EASA Part-66 Regulations FAQ for Aircraft Maintenance Engineers
The EASA regulations are one of the core subjects of the Part-66 licence, examined in Module 10 (Aviation Legislation), and they are often the part that gives candidates the most trouble — not because the rules are technically difficult, but because regulatory knowledge requires a different approach to studying. This FAQ covers everything you need to know about Airworthiness Directives, Service Bulletins, EASA Form 1, logbook entries, release to service, and how Skylicence Europe helps you pass with confidence.
Skylicence Europe Team
EASA Part-66 exam preparation specialists — helping engineers earn their Part-66 licence since 2025
Overview of the EASA Regulatory Framework
The EASA regulations are designed to ensure that every certifying engineer in the European Union understands the legal framework that governs aircraft maintenance. Unlike the airframe, powerplant, and electrical modules — which test how aircraft systems work — the legislation module tests what the law requires. This distinction is critical because, as a certifying engineer, you will be legally responsible for making maintenance record entries, certifying that aircraft are fit for release to service, and ensuring AD compliance. The EASA system needs to know that you can be trusted with this legal authority.
The Module 10 exam draws from Regulation (EU) No 1321/2014 and its annexes. The Part-66 Appendix I syllabus defines the learning objectives for the legislation subject area. Topics include licensing rules (Part-66), maintenance organisations (Part-145), continuing airworthiness (Part-M and CAMO), airworthiness directives, the Certificate of Release to Service, EASA Form 1, and the accepted practices used across the system. The legislation questions appear primarily in Module 10, but Part-145 and Part-M requirements also appear in scenario questions across the technical modules.
One of the key challenges of the legislation is the volume of material. The regulation runs to hundreds of pages, and knowing which sections to focus on is essential for efficient study. The exam does not test every section — it focuses on the sections that directly relate to aircraft maintenance and licensing. This is why using a focused study tool like Skylicence Europe, which maps every practice question to the specific learning objectives in Part-66 Appendix I, can save you dozens of hours compared to reading the regulation cover to cover.
Another challenge is the precision required. A single word difference in a regulation can change its meaning entirely, and exam questions are carefully worded to test whether you understand these nuances. Terms like "shall" versus "may," "major repair" versus "minor repair," and "approval" versus "acceptance" all have distinct legal meanings. Skylicence Europe addresses this by including detailed explanations for every answer choice — not just why the correct answer is right, but why each incorrect option is wrong, often with direct regulatory references.
Understanding the Module 10 Exam Format
Module 10 (Aviation Legislation) consists of 64 multiple-choice questions with an 80-minute time limit and a 75 percent pass mark. The exam is administered by approved maintenance training organisations (MTOs) as part of the Part-66 module certification process, and module certificates are issued after you pass. Each module has its own fixed question quota and time limit — Module 10 is 64 questions in 80 minutes.
The question types fall into three general categories. First, definition and recall questions test whether you know specific regulatory terms and content. Second, application questions present a scenario and ask how the regulations apply. Third, reference questions require you to identify which regulation or standard applies to a given maintenance situation. Skylicence Europe simulates all three question types in its practice exams, with adaptive difficulty that adjusts as your performance improves.
Frequently Asked Questions
What are the key EASA regulations for aircraft maintenance engineers?
The EASA system is built on Regulation (EU) No 1321/2014, whose annexes govern nearly everything a certifying engineer does. Annex III (Part-66) establishes the aircraft maintenance licence — categories A, B1.1-B1.4, B2 and B3, the 17 modules, experience requirements, and privileges. Annex II (Part-145) governs approved maintenance organisations and the Certificate of Release to Service. Annex I (Part-M) covers continuing airworthiness, including the CAMO and the airworthiness review. The training organisation framework (formerly Part-147, evolving under Regulation (EU) 2023/989) governs approved maintenance training organisations (MTOs) that deliver the module exams. On Skylicence Europe, the Module 10 bank covers the complete legislation syllabus with practice questions mapped to Part-66 Appendix I.
What is an Airworthiness Directive (AD) and how do I comply?
An Airworthiness Directive is a legally enforceable rule issued by EASA (or a national aviation authority within the EU system) when an unsafe condition exists in an aircraft, engine, propeller, or component. Compliance is mandatory: an aircraft that does not comply with applicable ADs is not airworthy. Engineers must check for applicable ADs before performing maintenance, accomplish the required actions (inspection, repair, modification, or replacement), and record compliance in the maintenance records — including the AD number, the method of compliance, and the signature and licence details of the person certifying the work. Recurring ADs must be re-accomplished at the specified intervals. Skylicence Europe includes AD compliance scenarios with detailed explanations of the recording requirements.
What is the difference between an AD and a Service Bulletin?
An Airworthiness Directive is mandatory — it has the force of a regulation, and the aircraft cannot legally operate without compliance. A Service Bulletin (SB) is a manufacturer-issued document recommending improvements, inspections, or modifications; it is voluntary unless it is incorporated into an AD, required by the continuing airworthiness management organisation (CAMO) maintenance programme, or mandated by the type certificate holder's instructions for continued airworthiness. A common exam question describes an SB and asks whether compliance is mandatory — the answer turns on whether an AD or the approved maintenance programme requires it.
