Maintainability predictions provide metrics related to the repair of equipment. The main goal of performing a maintainability prediction is to determine the amount of time required to perform repairs and maintenance tasks, so that you are aware of the time it would take and what tasks would be required to bring the system back to an operable state after a failure.

The main metric in maintainability predictions is MTTR (mean time to repair), which various maintainability analysis procedures compute in different ways. Various other repair metrics are important as well, such as MCMT (mean corrective maintenance time) and MPMT (mean preventive maintenance time).

MTTR influences system availability, which is the measure of the likelihood that a system is in an operable state. In many industries, availability is a key measure of system performance, so having an accurate measurement of this metric is crucial. Also, availability can be a metric to verify if the system, as designed, would meet operational requirements.

Maintainability predictions can also help you to identify areas of poor maintainability, which might justify a change in design and/or repair procedures.

To complete a maintainability prediction, you must have failure rate data for the repairable items and data regarding the tasks and associated times to complete repairs. Maintainability predictions are often performed based on established standards. One of the most prominent is MIL-HDBK-472, specifically procedures 2, 5A, and 5B.

If you are unfamiliar with maintainability predictions and would like to study this topic in more detail, refer to MIL-HDBK-472.