Category A: Line Maintenance Mechanic Licence, A Licence has 4 subcategories;
A1 Aeroplanes Turbine
A2 Aeroplanes Piston
A3 Helicopters Turbine
A4 Helicopters Piston
Category B1: Certifying staff in Line Maintenance and Support Staff in Base Maintenance Licence. Authorised on aircraft structure, powerplant and mechanical and electrical systems, & work on avionic systems requiring only simple tests. B1 licence has 4 subcategories.
B1.1 Aeroplanes Turbine
B1.2 Aeroplanes Piston
B1.3 Helicopters Turbine
B1.4 Helicopters Piston
Category B2: Certifying staff in Line Maintenance and Support Staff in Base Maintenance Licence. Authorised on avionic and electrical systems & electrical and avionics tasks within powerplant and mechanical systems, requiring only simple tests.
Category C: Base maintenance Certifying staff licence.