Quick answer

In aviation, MRO stands for maintenance, repair, and overhaul: the work that keeps aircraft, engines, and components airworthy. The term describes both the activity and the organizations that perform it. In the United States, many MROs hold an FAA repair station certificate under 14 CFR part 145; in EASA states, the comparable approval is a Part-145 maintenance organisation approval.

Maintenance, repair, and overhaul are different jobs

Maintenance covers scheduled inspections, servicing, and the replacement of parts at defined intervals. Repair restores an item after damage, wear, or a defect. Overhaul is the most complete restoration of a component and carries a specific regulatory meaning.

Under 14 CFR 43.2, an item may be described as overhauled only if it has been disassembled, cleaned, inspected, repaired as necessary, and reassembled using acceptable methods, and then tested to approved standards and technical data. That is why buyers should not treat overhauled, repaired, and serviceable as interchangeable conditions.

The main types of aviation MRO

Most MRO work falls into a few broad groups, and many organizations specialize in one or two of them.

  • Line maintenance: checks, servicing, and minor defect rectification between flights
  • Base or heavy maintenance: scheduled checks performed in a hangar over days or weeks
  • Engine MRO: shop visits, module repair, and overhaul of engines and their accessories
  • Component MRO: repair and overhaul of removable units such as wheels, brakes, avionics, and actuators

How MRO organizations are approved

An FAA-certificated repair station operates within the ratings and limitations on its certificate, and may only work on articles it is rated and equipped for. Buyers should confirm that the specific part number falls within the station’s approved capability before sending a unit for repair.

Operators may also perform maintenance under their own programs, and work performed for foreign-registered aircraft may require an approval recognized by that aircraft’s authority. Ask which approvals the release paperwork will reflect.

Where parts sourcing fits into MRO

Every maintenance event creates parts demand: rotables to exchange, expendables to replace, and consumables to complete the job. Delays usually come from a missing part or incomplete records rather than from the labor itself.

A sourcing partner can find replacement units, coordinate repairs through approved MROs, and keep documentation expectations visible from quote to receiving, so the maintenance team is not chasing paperwork after the part arrives.

Frequently asked questions

What does MRO stand for in aviation?

MRO stands for maintenance, repair, and overhaul, the work and organizations that keep aircraft, engines, and components airworthy.

Is an MRO the same as a repair station?

Often, but not always. In the United States many MROs hold an FAA part 145 repair station certificate, while some maintenance is performed by operators under their own maintenance programs.

Does MATS repair components?

For eligible requirements, MATS coordinates repair activity through certified MROs. The repair itself is performed and released by an appropriately approved repair station.

Authoritative sources

This guide provides general procurement information and is not legal, customs, engineering, or airworthiness advice.

14 CFR Part 145: Repair Stations 14 CFR Part 43: Maintenance, Preventive Maintenance, Rebuilding, and Alteration EASA FAQs: Part-145