What does the "yellow arc" on the airspeed indicator indicate?

The yellow arc on the airspeed indicator represents the caution range where pilots are advised to exercise caution. This range indicates airspeeds that are not safe for normal operations but may still be usable in certain situations if the pilot is aware of the limitations and operates within that caution range.

When flying in this range, the aircraft may be nearing its performance limits, such as approaching stall or exceeding structural limits. It's crucial for pilots to recognize this area as it implies potential risks associated with performance during maneuvers. Understanding the meaning behind the yellow arc aids pilots in making informed decisions and maintaining safety during flight operations.

The normal operating range, represented by the green arc, is where the aircraft is typically flown safely and efficiently. The stall warning range is indicated by another section of the indicator, typically represented by the lower limits approaching the stall speed, while the maximum level flight speed would be indicated by the red radial line, defining the absolute maximum airspeed limit for safe flight. Recognizing these distinct arcs helps pilots ensure they operate the aircraft within safe parameters.