Part 145 Approval & Set-Up

Approval, Compliance & Safety Advisory for EASA Part 145 & UK Part 145 Approved Maintenance Organisations

Achieving and maintaining a Part 145 Approved Maintenance Organisation approval is one of the most documentation-intensive and procedurally demanding regulatory processes in aviation. The competent authority examines not only whether the applicant has produced the correct documents but whether those documents accurately describe an organisation that is genuinely capable of performing the maintenance it is seeking approval for. An MOE that is well written but does not reflect how the organisation actually works will not survive authority scrutiny — and an approval built on inaccurate documentation creates compliance risk from the first day it is granted.

Aerospace and Aviation Consulting Services (AACS) provides specialist regulatory, compliance and safety advisory to Approved Maintenance Organisations operating under EASA Part 145, UK Part 145, and equivalent national airworthiness frameworks. Our advisory covers the full AMO lifecycle — from initial approval application and Maintenance Organisation Exposition development through to ongoing compliance management, Safety Management System implementation, Human Factors programme design, and preparation for authority oversight. We support line maintenance organisations, base maintenance facilities, component shops and avionics workshops across both commercial and general aviation sectors.

Part 145 Approved Maintenance Organisations operate within a regulatory framework that is technically demanding, procedurally detailed, and subject to regular revision. AACS operates across the full scope of this framework for both EASA and UK Part 145 approval holders.

Part 145 Approval & Initial Certification

Achieving Part 145 approval is a complex regulatory process that demands precise documentation, structured engagement with the competent authority, and a thorough understanding of the specific requirements applicable to the scope of work sought. The approval class and rating structure — Class A (aircraft), Class B (engines), Class C (components) and Class D (specialist services) — each carry distinct documentation, personnel, facilities and tooling requirements. Getting the scope definition right at the outset determines the entire shape of the application.

AACS supports organisations through every stage of the Part 145 approval process, from initial feasibility assessment through to the grant of approval and transition into operational compliance.

Services include:

• Part 145 approval scope definition and capability assessment — defining the approval class, ratings and limitations sought and confirming the organisation has the personnel, facilities and tooling to support them
• Pre-application gap analysis against EASA Part 145 / UK Part 145 requirements — identifying what the organisation has in place and what needs to be built before the first submission
• Maintenance Organisation Exposition (MOE) initial development — Parts 0 through 4, written for the specific organisation and its intended scope of approval
• Competent authority pre-application meeting preparation and support — preparing the Accountable Manager and key personnel for the pre-application engagement that establishes the relationship with the authority
• Certifying staff and support staff qualification and authorisation framework design — confirming that proposed certifying staff meet the Part 66 licence, type training and experience requirements for the ratings sought
• Facilities, tooling and equipment compliance assessment — reviewing the physical environment against Part 145 requirements for the approval scope
• Contracted maintenance and supplier control framework establishment — the procedures and supplier approval framework required before subcontracting maintenance to third parties
• Approval class and rating advisory — A (aircraft line and base), B (engines), C (components), D (specialist services including NDT, welding and avionics)
• Authority comment and finding response management — drafting responses to authority queries and managing revision cycles through to approval grant

Maintenance Organisation Exposition (MOE) Development & Revision

The Maintenance Organisation Exposition is the defining document of a Part 145 organisation. For the competent authority, it is the evidence that the AMO understands its obligations and has the procedures in place to discharge them. For the maintenance engineers and certifying staff who use it every day, it is the operational reference for how the organisation conducts its approved activities. A well-constructed MOE satisfies the authority and functions as a genuine operational tool. A poorly constructed one — whether inaccurate, incomplete or built on a generic template — fails both tests.

The four-part MOE structure and content developed by AACS:

MOE services include:

• Full MOE development for initial Part 145 approval — EASA Part 145, UK Part 145 and national authority equivalents
• MOE revision to reflect scope changes — new aircraft type ratings, additional component capabilities, new base or line stations, changes to the certifying staff establishment
• MOE upgrade following regulatory change — EASA regulatory revisions, UK CAA post-Brexit Part 145 amendments, AMC/GM updates
• MOE gap analysis ahead of authority oversight audit — identifying procedural deficiencies and documentation inaccuracies before they become findings
• Contracted maintenance and supplier control procedures development
• Certifying staff authorisation framework documentation — authorisation scope, limitations, continuation training requirements and record-keeping
• Technical records management and airworthiness data control procedures
• Part 21 Subpart G / Part-CAMO interface procedures development
• Authority finding response support and corrective action plan preparation
• Document control system design for MOE revision management

Compliance Monitoring & Quality System Design

An effective compliance monitoring system is a regulatory requirement under Part 145.A.65 and a fundamental safeguard of airworthiness. The compliance monitoring function must be independent of the maintenance it audits, structured to identify systemic risk rather than generate audit records, and capable of producing corrective action that addresses root causes rather than surface manifestations of compliance failure. In practice, the compliance monitoring systems of many AMOs — particularly smaller organisations without dedicated quality resource — are either inadequate in scope or have been established at approval and not meaningfully reviewed since.