When is the EASA Form 1 required?
The EASA Form 1 is the authorised release certificate for aircraft components, engines, and propellers. It is required whenever a component is released from maintenance by a Part-145 approved maintenance organisation or from production under a POA. The form certifies that the work was performed in accordance with approved data and that the component is in a condition for safe operation. Components without a valid EASA Form 1 — or with an incorrectly completed one — cannot be installed on an aircraft. Minor work performed directly on the aircraft is documented through the Certificate of Release to Service instead of a Form 1.
What must be included in a maintenance logbook entry?
Under the Part-M and Part-145 continuing airworthiness requirements, every maintenance record entry must include: a description of the work performed or a reference to the approved data used; the date of completion; the identity of the person performing the work; and the signature of the certifying staff member with their licence or authorisation details. For component maintenance, the EASA Form 1 provides the record. The owner or CAMO retains these records for the periods specified in the regulations. Records for major repairs and major modifications must reference the approved design data used.
Who can approve an aircraft for release to service?
Under Part-M.A.801 and Part-145.A.50, the release to service is certified by appropriately authorised certifying staff: a B1 licence holder for the mechanical work within their scope, a B2 licence holder for avionics work, or an A category licence holder for the limited line maintenance tasks defined in their privileges. Part-145 organisations issue the Certificate of Release to Service under their maintenance organisation approval. Trainees and uncertified personnel may perform work only under the supervision of certifying staff, who take responsibility and sign the records. Persons without a Part-66 licence may never certify a release to service.
What is the difference between the airworthiness review and a scheduled inspection?
Scheduled inspections are driven by the approved maintenance programme established for the aircraft and managed by the CAMO — they cover the tasks, intervals, and standards defined for each aircraft type. The airworthiness review is a separate, mandatory process that confirms the aircraft remains in a condition for safe operation: it checks the records, verifies AD compliance, and includes a physical survey of the aircraft, ending with the issue of an airworthiness review certificate (ARC). The review must be carried out by the CAMO or an authorised airworthiness review organisation within the required periodicity. Both concepts are core Module 10 material.
Can I perform maintenance tasks without a Part-66 licence?
Yes — under the supervision of certifying staff. Trainees, apprentices, and technicians without a licence may perform maintenance tasks as part of their practical experience, provided the work is supervised and controlled by appropriately licensed certifying staff who remain responsible for it. This is also how the experience required by 66.A.30 is built and documented in a logbook. In addition, some limited tasks may be performed by non-certifying personnel under defined programmes, but the release to service always requires the signature of authorised certifying staff. Understanding the supervision rules is a common scenario on the Module 10 exam.
What happens if I fail a Part-66 module exam?
You can retake a failed module exam at an approved maintenance training organisation (MTO) — there is no limit on the number of attempts, though the MTO may require a minimum gap between attempts and a new registration fee. Your result shows your score by subject area, which tells you exactly which topics to study before retaking. The pass mark is 75 percent (66.A.25). Most candidates benefit from several weeks of focused study before retesting, using the Part-66 Appendix I syllabus and practice questions aligned to it.
How do the regulations differ from the other Part-66 module subjects?
Module 10 (Aviation Legislation) is fundamentally different from the technical modules because it tests legal knowledge rather than mechanical knowledge. While the technical questions ask how systems work and how to troubleshoot them, the legislation questions ask what the law requires — licence privileges, record content, release-to-service authority, AD compliance, and the obligations of organisations. Many candidates find Module 10 harder because it requires a different study approach: precise recall of regulation numbers and rule language rather than understanding physical principles. Skylicence Europe separates Module 10 from the technical modules, allowing you to switch study modes between regulatory and technical content.
How long should I study Module 10 (Aviation Legislation)?
Most candidates spend 2 to 4 weeks on Module 10, depending on their prior exposure to the EASA regulatory system. If you are training at an approved MTO, you will typically cover legislation as part of your course over several months. For self-study candidates, a focused 3-week plan with daily practice is recommended. The key is consistency — studying 30–60 minutes daily is far more effective than cramming for several hours once a week. Skylicence Europe's adaptive difficulty system automatically adjusts to your performance level, ensuring you spend time on the sections where you need the most improvement.
What study resources does Skylicence Europe offer for Part-66 regulations?
Skylicence Europe offers a dedicated Module 10 (Aviation Legislation) question bank with hundreds of practice questions organised by syllabus subject. Features include AI-powered adaptive difficulty that adjusts to your performance, scenario-based questions that simulate real maintenance situations, detailed answer explanations with direct regulatory references, timed mock exams that match the real 64-question, 80-minute format, and performance analytics that show your accuracy by subject. The platform covers the full Part-66 Appendix I legislation syllabus, including Regulation (EU) No 1321/2014, Part-66 licensing, Part-145, Part-M/CAMO, ADs, the CRS, and EASA Form 1. One licence category is free at Skylicence Europe — start practising today.
For more detailed information about the EASA regulations and study strategies, check out our complete EASA Part-66 legislation guide and our Module 10 deep dive. You can also visit the main Skylicence Europe FAQ for platform questions.
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