What is the difference between 2 axis autopilot and 3 axis autopilot?
A two-axis autopilot controls an aircraft in the pitch axis as well as roll. A three-axis autopilot adds control in the yaw axis. As aviation technology progressed, the introduction of flight director (FD) systems brought about significant advancements in aircraft automation. AutoPilots provide basic assistance by working on those axis controlled by the pilot’s right hand but can never relieve his left hand on the collective. A 4-axis AutoPilot provides fully hands-off flying capability.