What must a pilot do if they encounter a clearance limit?

When a pilot encounters a clearance limit, the appropriate action is to hold at the last assigned waypoint or fix until they receive further instructions from air traffic control. This is important because a clearance limit indicates that the pilot is not authorized to proceed beyond that point without additional guidance. Holding ensures that the aircraft remains safely in controlled airspace while awaiting further direction.

Proceeding to the next waypoint immediately could lead to unauthorized actions as it bypasses the necessary communication with air traffic control. Contacting air traffic control for an alternate route might not be necessary unless instructed, and continuing to fly towards the destination without adhering to the clearance limit would be unsafe and contrary to regulations. Therefore, holding at the clearance limit is the crucial step that maintains safety and compliance with air traffic procedures.