Sofema Online (SOL) www.sofemaonline.com considers the key features of an EASA Modification considering both Minor & Major

Introduction

The distinction between minor and major modifications in the EASA framework is a critical element of aircraft design and maintenance. Proper determination relies on a structured assessment by the DOA holder and adherence to EASA regulations.

Understanding and applying these principles ensures modifications are implemented safely and efficiently, preserving the aircraft's airworthiness and operational integrity. 

The determination of whether a modification is minor or major involves several steps, including:

Assessment by the Design Organization (DOA Holder)

Organizations holding a Design Organisation Approval (DOA) under EASA Part 21 are authorized to classify modifications.

• Minor Modifications: The DOA can classify and approve internally.

• Major Modifications: Must be submitted to EASA for review and approval.

Criteria for Classification
Key factors include:

• Impact on airworthiness: If the modification affects primary structures, flight controls, or systems critical to safety, it is likely major.

• Impact on performance: Changes to aerodynamic or engine performance may indicate a major modification.

• Impact on environmental characteristics: Alterations to noise or emission levels are scrutinized.

• Change in type-certificated data: If the modification deviates significantly from the approved type design, it may be classified as major.

Use of EASA Guidance Material
EASA's Guidance Material and Acceptable Means of Compliance provide specific examples and scenarios to aid in classification.

• Consultation with EASA
For complex or borderline cases, the DOA holder can consult EASA for clarification or determination of the Approval Process.

• Minor Modifications

>> Approved internally by the DOA.

>> The organization must document the modification and demonstrate compliance with applicable requirements.

>> The approved modification is entered into the aircraft's records.

• Major Modifications

>> The modification is submitted to EASA for approval.

>> EASA evaluates the modification's compliance with airworthiness and environmental standards.

>> Approval may include a Supplemental Type Certificate (STC) or an amendment to the Type Certificate.

Examples of Minor vs. Major Modifications

• Minor Modifications:

>> Installation of non-structural components (e.g., cabin signage, decorative panels).

>> Changes to avionics software that do not impact critical systems.

>> Replacement of components with equivalent parts.

• Major Modifications:

>> Structural alterations, such as modifications to wing or fuselage structures.

>> Changes to flight control systems.

>> Installation of new systems that require re-certification (e.g., new navigation or engine control systems).

Practical Considerations

• Risk Assessment
Always conduct a risk assessment to determine the potential impacts of the modification.

• Documentation
Maintain detailed records for traceability and future audits.

• Communication with Authorities
Proactive engagement with EASA ensures clarity and prevents delays in approval.

• Training and Competence
Ensure design and engineering staff are familiar with EASA regulations and classification criteria.

Next Steps

Sofema Aviation Services (SAS) and Sofema Online (SOL) provide classroom, webinar and regulatory training. Please see the following training course - AD, SB & Repair Considerations for EASA CAMO- 1 Day.

For comments or questions, please email team@sassofia.com.