Lion Air Flight 610Monday October 29, 2018
The 737 MAX contains a new feature, Maneuvering Characteristics Augmentation System (MCAS), that automatically trims nose down when it the system senses an impending stall. A faulty Angle of Attack (AoA) sensor led the system to believe the plane would stall imminently, so it pitched the aircraft down.
The pilots were unaware of this new feature as Boeing had not included it in their differences training for upgrading pilots certification to the 737 MAX. This exacerbated the issue because the pilots did not realize that the MCAS behavior could be disabled, and instead they continually attempted to fight the nose down commands until the plane crashed into the Java Sea.