https://www.21stcentech.com/bad-software-boeing-737-max-comm...
"Those 189 who died were victims of Boeing’s redesign of its successful 737 aircraft, all about putting a bigger engine on it and trying to come up with a solution to correct the airplane’s changed aerodynamics. Boeing realized the redesign could lead to potential stalls. MCAS was the answer"
"Software combined with sensors would ensure the airplane would not tilt upward at an unsafe rate. The combination of the two would keep the nose at the precise right angle during all aspects of flight to prevent a potential stall.
Was this, in the end, a good design decision? No based on what occurred to this nearly brand new aircraft"
"Pilots can manually override the MCAS but cannot switch it off without switching off the flight computer. This fact in and of itself proved fatal to Flight 610, its crew, and passengers."
"Since the crash Boeing has sent out a safety warning with a procedure for cutting off MCAS in the event of an AOA sensor malfunction. A description of what a pilot would experience should the MCAS receive false data has been included so that he or she would know when to disengage the flight computer and manually take over flying the plane."
Moreover, bad software effectively working against the pilots, again connected to the stalls, was also the cause of this famous accident some 10 years ago:
https://en.wikipedia.org/wiki/Air_France_Flight_447
"In an article in Vanity Fair, William Langewiesche noted that once the angle of attack was so extreme, the system rejected the data as invalid and temporarily stopped the stall warnings. However, "this led to a perverse reversal that lasted nearly to the impact: each time Bonin happened to lower the nose, rendering the angle of attack marginally less severe, the stall warning sounded again—a negative reinforcement that may have locked him into his pattern of pitching up", which increased the angle of attack and thus prevented the aircraft from getting out of its stall.[25]"