What is indicated if an aircraft will not enter an ATA due to its flight route?

When an aircraft cannot enter an Assigned Traffic Area (ATA) due to its flight route, it is important to report this situation to the radar controller. This action is necessary because the radar controller needs to be aware of any deviations from standard procedures to ensure safe airspace management. By reporting the issue, the controller can make informed decisions about the flight's trajectory, possibly adjust other aircraft in the area, and maintain overall safety and efficiency in air traffic operations. This communication is critical for coordination and to avoid potential conflicts with other flights, ensuring that the airspace remains safe for all aircraft involved.