What is a primary reason for pilots to have knowledge of alternate airports during a flight?

Pilots are required to have knowledge of alternate airports primarily to ensure they are prepared for emergencies. In the event of sudden changes in weather, mechanical issues, or other unforeseen circumstances that prevent landing at the intended airport, an alternate airport serves as a backup landing option. This preparedness enhances safety by providing pilots with alternative options to ensure they can safely land their aircraft if necessary.

While planning for potential unscheduled stops is a reasonable consideration and may factor into flight planning, the emphasis on emergency preparedness underscores a critical aspect of the flight operation. Understanding alternate airports is fundamental to a pilot's situational awareness and risk management during a flight, thereby reinforcing the importance of knowing these alternatives in case of urgent circumstances that may arise.