Which color is generally used to indicate cautionary information on instrument gauges?

The color that is generally used to indicate cautionary information on instrument gauges is yellow. This color is effective for alerting pilots to conditions that require attention but are not immediate emergencies. For instance, when an instrument gauge presents yellow, it could indicate that certain parameters are approaching their limits or that a system is under certain levels of stress.

This visual cue allows pilots to quickly assess the operational status of the aircraft and take action before a situation worsens. Other colors like red typically denote serious hazards or critical issues that demand immediate attention, while green is used for normal operating conditions, and blue often indicates that a system is engaged or selected. Thus, yellow serves a specific purpose in aviation safety by standing out as a color that signifies caution, guiding pilots effectively in managing their aircraft's performance.