这是我查到的737Max问题解释：

The stall-prevention system (known as MCAS) was poorly designed and implemented. Since it was intended to work in the background, Boeing didn’t brief pilots about the software or train them in simulators. The software didn’t activate when the flaps were down or the autopilot was on.³ And when the MCAS system went haywire, pilots could deactivate it with a switch on the center pedestal of the 737 cockpit. As pilots yoked the airplane upwards, the software automatically pushed the aircraft nose back down. This led to the crash of the two Boeing airplanes.