Maintenance (technical)

Mechanical repair
Field repair of aircraft engine (1915–1916)

The technical meaning of maintenance involves functional checks, servicing, repairing or replacing of necessary devices, equipment, machinery, building infrastructure, and supporting utilities in industrial, business, governmental, and residential installations.[1][2] Over time, this has come to include multiple wordings that describe various cost-effective practices to keep equipment operational; these activities take place either before[3] or after a failure.

Together, these functions are referred to as Maintenance, repair and overhaul (MRO). MRO is also used for Maintenance, repair and operations.[4]

Over time, the terminology of maintenance and MRO has begun to become standardized. The United States Department of Defense uses the following definitions:[5]

  • Any activity—such as tests, measurements, replacements, adjustments, and repairs—intended to retain or restore a functional unit in or to a specified state in which the unit can perform its required functions.[5]
  • All action taken to retain material in a serviceable condition or to restore it to serviceability. It includes inspections, testing, servicing, classification as to serviceability, repair, rebuilding, and reclamation.[5]
  • All supply and repair action taken to keep a force in condition to carry out its mission.[5]
  • The routine recurring work required to keep a facility (plant, building, structure, ground facility, utility system, or other real property) in such condition that it may be continuously used, at its original or designed capacity and efficiency for its intended purpose.[5]

Maintenance is strictly connected to the utilization stage of the product or technical system, in which the concept of maintainability must be included. In this scenario, maintainability is considered as the ability of an item, under stated conditions of use, to be retained in or restored to a state in which it can perform its required functions, using prescribed procedures and resources.[6][7]

In some domains like aircraft maintenance, terms maintenance, repair and overhaul[8] also include inspection, rebuilding, alteration and the supply of spare parts, accessories, raw materials, adhesives, sealants, coatings and consumables for aircraft maintenance at the utilization stage. In international civil aviation maintenance means:

  • The performance of tasks required to ensure the continuing airworthiness of an aircraft, including any one or combination of overhaul, inspection, replacement, defect rectification, and the embodiment of a modification or a repair.[9]

This definition covers all activities for which aviation regulations require issuance of a maintenance release document (aircraft certificate of return to service – CRS).

Road repair


The marine transportation,[10] offshore structures,[11] industrial plant and facility management industries depend on maintenance, repair and overhaul (MRO) including scheduled or preventive paint maintenance programmes to maintain and restore coatings applied to steel in environments subject to attack from erosion, corrosion and environmental pollution.[11]

Other Languages
العربية: صيانة
català: Manteniment
español: Mantenimiento
فارسی: اورهال
hrvatski: Održavanje
italiano: Manutenzione
Кыргызча: Ремонт
Nederlands: Onderhoud
srpskohrvatski / српскохрватски: Održavanje
svenska: Reparation
Zazaki: Tamirkar
中文: 維護