EASA Part-66 Standards & Documentation FAQ for Certifying Staff
The EASA maintenance standards — Regulation (EU) No 1321/2014 with its Part-66, Part-145 and Part-M annexes, the Certificate of Release to Service, EASA Form 1, Airworthiness Directives, and maintenance records — govern everything a certifying engineer signs. Module 10 (Aviation Legislation) examines this framework directly, and documentation rules also appear throughout the technical modules and in daily maintenance work. This FAQ covers the standards, the paperwork, and how Skylicence Europe helps you master them.
Skylicence Europe Team
EASA Part-66 exam preparation specialists — helping engineers earn their Part-66 licence since 2025
The Regulatory Foundation of Part-66 Work
Every certifying engineer works inside a framework of EU regulations, and the Module 10 exam expects you to know them cold. At the centre is Regulation (EU) No 1321/2014, whose Annex III (Part-66) defines the aircraft maintenance licence: the categories (A, B1.1-B1.4, B2, B3), the 17 modules of Appendix I, the experience requirements of 66.A.30, and the privileges of certifying staff. Around it sit Annex II (Part-145) for maintenance organisations, Annex I (Part-M) for continuing airworthiness and CAMO, and the evolving training organisation framework of Regulation (EU) 2023/989.
The Module 10 exam draws directly from this framework: 64 questions in 80 minutes, with a 75 percent pass mark. Questions cover the structure of the regulation, licence privileges and limitations, the obligations of certifying staff when signing a Certificate of Release to Service, and the documentation trail — EASA Form 1, AD compliance records, and maintenance logbook entries. The technical modules assume you can apply those rules to specific systems — for example, knowing what data is required before a structural repair can be released, or what entry is required after replacing an engine.
The documentation side is just as important as the technical side. The CRS for aircraft, EASA Form 1 for components, logbook entries, and AD compliance records form the legal trail that proves an aircraft is airworthy. An engineer who cannot document work correctly is a liability, no matter how skilled with tools. Skylicence Europe treats documentation as a first-class subject, with scenario questions that build the habits the EASA system expects.
Release to Service: The Certifying Staff Signature
Release to service is the moment when maintenance documentation meets airworthiness. Under Part-M.A.801 and Part-145.A.50, no one may release an aircraft after maintenance without the proper records, and the signature on a CRS — with your licence details and the organisation authorisation — is a legal certification that the work was performed correctly and the aircraft is safe for flight. For components, the EASA Form 1 is the equivalent record. For the airworthiness review, the airworthiness review certificate confirms the aircraft remains in a condition for safe operation. Understanding exactly what each signature authorises — and what it does not — is one of the most important professional competencies the Part-66 exams test.
Frequently Asked Questions
What are the EASA maintenance standards and documentation rules?
The EASA maintenance framework is built on Regulation (EU) No 1321/2014, whose annexes govern every stage of continuing airworthiness: Annex I (Part-M) covers continuing airworthiness management, including the CAMO role; Annex II (Part-145) covers approved maintenance organisations; Annex III (Part-66) covers the aircraft maintenance licence; and Annex IV (Part-147, evolving via Regulation (EU) 2023/989) covers maintenance training organisations (MTOs). Documentation rules cover logbook entries, the Certificate of Release to Service (CRS), EASA Form 1 for components, and AD compliance records. Skylicence Europe includes a dedicated Module 10 (Aviation Legislation) question bank covering these requirements with practice questions.
What does Module 10 cover and why is it tested?
Module 10 (Aviation Legislation) is the EASA equivalent of a regulations exam: 64 questions in 80 minutes with a 75 percent pass mark (66.A.25). It covers the regulatory framework — Regulation (EU) No 1321/2014 and its annexes — plus the role of the International Civil Aviation Organization (ICAO), the EASA system and its member states, Part-66 licensing (categories A, B1.1-B1.4, B2, B3, privileges, and limitations), Part-145 maintenance organisation requirements, Part-M continuing airworthiness management, the Certificate of Release to Service, EASA Form 1, airworthiness review certificates, and the obligations of certifying staff. It is heavily tested because every certifying engineer signs entries governed by it. Skylicence Europe breaks Module 10 down by syllabus subject with scenario questions that mirror real sign-off situations.
What is the EASA Form 1 and when is it required?
The EASA Form 1 is the authorised release certificate for aircraft components, engines, and propellers. It is issued when a component is released from a Part-145 approved maintenance organisation after maintenance, or by a production organisation under its POA. The form certifies that the work was performed in accordance with the approved data and that the component is in a condition for safe operation. It accompanies the component through its service life and is the basis for installing it on an aircraft. Knowing what a compliant EASA Form 1 must contain — the form number, the issuing organisation, the component description, the approved data references, and the signature of the authorised release person — and what makes a form invalid, is a frequently tested distinction.
What are Airworthiness Directives (ADs) and how is compliance documented?
Airworthiness Directives are legally enforceable rules issued by EASA (and national authorities within the EU regulatory system) when an unsafe condition exists in a product. They may require inspection, modification, replacement, or operational limitations, and compliance is mandatory. AD compliance must be recorded in the aircraft maintenance records with the AD number, the method of compliance, the date, and the signature and licence number of the person who complied. If an AD is not complied with, the aircraft is not airworthy. Tracking AD compliance — including identifying which ADs apply to a specific airframe, engine, propeller, or component — is a core certifying staff responsibility and a frequent Module 10 exam topic.
