Module 10: Aviation Legislation — EASA Part-66 Category B3

1. Overview of Module 10

Module 10 of the EASA Part-66 basic knowledge syllabus provides the regulatory foundation for aircraft maintenance certifying staff. It covers the legal framework governing civil aviation in the European Union, with particular emphasis on the regulations that directly govern the certification, performance, and release of maintenance work.

For the B3 category (light helicopters and small non-complex aeroplanes with a maximum take-off mass not exceeding 2,725 kg), this module ensures that certifying staff understand:

The structure of EU aviation regulations and the hierarchy of legal documents
The specific requirements of Part-66 (licensing of maintenance personnel)
The requirements of Part-145 (approved maintenance organisations)
The requirements of Part-M (continuing airworthiness)
The privileges, responsibilities, and limitations of a B3 licence holder
The procedures for certification of maintenance and release to service
The reporting obligations and occurrence reporting systems

This module is examined at knowledge levels 1, 2, and 3 depending on the subtopic. Level 3 (detailed theory) applies to the core responsibilities of certifying staff, the conditions for issuing a Certificate of Release to Service (CRS), and the privileges of the licence.

2. The Regulatory Framework

2.1 The Hierarchy of EU Aviation Legislation

The European Union aviation regulatory system operates on a hierarchical structure:

The Basic Regulation — Regulation (EU) 2018/1139 (formerly Regulation (EC) No 216/2008) establishes the European Union Aviation Safety Agency (EASA) and sets the overarching legal framework for civil aviation safety in the EU.
Implementing Regulations — These are binding legal acts that implement the Basic Regulation. The most relevant for maintenance personnel are:

Regulation (EU) No 1321/2014 — the continuing airworthiness regulation, containing:
Annex I (Part-M) — continuing airworthiness requirements for aircraft
Annex II (Part-145) — requirements for maintenance organisations
Annex III (Part-66) — requirements for the licensing of maintenance personnel
Annex IV (Part-147) — requirements for maintenance training organisations
Regulation (EU) No 748/2012 — the initial airworthiness regulation, containing Part-21 (certification of aircraft and related products, parts, and appliances)

Acceptable Means of Compliance (AMC) and Guidance Material (GM) — These are non-binding documents issued by EASA that provide acceptable methods of demonstrating compliance with the regulations. Alternative methods may be used if they are shown to be equivalent.
Certification Specifications (CS) — Technical standards used for the certification of products, parts, and appliances.

2.2 Key Definitions

Term	Definition
Certifying staff	Personnel authorised to sign a Certificate of Release to Service (CRS) after maintenance
Certificate of Release to Service (CRS)	The document attesting that maintenance has been performed correctly and the aircraft is airworthy
Continuing airworthiness	All processes ensuring that an aircraft complies with its approved design and is safe for operation
Maintenance	Any one or combination of overhaul, repair, inspection, replacement, modification, or defect rectification
Life-limited part	A part with a mandatory replacement interval defined in the approved maintenance data
Type rating	The specific aircraft type(s) for which a licence holder has completed training and is authorised to certify

3. Part-66 — Licensing of Maintenance Personnel

3.1 The Aircraft Maintenance Licence (AML)

Part-66 (Annex III to Regulation (EU) No 1321/2014) establishes the requirements for the issue, renewal, and privileges of the Aircraft Maintenance Licence.

Key provisions of Part-66.A.10 (Application and validity):

The AML is issued by the competent authority of an EU Member State
The licence has unlimited validity — it does not require periodic renewal
The licence may be revoked, suspended, or limited by the competent authority if the holder fails to meet the requirements
The licence remains valid provided the holder continues to meet the experience requirements

Minimum age requirement: An applicant for an AML must be at least 18 years of age (Part-66.A.5(a)).

3.2 Licence Categories

Part-66 defines several licence categories. The B3 category is specifically for:

Light helicopters (maximum take-off mass not exceeding 3,175 kg)
Small non-complex aeroplanes (maximum take-off mass not exceeding 2,725 kg)

The B3 licence covers the entire aircraft, including the airframe, engines (piston/reciprocating), electrical systems, and avionics systems. It does not cover turbine engines — for turbine-powered aircraft, a different category (B2 or B1 with appropriate subcategory) is required.

