Aircraft Maintenance and Continuing Airworthiness - Part-66 Licensing
This domain tests Part-66 - the licensing rules that decide who may certify aircraft maintenance and how a licence is obtained, endorsed and kept valid. Questions typically ask you to match a category to its privileges, choose the correct experience route, and explain how type ratings, recent experience and organisation authorisations interact with continuing airworthiness.
Categories and what they may certify
- A - line maintenance: minor scheduled line maintenance and simple defect rectification, limited to tasks endorsed and covered by the organisation's authorisation. No base maintenance.
- B1 - mechanical certifying licence (airframe and engine systems); B2 - avionics and electrical systems. Both certify line and base maintenance within their type ratings.
- B3 - limited licence for non-pressurised aeroplanes at or below 2000 kg MTOM, single-engine piston, maximum four seats; line maintenance only. B2L gives limited avionics privileges on the same light aeroplane group.
- C - base-maintenance certifying staff; not type-rated itself, but the holder must be trained on the type and authorised by the organisation.
Earning and keeping the licence
- Basic knowledge is met by a Part-147 course or by examination at the competent authority (66.A.25), against the Part-66 Appendix I modules.
- Experience (66.A.30) is category-dependent; for B1/B2 the normal requirement is three years of practical maintenance experience, reduced to two years after a Part-147 basic course. Experience must be relevant, recorded and signed off.
- Type ratings are added after Part-147 type training (theory plus practical) and, where required, on-the-job training; the competent authority endorses the type.
- The licence is valid for five years, but privileges may only be exercised with six months of maintenance experience in the preceding two years (66.A.20). Falling outside that does not invalidate the licence, but currency must be regained before certifying.
- The licence never authorises certification by itself: a Part-145 or Part-CAO organisation must issue a certification authorisation defining type and scope.
Worked example
A technician completes a Part-147 B1.1 basic course and has 2 years 2 months of documented turbine-aeroplane experience, with 8 of the last 24 months on the hangar floor. He meets the reduced two-year experience route and the six-months-in-two-years currency rule. He still cannot sign a CRS: he needs the A320 type rating endorsed (type course plus OJT signed off) and a company authorisation within the Part-145 scope.
Traps
- Treating five-year licence validity as the currency rule (it is six months in two years).
- Believing a Part-147 certificate is a licence, or that a type course alone confers certification privileges.
- Assuming an A licence can certify base maintenance or any task not endorsed.
- Forgetting that the organisation's authorisation, not the licence, defines what may be signed.
- Counting unrelated employment as 66.A.30 experience without documentary evidence.