Organizational-level maintenance (or basic-level maintenance) is the first level of maintenance that can be performed “on-equipment” (directly on the defense article or support equipment) without specialized training. It consists of repairing, inspecting, servicing, calibrating, lubricating, or adjusting equipment, as well as replacing minor parts, components, assemblies, and line-replaceable spares or units. This includes modifications, enhancements, or upgrades that would result in improving only the reliability or maintainability of the commodity (e.g., an increased mean time between failure (MTBF)) and does not enhance the basic performance or capability of the defense article.

Intermediate-level maintenance is second-level maintenance performed “off-equipment” (on removed parts, components, or equipment) at or by designated maintenance shops or centers, tenders, or field teams. It may consist of calibrating, repairing, testing, or replacing damaged or unserviceable parts, components, or assemblies. This includes modifications, enhancements, or upgrades that would result in improving only the reliability or maintainability of the commodity (e.g., an increased mean time between failure (MTBF)) and does not enhance the basic performance or capability of the defense article.

Depot-level maintenance is third-level maintenance performed on- or off-equipment at or by a major repair facility, shipyard, or field team, each with necessary equipment and personnel of requisite technical skill. It consists of providing evaluation or repair beyond unit or organization capability. This maintenance consists of inspecting, testing, calibrating, repairing, overhauling, refurbishing, reconditioning, and one-to-one replacing of any defective parts, components or assemblies. This includes modifications, enhancements, or upgrades that would result in improving only the reliability or maintainability of the commodity (e.g., an increased mean time between failure (MTBF)) and does not enhance the basic performance or capability of the defense article.