AACS designs and implements compliance monitoring frameworks that satisfy authority requirements while providing genuine operational assurance.

Services include:

• Compliance monitoring system design aligned with Part 145.A.65 requirements — independence, scope, methodology and reporting
• Internal audit programme development — annual schedule, audit scope, methodology and reporting framework
• Audit checklist development calibrated to the AMO’s specific approval scope, aircraft types and maintenance activities — not generic Part 145 checklists
• Finding classification, corrective action and root cause analysis framework — the process through which compliance findings are assessed, assigned corrective action and tracked to verified closure
• Accountable Manager and Quality Manager briefing and advisory support
• Independent compliance audit — external assessment of the AMO’s compliance position ahead of authority oversight, identifying what an authority inspector would find before they find it
• Supplier and contracted organisation audit programme design
• Authority finding response support and corrective action plan preparation
• Preparation for EASA, UK CAA and national authority oversight audits

Safety Management System for Part 145 Organisations

The requirement for Part 145 organisations to implement a Safety Management System under Part 145.A.200 reflects the regulatory recognition that proactive safety management is as important in maintenance as it is in flight operations. For an AMO, the SMS must address the specific hazard profile of the maintenance environment: maintenance error, task interruption, shift handover risk, fatigue in night shift and extended maintenance tasks, inadequate maintenance data, and the systemic organisational conditions that produce maintenance-related airworthiness failures.

AACS designs and implements SMS frameworks specifically tailored to the AMO environment — building systems that surface latent organisational conditions and systemic risks, rather than simply collecting occurrence reports.

Services include:

• SMS framework design aligned with ICAO Annex 19 and Part 145.A.200 requirements — proportionate to the AMO’s size and scope
• Hazard identification and maintenance risk assessment processes — calibrated to the specific maintenance activities, aircraft types and working environment of the AMO
• Safety Performance Indicator (SPI) development for maintenance environments — maintenance error rates, task interruption frequency, defect recurrence, near miss reporting rates
• Occurrence reporting system design and just culture policy development — building a reporting culture in which engineers submit reports without fear of disproportionate consequence
• Maintenance error investigation methodology — HFACS, TapRoot and Maintenance Error Decision Aid (MEDA) processes for structured investigation of maintenance errors
• Safety review board structure and governance documentation
• SMS integration with the compliance monitoring system — ensuring that compliance findings are treated as safety data and feed into the SMS improvement cycle
• Safety culture assessment and Human Factors programme development
• SMS maturity evaluation and improvement roadmap

Human Factors & Maintenance Error Management

Human performance is the single largest contributor to maintenance errors. The ICAO and UK CAA accident investigation record is unambiguous: the majority of maintenance-related airworthiness failures that contribute to accidents and serious incidents trace back to human error produced by systemic organisational conditions — inadequate procedures, task interruption, ineffective shift handover, fatigue, tool and parts control failures, and the normalisation of deviation from documented procedure. Addressing these conditions requires more than mandated Human Factors training. It requires a structured understanding of how human performance in the specific maintenance environment fails, and why.

AACS provides specialist Human Factors advisory and training to Part 145 organisations seeking to reduce maintenance-related airworthiness risk through operationally grounded human performance analysis.

Services include:

• Human Factors programme design aligned with Part 145.A.30 and AMC 145.A.30(e) — initial and continuation training requirements for all personnel involved in licensed maintenance
• Maintenance Error Decision Aid (MEDA) investigation process implementation — structured methodology for investigating maintenance errors and identifying the contributing factors that produced them
• Error-likely conditions analysis and mitigation strategy development — identifying the specific situational, environmental and organisational factors in the AMO that create conditions for maintenance error
• Shift handover risk assessment and procedure design — one of the highest-risk transitions in maintenance operations, consistently identified in accident investigations
• Task card design and work instruction review — assessing whether documented task instructions support error-free task performance or create error traps
• Work environment risk assessment — lighting, noise, access, tooling and parts control in the context of human performance
• Human Factors training programme design and delivery for certifying staff — built around the specific maintenance environment, not generic awareness content
• Fatigue risk assessment and shift pattern review for maintenance operations — night shift, extended maintenance tasks, on-call working and the fatigue risk profile of the AMO’s working patterns
• Continuation training programme design incorporating Human Factors content — structured to meet the Part 145.A.35 continuation training requirement
• Human Factors audit of maintenance procedures and documentation — assessing whether the AMO’s procedures support or undermine safe human performance

