What is required of the flight crew when a filed flight plan has been amended within 30 minutes of departure?

When a filed flight plan has been amended within 30 minutes of departure, the flight crew is required to notify Air Traffic Control (ATC) of the two flight plans on file. This notification is crucial as it ensures that ATC has the most current information regarding the flight's intentions, improving situational awareness and safety. ATC needs to be aware of both the original and amended flight plans to coordinate traffic effectively and avoid potential conflicts with other flights. By communicating both plans, the flight crew helps maintain an organized airspace and ensures compliance with regulations. This practice enhances safety and efficiency in the overall air traffic management system.

The other options do not adequately address the needs of communication with ATC in light of an amendment to a flight plan. For instance, canceling the flight plan or only following the original plan could lead to misunderstandings and potential safety risks.