In the 3-M system, what does a "backlog" of maintenance refer to?

A "backlog" of maintenance in the 3-M system specifically refers to maintenance tasks that have not been accomplished within their scheduled intervals. This indicates that there are overdue tasks that need to be addressed in order to maintain the operational readiness and effectiveness of equipment. The backlog can accumulate due to a variety of factors such as resource availability, personnel issues, or prioritization of tasks, and it is crucial for a work center supervisor to monitor and manage this backlog to ensure timely maintenance is performed.

The other options provide different scenarios related to maintenance tasks but do not capture the essence of what a backlog entails. For instance, unreported maintenance issues highlight situations where problems have not been documented, which does not specifically relate to scheduled but uncompleted tasks. Scheduled maintenance tasks under review suggests ongoing evaluation, rather than tasks that are overdue. Lastly, completed maintenance tasks awaiting approval pertains to a different stage of the maintenance process, focusing on finalized tasks rather than those that are pending completion. Understanding the definition of a backlog helps in prioritizing and addressing these overdue maintenance tasks effectively.