---
title: "Part-66 Modules and Basic Knowledge Exams · Avioverse"
description: "EASA Part-66 basic knowledge: how modules and knowledge levels work, how the competent-authority examination is run, and how examination credits work."
url: "https://avioverse.aero/guides/part-66-modules-examinations-basic-knowledge"
---

# Part-66 Modules and Basic Knowledge Exams

EASA Part-66 basic knowledge: how modules and knowledge levels work, how the competent-authority examination is run, and how examination credits work.

[Dionysis Kefalas](https://avioverse.aero/articles/author/dennis-kefalas) 11 Jun 2026 Updated 21 Oct 2026 8 min read For training organisation and Part-145 staff

Part 3 of 5 in EASA Part-66 Aircraft Maintenance Licence Show parts Hide parts

1. 1 [EASA Part-66 Licence: Categories and Routes](https://avioverse.aero/guides/easa-part-66-aircraft-maintenance-licence-guide)
2. 2 [Part-66 Categories: A, B1, B2, B3 and C](https://avioverse.aero/guides/part-66-licence-categories-explained)
3. 3 Part-66 Modules and Basic Knowledge Exams
4. 4 [Part-66 Licence: Experience and How to Apply](https://avioverse.aero/guides/part-66-experience-requirements-application)
5. 5 [Part-66 Validity: Type Ratings and Renewal](https://avioverse.aero/guides/part-66-type-ratings-renewal-validity)

Quotes checked on 24 Sep 2026 against EASA Easy Access Rules for Continuing Airworthiness (Regulation (EU) No 1321/2014) — 2 Sep 2025 revision.

On this page

## Basic knowledge — the foundation of the licence

Every Part-66 aircraft maintenance licence rests on the same first step: proving, by examination, that you hold the underlying technical knowledge for the category you are seeking. The experience you log and the type ratings you add later all sit on top of this foundation. Before any of that, you have to demonstrate the basics — and the rule that says so is point 66.A.25.

[66.A.25 (full rule text)](https://avioverse.aero/regulations/easa/continuing-airworthiness/part-66/section-a-technical-requirements/66-a-25) Basic knowledge requirements

> (a) The applicant for an aircraft maintenance licence shall demonstrate by examination a level of knowledge of the related subject modules in accordance with Appendix I (applicable to category A, B1, B2, B2L, B3 and C licences) or Appendix VII (applicable to category L licences).
>
> (b) The basic knowledge examinations shall comply with the standard set out in Appendix II (applicable to category A, B1, B2, B2L, B3 and C licences) or Appendix VIII (applicable to category L licences) to this Annex and shall be conducted by either of the following:
>
> (1) a training organisation approved in accordance with Annex IV (Part-147);
>
> (2) the competent authority;
>
> (3) for category L licences, another organisation as agreed by the competent authority.
>
> (c) The basic knowledge examinations shall have been passed within 10 years prior to the application for an aircraft maintenance licence or the addition of a category or subcategory to such a licence. If the basic knowledge examinations have not been passed within that 10-year period, credits for basic knowledge examinations may be alternatively obtained by the applicant in accordance with point (d).
>
> The 10 years’ validity requirement applies to each individual module examination, except for those module examinations which were already passed as part of another licence category and the licence has already been issued.
>
> \[…]

Quoted word for word from Regulation (EU) No 1321/2014, Easy Access Rules for Continuing Airworthiness, 2 Sep 2025 revision.

Three things to do with this rule. Show the knowledge by examination. Match the modules to the category in Appendix I or Appendix VII. Then read point (c) for the 10 years prior to the application and for the 10 years’ validity requirement. Point (b) lists who may conduct the examinations, including category L. How the competent authority runs an examination is covered later on this page.

## The module structure

The module matrix for categories A, B1, B2, B2L, B3 and C is Appendix I. Category L uses Appendix VII. This guide does not reproduce that matrix or invent module titles, and it does not state what each knowledge level means. Read the current appendix for the set that applies to your category.

What the _rule text_ does confirm is that the module set is real and granular enough to be referenced individually. Point 66.A.25(e) singles out two of them by number when it deals with how a Part-147 basic course is recognised:

[66.A.25 (full rule text)](https://avioverse.aero/regulations/easa/continuing-airworthiness/part-66/section-a-technical-requirements/66-a-25) Basic knowledge requirements

> (e) A basic training course without Modules 1 and 2 of Appendix I to this Annex is considered a full basic training course approved in accordance with Annex IV (Part-147) only when knowledge of those Modules is subsequently demonstrated by the applicant by examination and is credited by the competent authority.
>
> (f) The holder of an aircraft maintenance licence applying for the addition of a different category or subcategory shall complement by examination the level of knowledge that is appropriate to the related subject modules in accordance with Appendix I (for category A, B1, B2, B2L, B3 and C licences) or Appendix VII (for category L licences).
>
> \[…]

Quoted word for word from Regulation (EU) No 1321/2014, Easy Access Rules for Continuing Airworthiness, 2 Sep 2025 revision.

