What should be done if the PMU fails during startup?

Cycling the PMU (Power Management Unit) is a standard troubleshooting step when it fails during startup. This procedure involves turning the PMU off and then back on again, which can sometimes reset the unit and allow it to function properly. The PMU is critical for managing aircraft engine performance and its initial faults might be temporary, so cycling it may resolve any glitches encountered during startup.

This step is also a part of the normal operating procedures when dealing with electrical or system failures, as it can help restore functionality without requiring immediate maintenance intervention. By attempting this before escalating the issue, pilots ensure that they are taking every precaution possible to maintain operational safety and efficiency. If cycling the PMU does not rectify the issue, further steps such as notifying the maintenance crew would be necessary.