How is the horizontal limit of Class D airspace represented on a Sectional Chart?

In sectional charts, the horizontal limit of Class D airspace is illustrated using dashed blue lines. This representation helps pilots quickly identify areas where the Class D airspace operates, usually around airports with an operational control tower. The use of blue lines for Class D airspace contrasts with other airspace designations, such as Class C or Class B, which have different line styles and colors. Recognizing these visual cues on sectional charts is crucial for pilots to ensure compliance with airspace regulations and to maintain safe operations in the vicinity of airports. Understanding the different representations of airspace on charts is an essential part of navigating the National Airspace System effectively.