Mandatory examination modules for B3 (Part-66 Appendix I):

Module	Subject
Module 1	Mathematics
Module 2	Physics
Module 3	Electrical Fundamentals
Module 4	Electronic Fundamentals
Module 5	Digital Techniques / Electronic Instrument Systems
Module 6	Materials and Hardware
Module 7	Maintenance Practices
Module 8	Basic Aerodynamics
Module 9	Human Factors
Module 10	Aviation Legislation
Module 11	Aeroplane Aerodynamics, Structures, and Systems
Module 12	Helicopter Aerodynamics, Structures, and Systems
Module 13	Aircraft Aerodynamics, Structures, and Systems (not applicable to B3)
Module 14	Propulsion (piston engines)
Module 15	Gas Turbine Engine (not applicable to B3)
Module 16	Piston Engine (not applicable to B3)
Module 17	Propeller (not applicable to B3)

Note: Module 15 (Gas Turbine Engine) is not a mandatory requirement for the B3 category. Module 14 (Propulsion) covers the piston engine requirements for B3.

3.3 Privileges of the B3 Licence

Part-66.A.20 defines the privileges of the licence holder:

The B3 licence authorises the holder to certify maintenance (issue CRS) on aircraft covered by the B3 category
The holder may also supervise maintenance performed by unlicensed personnel
The holder must have the appropriate type rating for the specific aircraft type

Type ratings for B3: Unlike some other categories, B3 type ratings are granted for specific aircraft types (e.g., Robinson R22, Cessna 172). The holder must complete type training and pass the relevant examination to obtain a type rating.

3.4 Requirements for Exercising Licence Privileges

Part-66.A.20(e) specifies that to exercise the privileges of the licence, the holder must have:

At least 6 months of relevant maintenance experience in the preceding 2 years, OR
Met the requirements for refresher training as determined by the competent authority

This requirement ensures that certifying staff maintain current knowledge and practical competence.

3.5 Suspension and Revocation

If a licence is suspended or revoked (Part-66.A.20(b)), the applicant may regain it by:

Completing a refresher training course as determined by the competent authority
Passing the applicable examinations

This ensures that the certifying staff member demonstrates current knowledge before the licence is reinstated.

3.6 Responsibilities of the Licence Holder

The licence holder is personally responsible for:

Ensuring that all maintenance certified has been performed in accordance with approved data
Ensuring that the aircraft is airworthy and safe for operation
Ensuring that all required documentation is complete before issuing a CRS
Maintaining their own competence and recent experience
Reporting any defects or occurrences that could affect the safe operation of the aircraft

4. Part-145 — Approved Maintenance Organisations

4.1 Scope and Applicability

Part-145 (Annex II to Regulation (EU) No 1321/2014) establishes the requirements for organisations performing maintenance on aircraft and components. A Part-145 approval is required for:

Maintenance of aircraft used for commercial operations
Maintenance of components (unless performed by the aircraft owner under specific conditions)
Any maintenance performed by an organisation that issues an EASA Form 1

4.2 Personnel Requirements (Part-145.A.30)

The maintenance organisation must ensure that:

All personnel performing maintenance are trained and qualified for the tasks assigned
Certifying staff hold the appropriate Part-66 licence and type rating
Unlicensed personnel may perform maintenance only under the direct supervision of certifying staff or appropriately qualified personnel
Task-specific training is provided and recorded

Direct supervision means that the supervisor must be present and able to provide immediate guidance and inspection of the work. Merely checking the final result after the work is completed does not constitute direct supervision.

4.3 Certification of Maintenance (Part-145.A.50)

Part-145.A.50 establishes the requirements for the certification of maintenance:

A Certificate of Release to Service (CRS) must be issued after any maintenance is completed
The CRS may only be issued by authorised certifying staff
The certifying staff member must have personally performed or directly supervised the work
The maintenance must have been performed in accordance with approved data
The aircraft must be airworthy and safe for operation

Key principle: The CRS is not a mere formality — it is a legal attestation of airworthiness. The certifying staff member who signs the CRS takes personal responsibility for the maintenance performed. This responsibility is personal and cannot be transferred to the organisation.

Conditions for issuing a CRS:

All required maintenance has been properly carried out
The maintenance was performed in accordance with approved data
The certifying staff member has control over the maintenance performed
The certifying staff member has personally performed or directly supervised the work
No defects remain that would affect the safe operation of the aircraft
All required documentation is complete

4.4 Tools and Equipment (Part-145.A.40)

The maintenance organisation must ensure that:

All tools and equipment are controlled and calibrated
Tools are appropriate for the tasks being performed
The correct tools are used for each task

Important principle: The maintenance data specifies torque values and other parameters in specific units. Using tools calibrated in different units introduces a risk of error and is not acceptable unless the approved data explicitly permits alternative units. The certifying staff must use the specified tools.

