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EASA Part-66 · Licence framework

EASA Part-66 Licence Categories

The aircraft maintenance licence categories — what each one certifies, and exactly which modules it needs.

17

Knowledge modules

A–L

Licence categories

75%

Exam pass mark

Which modules does each category need?

The exact EASA Part-66 module list, live question counts and exam summary for each certifying category:

A
Category A modules Line maintenance · A1–A4
B1
Category B1 modules Mechanical · B1.1–B1.4
B2
Category B2 modules Avionics
B3
Category B3 modules Piston aeroplanes ≤ 2,000 kg

A Category A

Issued after passing the appropriate modules and obtaining the appropriate experience. The person is allowed to sign for certain designated tasks only.

A1 Turbine Engined Aeroplanes
A2 Piston Engined Aeroplanes
A3 Turbine Engined Helicopters
A4 Piston Engined Helicopters
See Category A modules

B Category B

The licence is issued after passing all the appropriate modules and obtaining the appropriate experience. Allows the engineer to sign the Certificate of Release to Service for the aircraft in the category for which he/she is licensed.

B1.1 Turbine Engined Aeroplanes
B1.2 Piston Engined Aeroplanes
B1.3 Turbine Engined Helicopters
B1.4 Piston Engined Helicopters
B2 Avionic
B2L Avionic — limited to endorsed system ratings
B3 Piston engine non-pressurized aircraft below 2,000kg
B1 modules B2 modules B3 modules

C Category C

The licence is issued after obtaining the appropriate experience. Allows the engineer to sign the Certificate of Release to Service following base maintenance on aircraft. Category C is earned through the right combination of B1 or B2 modules — see the applicability matrix.

L Category L

The light-aircraft categories (L1–L5) cover sailplanes, powered sailplanes, balloons, airships and other light or simple aircraft. The licence is issued after passing the appropriate modules and obtaining the appropriate experience for the sub-category.

Licence categories — frequently asked questions

How many EASA Part-66 licence categories are there?
The main aircraft categories are A (line maintenance), B1 (mechanical), B2 (avionics), B2L (avionics limited to endorsed system ratings), B3 (small piston aeroplanes) and C (base maintenance). There is also the L category for light aircraft such as sailplanes and balloons.
What is the difference between Category A and Category B1?
Category A lets you certify a limited list of designated line-maintenance tasks you are authorised for. Category B1 is a full mechanical certifying licence — it covers airframe, engines and mechanical/electrical systems and lets you sign the Certificate of Release to Service.
What is Category B2L?
B2L is a B2 (avionics) licence limited to one or more specific endorsed system ratings — for example communication/navigation, instruments or autoflight — rather than the full B2 scope.
Which category should I study for?
It depends on the aircraft and the type of work you want to certify. See the module applicability matrix and the full Part-66 overview to see which modules each category requires before you choose.
Can I add another category to my licence later?
Yes. You can extend an existing Part-66 licence by passing the additional modules and meeting the experience for the new category — see our licence extension guide.

Free download

How to Become a Licensed Aircraft Engineer

The complete EASA Part-66 handbook — licence categories, all 17 modules, exam format and pass marks, experience and OJT, the rules in 11 countries, type ratings and continuation training. Includes 255 practice questions with explanations. 2026 Edition, PDF.

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