Adding a different category or subcategory is point (f). Read that point before you assume the earlier passes cover the new category.

## How the examination works

Once you know which modules and levels apply, the next question is how the exam is actually conducted. When the competent authority runs the examination itself, point 66.B.200 sets the procedural standard — and it reads like an exam-hall integrity code, because that is precisely what it is.

[66.B.200 (full rule text)](https://avioverse.aero/regulations/easa/continuing-airworthiness/part-66/section-b-procedures-for-competent-authorities/66-b-200) Examination by the competent authority

> (a) All examination questions shall be kept in a secure manner prior to an examination, to ensure that candidates will not know which particular questions will form the basis of the examination.
>
> (b) The competent authority shall nominate:
>
> 1\. persons who control the questions to be used for each examination;
>
> 2\. examiners who shall be present during all examinations to ensure the integrity of the examination.
>
> (c) Basic examinations shall follow the standard specified in Appendices I and II or in Appendices VII and VIII as applicable.
>
> The Certificate of Recognition (CoR) (EASA Form 148b) of Appendix III to Annex IV (Part-147) shall be used to attest completion of basic examinations.
>
> \[…]
>
> (e) New essay questions shall be raised at least every 6 months and questions already used withdrawn or rested from use. A record of the questions used shall be retained in the records for reference.

Quoted word for word from Regulation (EU) No 1321/2014, Easy Access Rules for Continuing Airworthiness, 2 Sep 2025 revision.

The detailed sitting rules continue in the same point, and they are worth knowing before you walk in:

[66.B.200 (full rule text)](https://avioverse.aero/regulations/easa/continuing-airworthiness/part-66/section-b-procedures-for-competent-authorities/66-b-200) Examination by the competent authority

> (f) All examination papers shall be handed out at the start of the examination to the candidate and handed back to the examiner at the end of the allotted examination time period. No examination paper may be removed from the examination room during the allotted examination time period.
>
> \[…]
>
> (h) Examination candidates shall be separated from each other so that they cannot read each other's examination papers. They may not speak to any person other than the examiner.
>
> (i) Candidates who are proven to be cheating shall be banned from taking any further examination within 12 months of the date of the examination in which they were found cheating.

Quoted word for word from Regulation (EU) No 1321/2014, Easy Access Rules for Continuing Airworthiness, 2 Sep 2025 revision.

Read the sitting rules in the quotations before you walk in. The 12-month ban runs from the date of the examination in which the candidate was found cheating. This guide does not state a pass mark or a question count. Those figures are not in this point. Check the current Appendix II for the sitting you face.

## Examination credits

Not every applicant has to sit every module from scratch. Where a technical qualification already covers the same ground, examination credits go through 66.B.400.

[66.B.400 (full rule text)](https://avioverse.aero/regulations/easa/continuing-airworthiness/part-66/section-b-procedures-for-competent-authorities/66-b-400) General

> (a) The competent authority may only grant credit on the basis of a credit report prepared in accordance with point 66.B.405.

Quoted word for word from Regulation (EU) No 1321/2014, Easy Access Rules for Continuing Airworthiness, 2 Sep 2025 revision.

The credit report, under 66.B.405, has to set out a comparison:

[66.B.405 (full rule text)](https://avioverse.aero/regulations/easa/continuing-airworthiness/part-66/section-b-procedures-for-competent-authorities/66-b-405) Examination credit report

> (a) The credit report shall include a comparison between the following:
>
> (i) the modules, submodules, subjects and knowledge levels contained in Appendices I or VII to this Annex (Part-66), as applicable;
>
> (ii) the syllabus of the technical qualification concerned, relevant to the particular category being sought.
>
> This comparison shall state whether compliance has been demonstrated and shall contain the justifications for each statement and the possible conditions or additional considerations, or both.
>
> \[…]
>
> (c) No credit can be granted unless there is a statement of compliance for each module and submodule, indicating where the equivalent standard can be found in the technical qualification.

