Which of the following is an example of Reactive Maintenance (Unplanned Maintenance)?

• A. Replacement of a light bulb
• B. Routine lubrication on a schedule
• C. Software update during planned downtime
• D. Calibration of sensors quarterly

Answer: (A)

Reactive maintenance happens after a fault occurs, with the goal of restoring functionality as quickly as possible. Replacing a burned-out light bulb is a classic example because the action is taken in response to a failure to bring the lighting back online, rather than as part of a scheduled or preventive task. The other activities are planned, preventive actions: routine lubrication to reduce wear, a software update during planned downtime, and calibration at fixed intervals to maintain accuracy. They are designed to prevent issues or maintain performance, whereas the light bulb replacement occurs because something already failed.