The categories within the aircraft maintenance licence are:
Category A Maintenance Certifying Mechanic
Category B1 Maintenance Certifying Technician (Mechanical)
Category B2 Maintenance Certifying Technician (Avionic)
Category C Base Maintenance Certifying Engineer
Category A is further divided into sub categories as follows:
A1 Aeroplanes Turbine
A2 Aeroplanes Piston
A3 Helicopters Turbine
A4 Helicopters Piston
The sub categories for Category B Line Maintenance Certifying Technician/Base Maintenance Technician are:
B1.1 Aeroplanes Turbine
B1.2 Aeroplanes Piston
B1.3 Helicopters Turbine
B1.4 Helicopters Piston
B2 Avionics (no further sub division).