How will the flight plan be affected if it is not opened by the designated time?

If a flight plan is not opened by the designated time, it will be automatically canceled by the Flight Service Station (FSS) after one hour. This procedure is essential for safety and resource management, as open flight plans require monitoring and can impact search and rescue operations if the pilot becomes overdue.

In this context, it's important to understand that flight plans are a means of ensuring that both pilots and FSS are aware of one another's activities. If a pilot does not open the flight plan within the specified time frame, it indicates that the planned flight may not be occurring as intended, leading to an automatic cancellation process to prevent unnecessary search efforts.

Other options suggest actions like keeping the flight plan open indefinitely, notifying the pilot by phone, or sending a cancellation via email, which do not align with standard operating procedures. The one-hour cancellation rule is a critical aspect of maintaining efficiency and safety in air traffic management.