Preventive maintenance (PM) has the following meanings:

1. The care and servicing by personnel for the purpose of maintaining equipment and facilities in satisfactory operating condition by providing for systematic inspection, detection, and correction of incipient failures either before they occur or before they develop into major defects.
2. Maintenance, including tests, measurements, adjustments, and parts replacement, performed specifically to prevent faults from occurring.

Source: from Federal Standard 1037C and from MIL-STD-188 and from the Department of Defense Dictionary of Military and Associated Terms

While preventive maintenance is generally considered to be worthwhile, it is important to note that there are risks such as equipment failure or human error involved when performing PM, just as in any maintenance operation. PM is also sometimes augmented by reliability centered maintenance, which attempts to determine the best PM tasks, and by predictive maintenance, which models past behavior to predict failures.

The phrase 'preventive maintenance' (and its sibling 'preventative maintenance') is used to differentiate from maintenance that is performed to fix a problem after it has occurred.

External links

• Is Preventive Maintenance Necessary?

• Products normally used by turbine overhaul companies during MRO operations