The Part-66 Licence System
‘Part-66’ is the common European legal framework for certifying licensed aircraft engineers in EASA member states, like the UK. There are three categories:
Category A – Permits the holder to provide limited certification of inspection and maintenance tasks or detect simple rectification.
Category B – Provides the standard licence for practitioners, divided into two subcategories: B1 (mechanics – engines, airframes etc.) and B2(avionics – instrumentation, electrical/ electronic equipment). Holders may provide Certificate of Release of Service of aircraft following maintenance and repair tasks. Category B licences require more in-depth aircraft maintenance knowledge than category A.
Category C – Permits the holder to issue certificates of release to service following base maintenance on aircraft (when the aircraft is stripped down for complete service and overhaul). The work will be carried out by B1 or B2 licensed engineers therefore often a C licence applicant usually already holds a B1 or B2 licence.
All licences are dependent on the completion of appropriate qualifications and obtaining relevant practical experience. Completion of a special Part-147 course allows holders to apply for a Part-66 licence with less practical experience. Aircraft Type rating qualifications are also required which involve carrying out a minumum number of hours on an aircraft type (such as a Boeing 737-800 or Airbus A320), supervised and signed off by a qualified licensed engineer.
Applicants may study for basic licence examinations before they have acquired all the practical experience required as examination passes are valid for up to five years.
You can opt to study independently for your licence and pay for all the costs yourself. If you are on a training scheme or apprenticeship with an aircraft maintenance employer, you should be released for college study and exams etc. as part of your training programme with costs covered by your employer.