When is the departure airport included in a clearance?

The inclusion of the departure airport in a clearance primarily occurs when the clearance is relayed through a non-control facility. This is significant because in such cases, providing the departure airport ensures clarity and helps prevent misunderstandings regarding the route and the intentions of the flight. Additionally, it offers the pilot crucial situational awareness when transitioning from non-controlled to controlled airspace.

When the departure airport is provided in these situations, it helps maintain safety and continuity in communication, especially when pilots may be unfamiliar with the terminal or surrounding airspace. Meanwhile, other factors like radar coverage, pilots requesting additional information, or weather conditions being favorable do not specifically dictate the inclusion of the departure airport in the standard clearance process. Rather, these factors might affect other operational aspects, but they do not have a direct influence on whether the departure airport information is included in clearances.