Which of the following is considered a corrective maintenance action?

The identification of repairs due to unforeseen events as a corrective maintenance action highlights the nature of corrective maintenance itself. Corrective maintenance is essentially focused on addressing issues or failures after they occur, ensuring that equipment or systems are restored to operational condition. This type of maintenance is often reactive rather than proactive, meaning it is conducted in response to an actual problem or failure that has been discovered, rather than through planned service or routine actions.

In contrast, routine service checks, replacement of an outdated system, and scheduled cleaning of equipment are all proactive measures aimed at maintaining or improving equipment reliability, preventing failures, or ensuring that systems continue to operate effectively. These actions are anticipated and planned as part of standard operational procedures rather than being in direct response to a malfunction. Therefore, they do not fall under the category of corrective maintenance, which is defined specifically by the need to rectify issues that have already arisen.