Boeing Pilots Detected 737 Max Flight Control Glitch 2 Years Before Deadly Crash

New evidence indicates that Boeing pilots knew about "egregious" problems with the 737 Max airplane three years ago, but federal regulators were not told about them.

Investigators say the plane's new flight control system, called MCAS, is at least partially to blame for 737 Max crashes in Indonesia in 2018 and Ethiopia this year that killed 346 people. Acting on data from a single, faulty angle-of-attack sensor, MCAS repeatedly forced both planes into nosedives as the pilots struggled, but failed to regain control.

The pilots in the Lion Air plane that crashed in Indonesia last October did not know MCAS existed, as Boeing did not disclose any information about it in pilot manuals or in training material.