What must a pilot do if they do not take off by the clearance void time?

When a pilot does not take off by the clearance void time, the appropriate action is to notify Air Traffic Control (ATC) within 30 minutes. This requirement is in place to ensure the safety and efficiency of air traffic operations. If the pilot fails to take off within the timeframe specified in the clearance, it indicates that the flight has not commenced as planned. By notifying ATC, the pilot helps to keep the airspace management process smooth and allows controllers to update their records and potentially reallocate resources.

This communication is crucial because if ATC isn’t informed, they may assume the aircraft is still en route or may open the slot for another aircraft, leading to potential miscommunication and safety issues. Therefore, prompt notification within 30 minutes aids in maintaining clear and precise coordination in busy airspace scenarios, ensuring that air traffic is managed effectively and safely.