4. Part-66 Aircraft Maintenance Licences

4.1. The various Licences Part-66


Certifying Staff authorised in accordance with Part-66 will be eligible to hold certification authorisation in one or more of the following categories:


  • Cat A (Line Maintenance Certifying Mechanic):

A aircraft maintenance license permits the holder to issue certificates of release to service following minor scheduled line maintenance and simple defect rectification within the limits of tasks specifically endorsed on the PART-145 regulations.

Cat A licenses includes  the following subcategories:
  • A1: Turbine aeroplane;
  • A2: Piston aeroplane;
  • A3: Turbine helicopter;
  • A4: Piston helicopter.


  • Cat B1 (Maintenance Certifying Technician - Mechanical):

B1 aircraft maintenance license shall permit the holder to issue certificates of release to service and to act as B1 support staff following:

  • maintenance performed on aircraft structure, powerplant and mechanical and electrical systems,
  • work on avionic systems requiring only simple tests to prove their serviceability and not requiring troubleshooting.


Cat B1 licenses includes  the following subcategories:

  • B1.1: Turbine aeroplane;
  • B1.2: Piston aeroplane;
  • B1.3: Turbine helicopter;
  • B1.4: Piston helicopter.


Category B1 includes the corresponding A subcategory.

  • Cat B2 (Maintenance Certifying Technician - Avionics):
B2 license is applicable to all aircraft and concerns the maintenance of the following instruments and avionics.
  • communication/navigation (com/nav),
  • instruments,
  • autoflight,
  • surveillance,
  • airframe systems.


  • Cat B3 (Maintenance Certifying Technician – Light   Aeroplane):

B3 license is applicable to piston-engine non-pressurised aeroplanes of 2 000 kg Maximum Take-off Mass (MTOM) and below.


B2 en relation avec les autres categories

Category B2 concerns all other categories