Quoted word for word from Regulation (EU) No 1321/2014, Easy Access Rules for Continuing Airworthiness, 2 Sep 2025 revision.

A credit is not a blanket acceptance of a qualification. Read the comparison in the quotation, including the statement of compliance for each module and submodule.

Credits are time-limited. Read 66.B.410 for how long they last and what happens when they expire.

[66.B.410 (full rule text)](https://avioverse.aero/regulations/easa/continuing-airworthiness/part-66/section-b-procedures-for-competent-authorities/66-b-410) Examination credit validity

> (a) The competent authority shall notify to the applicant in writing any credits granted together with the reference to the credit report used.
>
> (b) Credits shall expire 10 years after they are granted.
>
> (c) Upon expiration of the credits, the applicant may apply for new credits. The competent authority shall extend the validity of the credits for an additional period of 10 years without further consideration if the basic knowledge requirements defined in Appendices I or VII to this Annex (Part-66), as applicable, have not been changed.

Quoted word for word from Regulation (EU) No 1321/2014, Easy Access Rules for Continuing Airworthiness, 2 Sep 2025 revision.

## Studying for the modules

In practice, basic knowledge is a campaign, not a single exam day. Picture an apprentice at ExampleMRO working toward a category B1 licence, sitting modules around shift work. Check 66.A.25(c) for the 10 years prior to the application and for the 10 years’ validity requirement, and check 66.B.410 for when a credit expires.

Avioverse's certifications tracker can hold module progress and the exam dates behind each pass, so those dates stay visible rather than buried in a folder of old certificates.

Passing the modules, however, only opens the door. A Part-66 licence is issued on knowledge **and** experience, and the experience requirements — how much, of what kind, evidenced how, and how you actually assemble and submit the application — are the subject of the next guide, [Part-66 Experience Requirements and Applying for Your Licence](https://avioverse.aero/guides/part-66-experience-requirements-application). Read this one for the foundation; read that one for the path from a stack of passed modules to a licence in your hand.

Educational content, not regulatory compliance advice. Verify against the current regulation text before relying on it.

## In this series

## Frequently asked questions

### Who can conduct Part-66 basic knowledge examinations?

A Part-147-approved training organisation or the competent authority may conduct Part-66 basic knowledge examinations. For category L, another organisation agreed by the competent authority may also conduct them. Under 66.A.25(b), the applicable examination standards are Appendix II for A, B1, B2, B2L, B3 and C, and Appendix VIII for L.

### Which appendix lists the Part-66 basic knowledge modules?

Appendix I sets out the basic knowledge modules for categories A, B1, B2, B2L, B3 and C; category L uses Appendix VII. The applicable modules depend on the category sought. Under 66.A.25(f), adding a different category or subcategory requires the appropriate additional level of knowledge to be demonstrated by examination.

### How long are Part-66 module examination passes valid?

Under 66.A.25(c), basic knowledge examinations must have been passed within the ten years before the licence application or category addition. This applies to each module individually, except modules already passed as part of another category for which a licence has been issued. For examinations outside the period, examination credits may be obtained under the rule.

### Can a technical qualification earn credits towards Part-66 examinations?

Yes, but credits depend on a credit report under 66.B.400 and 66.B.405. It compares the qualification's syllabus with the relevant modules, submodules, subjects and knowledge levels for the category sought. A statement of compliance is needed for each module and submodule, showing where the equivalent standard is met.

### How long do Part-66 examination credits last?

Examination credits expire ten years after they are granted under 66.B.410. On expiry, the applicant may apply for new credits. If the applicable basic knowledge requirements in Appendix I or VII have not changed, the competent authority extends the credits for another ten years without further consideration.

## Related

- [The EASA Part-66 Aircraft Maintenance Licence: A Complete Guide Guide · 7 min](https://avioverse.aero/guides/easa-part-66-aircraft-maintenance-licence-guide)
- [Part-66 Licence Categories Explained: A, B1, B2, B3 and C Guide · 7 min](https://avioverse.aero/guides/part-66-licence-categories-explained)
- [Part-66 Experience Requirements and Applying for Your Licence Guide · 10 min](https://avioverse.aero/guides/part-66-experience-requirements-application)
- [Keeping Your Part-66 Licence Valid: Type Ratings, Renewal and Recency Guide · 7 min](https://avioverse.aero/guides/part-66-type-ratings-renewal-validity)

Written by Dionysis Kefalas. Retired Hellenic Air Force Captain and founder of Avioverse. [About the author](https://avioverse.aero/articles/author/dennis-kefalas)

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