What is indicated by blue markings on Sectional Aeronautical Charts?

• A. Major highways
• B. Airports with control towers in Class B and C airspace
• C. Uncontrolled airfields
• D. Temporary flight restrictions

Answer: (B)

Blue markings on Sectional Aeronautical Charts signify airports that have control towers and are located within Class B and C airspace. This is an important feature for pilots as it helps them identify areas that require adherence to specific air traffic control procedures, thereby enhancing flight safety and efficiency in busy airspace regions. Class B airspace, for example, typically surrounds the busiest airports and requires pilots to establish two-way communication with Air Traffic Control before entering, while Class C airspace surrounds airports with a moderate level of traffic.

The color coding of aeronautical charts is designed to provide crucial information quickly and effectively. The blue markings indicate that the airport has a control tower, which is essential for managing the flow of air traffic, especially in environments where numerous aircraft are operating in proximity.

In contrast, other options do not accurately reflect the significance of blue markings. Major highways, uncontrolled airfields, and temporary flight restrictions are represented by different symbols and colors on sectional charts, indicating that pilots should refer to the legend or key for accurate navigation information.