Aircraft maintenance is the overhaul, repair, inspection or modification of an aircraft or aircraft component.
Maintenance may include such tasks as ensuring compliance with Airworthiness Directives or Service Bulletins. The maintenance of aircraft is highly regulated, in order to ensure safe and correct functioning during flight. National regulations are coordinated under international standards, maintained by bodies such as the International Civil Aviation Organization (ICAO). The maintenance tasks, personnel and inspections are all tightly regulated and staff must be licensed for the tasks they carry out.
The Maintenance, Repair, Overhaul (MRO) Market was US$135.1 Billion in 2015, three quarters of the $180.3 B aircraft production market. Of this, 60% is for civil aviation : air transport 48%, business and general aviation 9%, rotorcraft 3% ; and military aviation is 40% : fixed wing 27% and rotary 13%. Of the $64.3 Billion air transport MRO market, 40% is for engines, 22% for components, 17% for line, 14% for airframe and 7% for modifications. Its is projected to grow at 4.1% per annum till 2025 to $96B.
Aircraft maintenance is highly regulated, because the smallest slip can lead to an aircraft crashing with consequent loss of life. The International Civil Aviation Organization (ICAO) sets global standards which are then implemented by national and regional bodies around the world.
Local airworthiness authorities include:
The International Civil Aviation Organization (ICAO) defines the licensed role of aircraft maintenance (technician/engineer/mechanic), noting that "The terms in brackets are given as acceptable additions to the title of the license. Each Contracting State is expected to use in its own regulations the one it prefers." Thus, aircraft maintenance technicians, engineers and mechanics all perform essentially the same role. However different countries use these terms in different ways to define their individual levels of qualification and responsibilities.