What happens if the PMU aborts an engine start?

When the PMU (Power Management Unit) aborts an engine start, it indicates that the system has detected an abnormal condition during the start-up procedure. In this scenario, it is crucial to understand that subsequent attempts to start the engine should not be executed immediately. This is because the PMU's decision to abort is a protective measure designed to prevent potential damage to the engine or associated systems.

After an abort, pilots must follow proper procedures, which generally include consulting checklists or specific operational protocols to troubleshoot the reason for the abort before making any further attempts. Therefore, taking the time to review checklists ensures that any identified issues are addressed, and all checklists are comprehensively reviewed to maintain safety and operational integrity. The reason for not attempting another start immediately is to avoid exacerbating any underlying problems that may exist, which could lead to a more severe failure or hazardous situation.