The document discusses a flight management system (FMS), which is a computer system that automates many in-flight tasks. An FMS has several key components, including a control display unit in the cockpit and navigation displays. It contains navigation and performance databases. The FMS allows pilots to enter flight plans, monitors the aircraft's position, calculates efficient routes, and can guide the autopilot. FMS provides advantages like improved navigation, fuel efficiency, reduced workload, and accuracy, but also has disadvantages such as potential for data entry errors, loss of situational awareness, and high cost.