TABLE OF CONTENTS Maintenance can be defined as:
Maintenance is any action taken to maintain an item regardless of cause or finding to retain the item in, or restore it to, a specified condition.
US Department of Defense
Much difference of opinion exists relative to what constitutes a failure and what constitutes a maintenance action. To help resolve this problem, categories of failures and maintenance should be assigned when performing maintenance analysis. This categorization and the associated ground rules must be clearly defined, along with documented, assumptions, before an attempt is made to analyze maintenance data. Failures are the inability of an item to perform within specified limits or as the customer/user intends it to. They are actually a subset of maintenance actions.
Maintenance actions are not necessarily caused by failures, but items subject to failure usually require maintenance to be supported. One logistics engineering function concerns supportability, which is a measurement of how well a system or component can be supported. This is comprised of the procurement, replenishment, maintenance, and disposal of systems and components. It includes maintainability, reliability, and human factors concerns.
Supportability often involves the design analysis of how a system or component can fail, how often a failure (and subsequent maintenance) can occur, what effects the failure will have on the rest of the system or end item (vehicle, computer, weapon, and so on), and other related parameters. An explanation of the terms involved is required before examining the formulas...
