Module 10: Aviation Legislation

Module 10: Aviation Legislation — Category B1.1 (EASA Part-66)

1. Module Overview

Module 10 of the EASA Part-66 basic knowledge syllabus provides the legislative foundation for aircraft maintenance certifying staff. For the B1.1 category (aeroplane turbine), this module covers the regulatory framework governing the continuing airworthiness of aircraft, the privileges and limitations of the aircraft maintenance licence (AML), and the obligations of maintenance organisations and certifying personnel.

This module is not about the technical execution of maintenance tasks—that is covered in other modules. Instead, it focuses on the legal and administrative environment in which maintenance is performed. A B1.1 certifying engineer must understand not only how to perform maintenance but also under what authority, using which data, and with what documentation the work is certified.

The primary regulatory reference is Regulation (EU) No 1321/2014, which consolidates the following Annexes:

Knowledge levels for this module range from Level 1 (overview of the regulatory framework) to Level 3 (detailed understanding of specific obligations, privileges, and procedures).

2. Key Concepts Explained in Detail

2.1 The Regulatory Hierarchy

The European aviation regulatory framework operates as a hierarchy:

For the certifying engineer, the most directly applicable document is Regulation (EU) No 1321/2014, specifically Part-66 (licensing) and Part-145 (maintenance organisation approval).

2.2 The Part-66 Aircraft Maintenance Licence (AML)

2.2.1 Categories of Licence

Part-66 defines the following licence categories:

Important distinction for B1.1: The B1.1 licence covers aeroplane turbine engines and associated systems. This includes engine removal and installation, engine-driven accessories, and the mechanical and electrical systems of the airframe. It does not include avionics systems (which fall under B2).

2.2.2 Eligibility Requirements for Licence Issue

Part-66.A.30 specifies the mandatory requirements for the initial issue of an AML:

2.2.3 Validity and Recency Requirements

The AML is issued without a fixed expiry date (Part-66.A.10). It remains valid indefinitely unless revoked, suspended, or limited by the competent authority. However, to exercise certification privileges, the holder must meet the following conditions (Part-66.A.20):

If these conditions are not met, the licence itself remains valid, but the holder cannot certify maintenance until the recency requirements are re-established.

2.2.4 Limited Licences

Part-66.A.30(b) permits the competent authority to issue a limited licence to an applicant who does not fully meet the experience requirements, provided they have at least 50% of the required experience. The limited licence is valid for a maximum of 3 years, after which it must be converted to a full licence.

2.2.5 Privileges of the B1.1 Licence

Part-66.A.20(a)(1) defines the privileges of a B1.1 licence holder:

Critical limitation: The B1.1 licence does not authorise maintenance on avionics systems (e.g., radio, navigation, instrument systems). These require a B2 licence. A B1.1 holder who performs avionics tasks is in violation of Part-66 and Part-145 requirements.

2.3 Part-145 Maintenance Organisations

2.3.1 Scope of Approval

Part-145.A.20 defines the scope of approval of a maintenance organisation. This scope specifies:

Key principle: A certifying engineer can only certify maintenance within the scope of the organisation that employs them. The individual's Part-66 licence does not override the organisational approval. If a Part-145 organisation is approved only for line maintenance, it cannot perform an engine change, even if the certifying staff hold the appropriate type rating.

2.3.2 Certifying Staff Requirements (Part-145.A.35)

Each Part-145 organisation must:

When a certifying engineer moves from one Part-145 organisation to another, their Part-66 licence remains valid and does not need to be reissued. However, the new organisation must include them in their MOE and verify that their type ratings are current.

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

The Certificate of Release to Service (CRS) is the document issued by certifying staff confirming that maintenance has been performed correctly and the aircraft is safe for return to service.

Fundamental rule: A CRS may only be issued for work that the certifying staff member has personally performed or directly supervised. Signing for work performed by others without supervision is a serious violation that can lead to revocation of the licence.

For components, the equivalent document is the EASA Form 1 (maintenance release). The CRS is for the aircraft; the EASA Form 1 is for components. They are not interchangeable.

