Which level of maintenance involves off system component repair and or end item repair and return to the supply system or by exception back to the owning unit performed by national level maintencnace?

The level of maintenance that involves off-system component repair and end item repair, returning them to the supply system or back to the owning unit by exception, is known as Depot Maintenance. This level typically encompasses extensive repairs, overhauls, and modifications that require specialized skills, facilities, and equipment beyond the capabilities of lower maintenance levels.