What does it mean if airfields shown in brown on the Enroute Low Altitude - US Charts?

Airfields depicted in brown on the Enroute Low Altitude - US Charts signify that those airfields do not have an available Instrument Approach Procedure (IAP). This means pilots cannot rely on standardized procedures to arrive at these airfields under instrument flight rules, which can be crucial for ensuring safety and operational procedures in reduced visibility conditions.

When planning flights, it's essential for pilots to identify which airfields lack published IAPs as this impacts their ability to navigate safely, especially in adverse weather. Understanding this can assist pilots in making informed decisions about their flight routes, fuel planning, and potential diversion airports.

In differentiating other types of airfields, those with a published IAP would generally be indicated in a different color or style, and temporary closures or non-actuated airfields would also have distinct symbols or annotations not attributed to the brown marking. Therefore, recognizing the significance of color coding on charts aids pilots in navigating the complexities of airspace effectively.