What must a maintenance logbook entry contain?
Under the Part-M continuing airworthiness requirements, maintenance records must contain: a description of the work performed, referencing the approved data used; the date of completion; the identity of the person performing the work; and the signature of the certifying staff member who releases the aircraft to service, with their licence or authorisation details. For maintenance performed by a Part-145 organisation, the CRS certifies the work, and the corresponding entries are retained in the organisation and aircraft records. Entries must be legible, complete, and retained for the periods specified in the regulations. Skylicence Europe includes logbook-entry scenarios that test exactly what belongs in a compliant entry.
What is the difference between a major repair and a minor repair under EASA?
In the EASA system, repairs and modifications are classified through the approved data that governs them. A major repair or major modification is one that requires design approval — for example, a repair that goes beyond the limits of the structural repair manual (SRM) and needs an approved design from a Design Approval Holder (DAH) or an organisation with design approval (DOA). Minor repairs and minor modifications can be accomplished using the data specified in Part-M and the maintenance instructions, without a separate design approval. The classification determines the data required and how the work is documented. Understanding how to classify work against the applicable data is one of the most tested concepts in Module 10 documentation questions.
What is the Certificate of Release to Service (CRS)?
The Certificate of Release to Service is the document by which a maintenance organisation or certifying staff member certifies that maintenance has been performed correctly and the aircraft is fit to fly. For line and base maintenance, the CRS is issued by appropriately authorised certifying staff — a B1 or B2 licence holder, or an A category licence holder for the limited tasks within their privileges — in accordance with Part-M.A.801 or Part-145.A.50. The CRS references the work performed, the data used, and the maintenance organisation. No aircraft may operate after maintenance without a valid CRS. Understanding who may sign a CRS, and under what authorisation, is one of the most heavily tested Module 10 topics.
Who can perform maintenance and release an aircraft to service?
Maintenance can be performed by Part-145 approved maintenance organisations and, within defined limits, by certifying staff holding an EASA Part-66 licence appropriate to the work. The release to service requires the appropriate records: a CRS signed by certifying staff for the work performed, and an EASA Form 1 for components released from maintenance. Licence categories define the scope: B1 covers mechanical maintenance and can sign CRS for the airframe and engine tasks within its scope; B2 covers avionics; A category licences cover limited line maintenance tasks; B3 covers non-pressurised piston helicopters. Trainees work under the supervision of certifying staff, who take responsibility for the work. Understanding who is authorised to sign what is essential — and heavily tested.
What approved data can be used for repairs and modifications?
Maintenance, repairs, and modifications must be performed using the approved data applicable to the aircraft: the manufacturer maintenance manuals (AMM), structural repair manual (SRM), and service bulletins; approved design data from the type certificate holder or a DOA; and, where applicable, the instructions for continued airworthiness. EASA Form 1 components and the airworthiness review certificate also form part of the airworthiness record. Using the correct data — and knowing when design approval is required — is a core competency tested on the Module 10 exam and applied daily by certifying staff in Part-145 and CAMO environments.
How do Part-66, Part-145 and Part-M relate to each other?
Part-66 (Annex III to Regulation (EU) No 1321/2014) defines the aircraft maintenance licence: the categories, the 17 modules, the experience requirements (66.A.30 — for example 5 years for B1.1 and B2, reducible with recognised training), and the privileges of certifying staff. Part-145 (Annex II) governs approved maintenance organisations: their facilities, personnel, quality systems, and the release to service of aircraft and components. Part-M (Annex I) governs continuing airworthiness: the CAMO, the airworthiness review process, and the obligations of owners and operators. Many engineers work in Part-145 environments managed by a CAMO, so understanding how the three annexes interact is important Module 10 material.
What happens if maintenance documentation is incorrect or missing?
Incorrect or missing documentation is a serious matter. The EASA system can take enforcement action, and an aircraft with incomplete records may be considered non-airworthy until records are corrected or the work is re-accomplished. Logbook entries and CRSs cannot be erased — errors are corrected by lining through the error, initialling the correction, and making the correct entry. If required records are missing, the competent authority may require re-inspection of the work or acceptance of alternative evidence. For certifying staff, the practical consequences include failed audits, certificate action, and liability. Learning to make complete, accurate entries the first time is a professional skill evaluated throughout your career — and tested on the Module 10 exam.
How does Skylicence Europe help me master EASA standards and documentation?
Skylicence Europe includes a dedicated Module 10 (Aviation Legislation) bank covering Regulation (EU) No 1321/2014, Part-66 licensing, Part-145 organisations, Part-M and CAMO, AD compliance, the CRS, and EASA Form 1 scenarios. Features include AI-powered adaptive difficulty, detailed explanations with exact regulatory references, timed mock exams matching the real 64-question, 80-minute format, and analytics showing your accuracy by syllabus subject. One licence category is free on the FREE plan; PRO unlocks all 17 modules with unlimited practice. Create a free account at Skylicence Europe to start mastering the standards today.
For a deeper look at the EASA documentation rules, check out our aviation maintenance glossary and EASA Part-66 study guide. Visit the main Skylicence Europe FAQ for platform-related questions.
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