Part 147 M.T.O.A. (Maintenance Training Organisation Approval) is the European standard for the approval of maintenance training organisations and it has two parts; basic training and aircraft type rating training. The basic training covers requirements for the issue of a Part 66 aircraft maintenance licence, while aircraft type rating training permits to actually operate on the type aircraft.

EASA Continuing Airworthiness Regulation, 1321/2014, is mainly composed by two parts:

  • Part 147
  • Part 66
easa part 66 ame

Part 147 regulates the approval of maintenance training organisations, while Part 66 regulates Certifying Staff. Knowing how to construct your Maintenance Training Organisation Exposition and to write and control training material that meets regulatory requirements is fundamental to maintaining your approval.


The aeronautical maintenance technician plans and applies maintenance interventions consistent with national and European standards on the structure of the aircraft, powerplant and mechanical and electrical systems, testing the functionality of the aircraft of a consistent category, in view of their readmission to service.

He diagnoses malfunctions, identifies and corrects the causes, defines the intervention methods in compliance with international regulations, replaces non-functioning parts with spare parts or intervenes with specific technologies and equipment for their restoration.

However, in order to carry out operations on certified aircraft, it is necessary to have the Aeronautical Maintenance License (AML), obtainable by passing certified theoretical exams (through a Certificate of Recognition) and adequate work experience in approved maintenance companies.

The maintenance technician who wishes to work at the European level must be in possession of the Aeronautical Maintenance License, in at least one of the different categories or sub-categories provided. The issue of the license mentioned above must be requested from the National Civil Aviation Authority, after passing several theoretical and practical exams. In fact, nothing prevents people from continuing their studies, pursuing a degree and advancing their careers once they have graduated from the technical institute, becoming increasingly specialized figures. The various categories and sub-categories classify the type of maintenance technician and are divided into:

  • A: for Technicians with the privilege to operate
    • A1: on Turbine engine Aeroplane
    • A2: on Piston engine Aeroplane
    • A3: on Turbine engine Helicopter
    • A4: on Piston engine Helicopter
  • B1: for Mechanics with the privilege to operate
    • B1.1: on Turbine engine Aeroplane
    • B1.2: on Piston engine Aeroplane
    • B1.3: on Turbine engine Helicopter
    • B1.4: on Piston engine Helicopter
  • B2: for Avionics Category
  • B3: for Technicians with the privilege to operate on Piston engine non-pressurised aeroplanes of 2 000 kg MTOM and below