What type of airports are indicated by brown colors on an IFR chart?

The option indicating that airports with brown colors on an IFR chart are those with no Instrument Approach Procedures (IAP) is based on the standardized symbology used in aviation mapping. On IFR charts, airports depicted in brown signify that these facilities do not have established IAPs, which are essential for pilots to safely approach and land in low visibility conditions using instruments.

The reason for this distinction is to help pilots quickly identify which airports may have limitations in terms of instrument approaches. This information is crucial for flight planning, especially when considering alternate airports or assessing capabilities in adverse weather conditions.

Other options relate to different classifications of airspace and airport operations. Airports with IAPs are depicted using different colors or symbols, VFR use only airports would be indicated similarly to those without IAPs but often have additional markings or notations that identify their specific operational use, and military-controlled airports have unique designators that distinguish them from civilian airports. Understanding these symbols allows pilots to make informed decisions based on the operational capabilities of various airports they may encounter.