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

All tools and equipment must be:

Using an out-of-calibration torque wrench, for example, is a non-compliance that could lead to incorrect torque application and potential component failure. The maintenance would not be considered properly performed, and the CRS could be invalid.

2.3.5 Required Inspection Items (RII)

Part-145.A.40 and AMC 145.A.40 require that certain tasks be designated as Required Inspection Items (RII). These are tasks where a mistake could have significant safety consequences. RII must be:

The organisation's MOE defines which tasks are RII and the procedures for their control. A certifying staff member who is not an RII holder for a specific task cannot sign off an RII, even if they performed the work.

2.4 Part-M Continuing Airworthiness

2.4.1 The Approved Maintenance Programme (AMP)

Part-M.A.302 requires that all aircraft, including those in non-commercial operations (Part-NCO), are maintained in accordance with an approved maintenance programme. The AMP must:

When a new AD is issued, the owner/operator must ensure that the AMP is updated to incorporate the AD's requirements.

2.4.2 The CAMO (Part-M Subpart G)

The Continuing Airworthiness Management Organisation (CAMO) is responsible for:

Important distinction: The CAMO does not perform maintenance itself. That is a Part-145 function. The CAMO manages; the Part-145 organisation executes.

2.4.3 Airworthiness Directives (ADs)

An AD is a mandatory airworthiness requirement issued when an unsafe condition exists. Key principles:

2.5 Approved Data (Part-145.A.45)

Maintenance must be performed using approved data. This includes:

Critical principle: A vendor service bulletin becomes approved data only when it is incorporated into the type certificate holder's instructions or the operator's maintenance programme. Using unapproved data is a violation of Part-145.

If damage is found that is not covered by the SRM or AMM (e.g., a crack in a structural member not listed as repairable), it cannot be repaired using a 'standard patch' without design approval. The certifying staff must not release the aircraft unless:

2.6 Part-21 Design Approvals

Part-21 governs the design and production of aeronautical products. Key concepts for the certifying engineer:

This is a key distinction between maintenance (restoring to an approved condition) and design (changing the approved condition).

2.7 Part-147 Training Organisations

Part-147 governs the approval of maintenance training organisations. Key points:

3. Important Regulations and Procedures

3.1 Key Part-66 References

3.2 Key Part-145 References

3.3 Key Part-M References

3.4 Key Part-21 References

4. Common Relationships Between Concepts

4.1 The Certification Chain

The relationship between the key actors can be summarised as:

Part-21 (Design/Production)

↓ provides approved data and airworthy parts

Part-M (Continuing Airworthiness Management)

↓ defines what maintenance is required (AMP, ADs)

Part-145 (Maintenance Organisation)

↓ performs maintenance using approved data

Part-66 (Certifying Staff)

↓ issue CRS confirming work correctly performed

Aircraft released to service

4.2 Licence vs. Organisation Scope

A common source of confusion is the relationship between the individual licence and the organisational approval:

4.3 AD Compliance and the CRS

The relationship between ADs and certification:

4.4 Approved Data and Airworthiness

The relationship between data and airworthiness:

5. Typical Exam Focus Points

Based on the source questions, the following areas are frequently examined:

5.1 Licence Eligibility and Validity

5.2 Licence Privileges and Limitations

5.3 Certification Obligations

5.4 Organisational Requirements

5.5 Design vs. Maintenance

5.6 Regulatory Structure

6. Summary of Key Principles for the B1.1 Certifying Engineer

7. Conclusion

Module 10 provides the legal framework within which all maintenance activities must operate. For the B1.1 certifying engineer, mastery of this module is not merely an examination requirement—it is essential for safe and lawful practice. The regulations are designed to ensure that every aircraft released to service is airworthy, that every maintenance task is properly documented, and that every certifying staff member acts within their authority.

The recurring themes are authority (who may do what), data (what may be used), documentation (what must be recorded), and compliance (what must be accomplished). Understanding these four themes and their interrelationships is the key to both passing the examination and practising safely as a certifying engineer.