___ is sometimes referred to as condition-based maintenance.

• A. Predictive maintenance
• B. Preventive maintenance
• C. Scheduled maintenance
• D. Unscheduled maintenance

Answer: (A)

The main idea is to perform maintenance based on the actual condition of the equipment rather than on a fixed calendar schedule. Predictive maintenance uses data from sensors and other monitoring methods to forecast when a component will fail or its remaining useful life will drop to an unacceptable level, so maintenance can be scheduled just in time. Because the decision to service is driven by real-time or recent condition indicators (like rising vibration, temperature, or lubricant wear), this approach is often described as condition-based maintenance.

This differs from preventive maintenance, which is tied to a calendar or usage interval, and from scheduled maintenance, which follows a predetermined plan regardless of current condition. Unscheduled maintenance is reactive—done after a failure occurs.