4.5 Maintenance Data (Part-145.A.45)

The organisation must ensure that:

All applicable maintenance data is available and current
Maintenance is performed in accordance with the approved data
Any deviations from the approved data require prior approval

Approved data includes:

The manufacturer's maintenance manual (AMM), structural repair manual (SRM), and component maintenance manual (CMM)
Airworthiness Limitations Section (ALS) of the Instructions for Continued Airworthiness
Service bulletins and airworthiness directives
Data approved by the competent authority

4.6 Occurrence Reporting (Part-145.A.60)

Part-145.A.60 requires that:

Any defect, malfunction, or occurrence that could affect the safe operation of an aircraft must be reported
Reports are made to the competent authority through the organisation's reporting system
Reports are also made to the quality manager in accordance with the organisation's procedures

This is a key safety responsibility of certifying staff. Failure to report a significant defect is a violation of Part-145 and could lead to enforcement action.

5. Part-M — Continuing Airworthiness

5.1 Scope and Applicability

Part-M (Annex I to Regulation (EU) No 1321/2014) establishes the continuing airworthiness requirements for aircraft. It applies to:

All aircraft registered in an EU Member State
All aircraft operated by EU operators

5.2 Responsibilities of the Owner (Part-M.A.201)

The owner of an aircraft is responsible for:

Ensuring that the aircraft is maintained in an airworthy condition
Ensuring that any defect that could affect safety is rectified before flight
Ensuring that maintenance is performed in accordance with the approved maintenance programme
Ensuring that all applicable airworthiness directives are complied with

The owner may contract a Part-145 organisation or a Part-M Subpart F maintenance organisation to carry out the work, but the ultimate responsibility remains with the owner.

5.3 The Maintenance Programme (Part-M.A.302)

The maintenance programme must:

Be approved by the competent authority
Be based on the manufacturer's recommendations
Include all mandatory requirements (e.g., airworthiness limitations)
Be reviewed and updated as necessary

Important principle: Any change to the maintenance programme, including extending inspection intervals, requires approval by the competent authority. The CAMO cannot unilaterally change the programme. The approval process may involve a reliability analysis or other evidence demonstrating that the safety level is maintained.

5.4 Continuing Airworthiness Management (Part-M Subpart F)

A Continuing Airworthiness Management Organisation (CAMO) may be contracted to manage the continuing airworthiness of an aircraft. The CAMO is responsible for:

Developing and managing the maintenance programme
Ensuring that maintenance is performed by an appropriate organisation
Tracking airworthiness directives and service bulletins
Maintaining the aircraft's maintenance records

A written maintenance contract must be in place between the owner/operator and the CAMO (Part-M.A.201). This contract must define the responsibilities and scope of work.

5.5 Airworthiness Limitations

Life-limited parts have mandatory replacement intervals defined in the approved maintenance data (typically in the Airworthiness Limitations Section of the Instructions for Continued Airworthiness). These limits:

Are mandatory and cannot be extended without an approved design change
Are approved by EASA or the State of Design
Must be tracked and complied with

A crack in a critical component (e.g., a main rotor blade) renders the aircraft unairworthy. Extensions are only possible through a modification approved by EASA or the State of Design.

6. Part-21 — Design and Production Approval

6.1 Scope and Applicability

Part-21 (Annex I to Regulation (EU) No 748/2012) establishes the requirements for the certification of aircraft and related products, parts, and appliances. It covers:

Type certification
Production certification
Airworthiness certification
Approval of design changes and repairs

6.2 Approval of Repairs (Part-21.A.433)

When a repair is not covered by existing approved maintenance data:

The repair design requires approval in accordance with Part-21
The approval may be issued by EASA or by a Design Organisation Approval (DOA) holder with the appropriate scope
The certifying staff member cannot approve the design — they can only certify the embodiment of the repair using approved data
The OEM may provide data, but the approval must come from a Part-21 design organisation or the competent authority

Key principle: A certifying engineer may only certify maintenance after ensuring that all required maintenance has been properly carried out in accordance with approved data. Any repair not covered by approved data requires approval from the competent authority or use of data approved by the competent authority.

