Every organisation approved under EASA Part-145 to carry out aircraft maintenance must hold a Maintenance Organisation Exposition — universally known as an MOE. The MOE is the primary regulatory document for the organisation: a comprehensive description of its scope, structure, procedures, and quality framework that forms the basis of its approval and against which it is audited by the national aviation authority.
For quality and compliance professionals, the MOE is a daily working document. For operational maintenance engineers, it is often less visible — but it underpins every approved procedure they follow. Understanding what the MOE contains and why it matters is useful knowledge for anyone working in a Part-145 environment.
The Structure of an MOE
The structure of a Part-145 MOE is defined by the regulation. EASA specifies the required sections, ensuring consistency across organisations, though the content within each section reflects the specific characteristics of the individual organisation. The main parts of an MOE are:
Part 0 – General Information — Corporate information, the scope of approval, the list of approved locations, and the amendment record.
Part 1 – Management — The organisational chart, the names and responsibilities of the Accountable Manager and key senior personnel (Post Holders), the procedures for ensuring compliance, and the financial soundness policy.
Part 2 – Maintenance Procedures — The core of the MOE. Part 2 contains the approved procedures covering all aspects of maintenance activity: acceptance of aircraft, maintenance documentation, technical standards, tool and equipment calibration, material control, manufacturing of parts, maintenance of components, release to service, and much more. This section may run to hundreds of pages in a large organisation.
Part 3 – Quality System Procedures — The procedures governing the quality monitoring and audit system, corrective action management, and the mechanics of how the quality function operates.
Part 4 – Contracted Maintenance and Sub-Contractors — Procedures for managing contracted maintenance activities and oversight of sub-contractors.
Appendices — Supporting lists and schedules, including the list of Sub-Part B (facilities), Sub-Part C (personnel), and approval details.
Keeping the MOE Current
The MOE is not a static document. It must be amended whenever the organisation’s approved procedures change, whenever key personnel change, whenever the scope of approval is extended or reduced, and whenever regulatory changes require procedural updates. Amendments must be agreed with the competent authority (national aviation authority) before implementation.
Managing the amendment process — ensuring that changes are properly reviewed, approved, and communicated across the organisation — is a significant part of the quality function’s workload. In large organisations, the MOE may be amended dozens of times a year.
Why the MOE Matters on the Hangar Floor
For engineers working in a Part-145 organisation, the MOE matters because it defines the approved procedures they are required to follow. Deviation from approved procedures — whether through ignorance, shortcut, or wilful non-compliance — represents a breach of the organisation’s approval and, potentially, a serious safety risk.
Understanding that the procedures exist within a regulatory framework — that they are approved by the national authority and not just management preferences — helps engineers appreciate why adherence to them is non-negotiable. The MOE is, ultimately, a contract between the organisation and its approval authority on behalf of the flying public.
Protec Technical places quality and compliance professionals, maintenance managers, and technical staff across the Part-145 environment. Contact our team to discuss your requirements.
