What does the yellow arc on the airspeed indicator signify?

The yellow arc on the airspeed indicator signifies the caution range for maneuvers. This indicates that the aircraft should be operated with caution within this speed range, as flying in this area increases the risk of encountering adverse situations, such as reduced control effectiveness or potential stall conditions. It serves as a warning to pilots that while flight is possible within this range, it is not advisable to conduct maneuvers that could lead to risks associated with poor aircraft handling or stability.

In contrast, the normal operating range is typically represented by the green arc, showing speeds considered safe for regular flight operations. The maximum speed would usually be indicated by the red radial line at the top of the airspeed indicator, and stall warnings are generally indicated through features in the aircraft's design rather than a specific range on the airspeed indicator. Understanding these markings helps pilots maintain safe operational practices while flying.