7. The Certificate of Release to Service (CRS)

7.1 Purpose and Legal Significance

The CRS is the document that:

Attests that maintenance has been performed correctly
Confirms that the aircraft is airworthy and safe for operation
Is a legal attestation of airworthiness
Establishes personal responsibility of the certifying staff member

7.2 Conditions for Issuing a CRS

The certifying staff member may issue a CRS only when all of the following conditions are met:

All required maintenance has been properly carried out — including all scheduled inspections and any defect rectification
The maintenance was performed in accordance with approved data — no deviations from the approved data are permitted
The certifying staff member has personally performed or directly supervised the work — signing a CRS for work not performed or supervised is a violation
The certifying staff member holds the appropriate licence category and type rating — experience alone or supervision does not substitute for the required licence
The aircraft is airworthy and safe for operation — no known defects that could affect safety remain
All required documentation is complete — including maintenance records and any applicable forms

7.3 Personal Responsibility

The certifying staff member who signs the CRS:

Takes personal responsibility for the maintenance performed
Is responsible for ensuring that all required inspections are completed
Is responsible for the airworthiness of the aircraft
Cannot transfer this responsibility to the organisation
May be subject to enforcement action (including licence revocation) for violations

Critical point: If a defect is found after a CRS has been issued that was present before the CRS was issued but was not detected during the inspection, the certifying staff member who signed the CRS is primarily responsible.

8. Maintenance Personnel — Qualification and Supervision

8.1 Licensed vs. Unlicensed Personnel

Licensed personnel (certifying staff):

Hold a Part-66 licence with the appropriate category and type rating
Are authorised to issue CRS
May supervise unlicensed personnel

Unlicensed personnel (trainees/mechanics):

May perform maintenance tasks
Must work under the direct supervision of certifying staff or appropriately qualified personnel
Do not have the authority to issue CRS

8.2 Requirements for Task Performance

Part-145.A.30 requires that:

Personnel performing maintenance are trained and qualified for the tasks assigned
The B3 licence is a base qualification — the organisation must provide task-specific training and authorisation
The certifying staff member is responsible for ensuring that the person performing the task is competent
Type ratings are required for certifying staff, not necessarily for mechanics, but task training is mandatory

8.3 Direct Supervision

Direct supervision means that the supervisor:

Must be present and able to provide immediate guidance
Must be able to inspect the work
Must have control over the maintenance performed

Merely checking the final result after the work is completed does not constitute direct supervision.

9. Defect Deferral and Maintenance Programme Compliance

9.1 Deferred Defects

A release to service may only be issued when all required maintenance has been properly carried out. A defect may be deferred only when:

The deferral is explicitly allowed by the approved maintenance data (e.g., MEL/CDL)
The deferral is permitted by the maintenance programme
The deferral is recorded in accordance with the organisation's procedures

Important principle: Verbal notification or substitution of materials without approval violates the approved maintenance data and Part-145 requirements.

9.2 Lubrication and Scheduled Maintenance

A lubrication task is part of the scheduled maintenance. If it cannot be completed:

The aircraft is not airworthy unless an approved deferral exists
The correct grease must be used — substitution without approval is not permitted
The certifying staff must not issue a CRS until the task is completed or an approved deferral is in place

10. Units of Measurement and Tooling

10.1 Correct Use of Units

The maintenance manual specifies torque values and other parameters in specific units (e.g., inch-pounds, Newton-metres, lb-ft). The certifying staff must:

Use the specified units as stated in the approved data
Use tools calibrated in the same units as specified
Not convert units unless the approved data explicitly permits it

Rationale: Using a torque wrench with different units than specified introduces a risk of incorrect torque application. The approved data does not permit deviation from the specified units.

10.2 Tool Control

Part-145.A.40 requires that:

All tools and equipment are controlled and calibrated
Tools are appropriate for the tasks being performed
Calibration is current and traceable

11. International and National Regulatory Interfaces

11.1 Applicability to EU-Registered Aircraft

Part-145 applies to maintenance of EU-registered aircraft performed by EU Part-145 organisations. The release to service is governed by:

Part-145.A.50 (for Part-145 organisations)
Part-M.A.801 (for Part-M Subpart F organisations)

The operator's nationality does not change the regulatory basis for the maintenance organisation's certification. ICAO Annex 6 sets international standards but does not override EU regulations for EU-registered aircraft.

11.2 EASA Form 1

The EASA Form 1 is the certificate of release to service for components. It certifies that the component has been maintained in accordance with approved data and is airworthy.

