Which airspace class is typically charted with dashed blue lines?

The airspace class that is charted with dashed blue lines is Class D airspace. Class D airspace typically exists around airports with an operational control tower and is designated to provide a safe and organized environment for aircraft operating in the vicinity of those airports. The dashed blue lines on aeronautical charts indicate the horizontal boundaries of this airspace class.

Class D airspace extends from the surface to a specified upper altitude, which is usually 2,500 feet above ground level, and is depicted on sectional charts to inform pilots of where communication with the tower is required. The designation of airspace with dashed blue lines helps pilots easily recognize the boundaries of this controlled airspace, where air traffic control services are provided.

Other classes of airspace have different charting indicators. For instance, Class C airspace is represented with solid magenta lines, Class E has both dashed and solid lines depending on the specific configuration or height (like at airports or in transition areas), and Class G is uncontrolled airspace and is not indicated on sectional charts.