The autopilot isn't HAL, or anything like it. Autopilots execute a series of instructions which are programmed at the start of any flight and modified as necessary en route.
Essentially, the autopilot follows a script while using the instruments to maintain the airspeed, altitude, and climb/descent rate that is programmed. They also entrust it with turning off the seatbelt lights at 10,000ft.
This is the easiest part of flying and the most mundane. The auto-pilot accomplishes this through something very similar to a bunch of PID controllers connected to the most basic sensors.
That may not prevent it from being called a robot... but it's really the reverse scenario of what you present. The robot takes care of a relatively trivial task while the pilots take care of "everything else" (flight rules, fuel, traffic, coordination, navigation, etc etc).