12. Common Relationships Between Concepts

The following relationships are fundamental to understanding the regulatory framework:

Licence → Privileges → Responsibility

The Part-66 licence grants the privilege to certify maintenance
With this privilege comes the personal responsibility for the airworthiness of the aircraft
The licence may be revoked or suspended if the holder fails to meet the requirements

Approved Data → Maintenance Performance → CRS

Maintenance must be performed in accordance with approved data
The certifying staff member must verify compliance with approved data
Only then may a CRS be issued

Supervision → Control → Certification

Direct supervision provides control over the maintenance performed
Control is a prerequisite for certification
The certifying staff member must have sufficient oversight and assurance of the work's quality

Maintenance Programme → Approval → Compliance

The maintenance programme must be approved by the competent authority
Any changes require authority approval
Compliance with the programme is mandatory

Defect → Rectification → Release

Any defect that could affect safety must be rectified before release
Rectification must use approved data
Deferral is only possible with explicit approval

13. Typical Exam Focus Points

When preparing for the Module 10 examination, pay particular attention to the following areas:

13.1 Certifying Staff Responsibilities (High Priority)

The personal responsibility of the certifying staff member who signs a CRS
The conditions that must be met before issuing a CRS
The prohibition on signing a CRS for work not personally performed or directly supervised
The consequences of signing a CRS without proper authority

13.2 Licence Requirements (High Priority)

Minimum age: 18 years
Unlimited validity of the AML
Experience requirements: 6 months in the preceding 2 years
Suspension/revocation procedures: refresher training and examinations
B3 category scope: light helicopters and small non-complex aeroplanes

13.3 Supervision Requirements (High Priority)

Direct supervision requirements for unlicensed personnel
The difference between direct supervision and merely checking final results
The responsibility of the certifying staff for the quality of work performed under their supervision

13.4 Approved Data Compliance (High Priority)

The requirement to use approved data for all maintenance
The prohibition on deviating from specified units of measurement
The approval process for repairs not covered by approved data (Part-21)

13.5 Maintenance Programme Requirements (Medium Priority)

The approval process for maintenance programmes (Part-M.A.302)
The prohibition on unilateral changes to inspection intervals
The mandatory nature of airworthiness limitations

13.6 Occurrence Reporting (Medium Priority)

The obligation to report defects that could affect safe operation
The reporting channels (organisation's system, competent authority, quality manager)

13.7 Regulatory Hierarchy (Medium Priority)

The relationship between the Basic Regulation, implementing regulations, and AMC/GM
The specific regulation governing maintenance personnel licensing (Part-66)
The specific regulation governing maintenance organisations (Part-145)

13.8 Common Exam Traps

Signing a CRS for work not performed or supervised — always a violation
Using incorrect tools or units — not permitted unless explicitly allowed
Deferring defects without approval — not permitted
Extending maintenance intervals without authority approval — not permitted
Approving repair designs as certifying staff — not within the privileges of the licence
Assuming the licence has a fixed expiry date — the AML has unlimited validity
Assuming type ratings are not required for B3 — type ratings are required for specific aircraft types

14. Summary of Key Regulatory References

Regulation	Content	Relevance to B3
Regulation (EU) 2018/1139	Basic Regulation establishing EASA	Overarching legal framework
Regulation (EU) No 1321/2014, Annex I (Part-M)	Continuing airworthiness requirements	Owner responsibilities, maintenance programme, CAMO
Regulation (EU) No 1321/2014, Annex II (Part-145)	Maintenance organisation requirements	Personnel, certification of maintenance, tools, occurrence reporting
Regulation (EU) No 1321/2014, Annex III (Part-66)	Licensing of maintenance personnel	Licence requirements, privileges, experience, type ratings
Regulation (EU) No 748/2012, Part-21	Initial airworthiness	Approval of repairs and design changes

15. Conclusion

Module 10 establishes the legal and regulatory foundation for the professional practice of aircraft maintenance certifying staff. The B3 licence holder must understand not only the technical aspects of maintenance but also the legal framework that governs their work. The CRS is the central document that links the maintenance performed to the legal responsibility of the certifying staff member. Compliance with approved data, proper supervision of unlicensed personnel, and adherence to the maintenance programme are non-negotiable requirements.

The certifying staff member's signature on a CRS is a legal attestation of airworthiness that carries personal responsibility. Understanding the regulatory framework is not merely an academic exercise — it is essential for safe and lawful practice.