737 Max autopilot inquiry

If I remember correctly there is a third autopilot that is turned on automatically when the other two autopilots are engaged by the pilot. It's was not easy to find reliable information on this though.

The autopilot design can be fail passive or fail operational. That means during approach when both autopilots are engaged at the same time if a malfunction is detected the system either disengages completely and you need to go around or land manually (fail passive) or it remains engaged and operational and you can continue with the automatic landing (fail operational).

Both versions exist in the real world, our 737 NG has a fail passive design with autoland but without rollout capabilities, meaning it disconnects after touching down, and the 737 MAX has a fail operational autopilot with rollout capabilities, meaning it can land on its own until complete stop.

Thanks, I updated it.