What component of a flight management system allows pilots to update the route during flight?

The flight plan management system is integral to the function of a flight management system as it allows pilots to update the route during flight. This system handles various aspects of the flight plan such as modifications to the course, alterations due to weather changes, and adjustments as directed by air traffic control. It provides the necessary interface for pilots to input new waypoints or change existing routes directly while the aircraft is in operation, ensuring that they can adapt to dynamic flight conditions efficiently.

In contrast, the performance database primarily contains information related to aircraft performance parameters, while the navigation database consists of data pertinent to airways, navigation aids, and fixes that support route navigation but does not directly facilitate real-time updates during flight. The engine monitoring system focuses on the performance and status of the aircraft’s engines rather than navigation and route management. Therefore, the flight plan management system is specifically designed to enable pilots to manage and operationalize flight routes in real time, making it the correct choice in this scenario.