What action should be taken if the time before a clearance limit is about to expire?

Issuing a new clearance as the time before a clearance limit is about to expire is essential for maintaining safe and efficient air traffic management. When a clearance limit is approaching its expiration, it is critical to ensure that the aircraft is either given an updated clearance to proceed beyond that point or provided with instructions to safely manage its operations.

In the context of air traffic control, if an aircraft reaches its clearance limit without having received a new clearance, it could lead to potential conflicts with other aircraft or create unsafe situations within crowded airspace. By issuing a new clearance as soon as possible, you effectively allow the aircraft to continue its flight path as planned or redirect it as necessary, ensuring both safety and compliance with air traffic regulations.

Other options may not provide the necessary and immediate action required in this situation. Instructing the pilot to hold indefinitely could lead to confusion or excessive holding time, which is not an ideal solution as it can affect the flow of air traffic. Cancelling the flight plan might unnecessarily disrupt the flight since the aircraft may have options to proceed safely. Contacting the next control center, while an important part of the process, does not directly resolve the immediate issue of the clearance limit expiring and could potentially delay the aircraft's operations.