Long flights would exhaust any crew without help. The autopilot holds heading, altitude, and speed, freeing pilots to manage navigation, communication, and systems. It does not replace them, though the line gets blurry on modern aircraft.

Basic autopilots maintain one axis at a time. Full flight management systems fly entire routes from takeoff to landing, following programmed waypoints and adjusting for winds. The crew monitors and intervenes when needed.

Common autopilot modes

• Heading hold
• Altitude hold and vertical speed
• Navigation tracking of a route
• Approach mode for landing

Automation introduces its own risks. Pilots who rely too heavily can lose manual flying skills, and confusing mode changes have contributed to accidents. Training now emphasizes monitoring automation as carefully as flying manually.