When is a DISCONTINUITY added to the flight plan?

A DISCONTINUITY is added to the flight plan specifically when a waypoint is inserted and there is no existing DISCONTINUITY below it. This occurs because the flight management system recognizes the need to separate the flight path segments that are not directly connected, indicating a break in the routing.

When a new waypoint is added, if there is already a direct interconnection of waypoints below that point, the system maintains a continuous route. However, if the new waypoint is not logically connected to the previous one in the flight segment, it signals a need to insert a DISCONTINUITY, alerting the pilot to check the routing for potential issues.

Other options describe actions related to flight plan revisions, but they do not involve the automatic insertion of a DISCONTINUITY based on the addition of a waypoint. Therefore, they do not capture the specific condition under which a DISCONTINUITY is created.