What is indicated when the prop RPM gauge enters the Yellow Display Caution Range?

When the prop RPM gauge enters the Yellow Display Caution Range, it indicates that there is a potential issue that requires attention. This caution range serves as a warning to the pilot or operator that the propeller's RPM is approaching limits that may not be optimal for safe operation. Such a reading should prompt further investigation to ensure that the system is operating correctly and to prevent any potential malfunction.

The caution range plays a crucial role in monitoring the engine's performance, helping to mitigate risks by alerting the operator before reaching a state that could lead to more significant problems. In contrast, normal functionality would be indicated by readings within the green operational range, and any readings in the red zone would indicate that the prop RPM exceeds safe operational limits, requiring immediate corrective action. Recalibration of the instrument is not typically warranted solely based on readings in the caution range; it primarily serves to caution rather than indicate a fault with the gauge itself.