the craft into the ground.

[jki275]

They pulled the breakers for MCAS. That was the correct action. The problem was that then they turned them back on because they flew the plane into a situation where they could not trim it anymore by hand. When they turned the breakers for MCAS back on, it flew the plane into the ground.