What does a yellow circle with an "R" in brackets indicate on a sectional chart?

A yellow circle with an "R" in brackets on a sectional chart signifies a restricted area. This type of symbol is specifically designed to alert pilots to areas where flight is restricted due to various reasons, such as security or safety concerns. These areas can be off-limits to general aviation and require pilots to be aware of the boundaries and regulations associated with them. Pilots must reference current sectional charts, as restricted areas may have specific altitude limits or operational hours that dictate when it is permissible to fly through or around them.

Understanding this symbol is critical for safe navigation and compliance with Federal Aviation Administration (FAA) regulations, reinforcing the need for pilots to be vigilant about the airspace classifications and restrictions that may affect their flight paths.