Computers overriding human instructions have also caused crashes.
http://en.wikipedia.org/wiki/Scandinavian_Airlines_Flight_75... -- engines ingested ice and started surging. Pilots commanded reduced power, but the Automatic Thrust Restoration system no one told them was there countered that move, leading to a double engine failure and a crash landing.
http://en.wikipedia.org/wiki/Scandinavian_Airlines_Flight_75... -- engines ingested ice and started surging. Pilots commanded reduced power, but the Automatic Thrust Restoration system no one told them was there countered that move, leading to a double engine failure and a crash landing.
http://en.wikipedia.org/wiki/China_Airlines_Flight_140 -- pilot accidentally flipped the takeoff/go-around switch, leading the autopilot to counter the crew's attempt to recover, causing a stall and crash.