Approval Scope Extension & New Rating Advisory

Established AMOs regularly seek to extend their approval scope — to add new aircraft type ratings, to expand from line to base maintenance capability, to add component or avionics workshop capabilities, or to obtain specialist service approvals including NDT, welding and composite repair. Each scope extension requires a formal application to the competent authority, with corresponding MOE amendments, a demonstration that the AMO has the certifying staff, facilities, tooling and procedures to support the new scope, and in some cases the completion of a capability demonstration to the authority’s satisfaction.

Services include:

• Scope extension assessment — confirming what the extension requires in terms of regulatory demonstrations, personnel qualifications, facilities and documentation
• New aircraft type rating application support — certifying staff type training requirements, tooling and equipment assessment, MOE amendment and authority engagement
• Base maintenance capability development — moving from line to base maintenance approval; the additional requirements for hangar facilities, specialised tooling and base maintenance procedures
• Component and avionics workshop approval advisory — Class C and Class D approval requirements, component acceptance procedures, test equipment calibration frameworks
• NDT approval application support — qualification requirements for NDT personnel, equipment standards, procedure documentation and authority demonstration requirements
• MOE amendment preparation — revising all affected MOE sections to reflect the new scope accurately
• Certifying staff authorisation scope amendment — updating authorisations to reflect the new type ratings or capabilities
• Authority application submission and engagement through to scope approval

Authority Oversight Preparation & Finding Response

EASA and UK CAA oversight visits are the primary mechanism through which the authority assesses whether an AMO is operating in compliance with its approval conditions. Preparation for oversight is not merely a documentation exercise — it is the opportunity to identify the gaps that the authority would otherwise find, to confirm that the MOE accurately reflects how the organisation conducts maintenance, and to ensure that the Accountable Manager and Quality Manager are prepared to present the organisation’s compliance position credibly and accurately.

Services include:

• Pre-oversight compliance gap analysis — independent assessment of the AMO’s compliance position against the areas the authority typically examines at oversight: certifying staff authorisations, maintenance data control, compliance monitoring records, SMS documentation, technical records
• MOE accuracy audit — confirming that the MOE accurately describes how the AMO currently operates, identifying any divergence between documentation and practice
• Certifying staff authorisation review — confirming that all certifying staff hold valid Part 66 licences, current type training, and authorisations correctly scoped to the work they certify
• Technical records compliance review — assessing whether maintenance records, worksheets and certificates of release to service meet the Part 145.A.55 standard
• Inspector engagement preparation — preparing the Accountable Manager and Quality Manager for the authority’s questions and the oversight process
• Finding analysis — understanding the root cause of each authority finding: documentation failure, operational divergence, training deficit or systemic compliance management weakness
• Corrective action plan development — addressing root causes rather than surface manifestations, with clear actions, ownership and timescales
• Authority finding response drafting — formal written responses presented at the level of detail and in the format the authority expects
• Post-corrective action verification — independently confirming that corrective actions have been implemented as described before the authority’s follow-up assessment

ISO 9001 Quality Management for AMOs

Many Part 145 organisations seek ISO 9001:2015 certification to complement their Part 145 compliance framework, satisfy airline customer requirements, support tenders for commercial maintenance contracts, or meet the expectations of CAMO principals and aircraft lessors. The challenge is implementing ISO 9001 in a way that integrates with the existing Part 145 compliance monitoring structure rather than duplicating it — because duplication creates administrative burden without generating quality or compliance benefit.

Services include:

• ISO 9001:2015 QMS design and implementation for Part 145 organisations — built around the existing compliance monitoring and MOE framework
• Integration of ISO 9001 processes with Part 145 compliance monitoring requirements — a single audit programme addressing both standards rather than parallel systems
• Quality manual and documented procedures development
• Process mapping, risk and opportunity assessment for maintenance operations
• Internal audit programme aligned with both ISO 9001 and Part 145 requirements
• Management review framework and continual improvement system design
• Preparation for third-party ISO 9001 certification audits
• Combined ISO 9001 / ISO 45001 (Occupational Health & Safety) integrated system advisory

Our Advisory Philosophy for Part 145 Organisations

AACS approaches Part 145 advisory with a clear conviction: airworthiness is not an administrative outcome. It is the product of a disciplined organisation, well-designed systems, and a workforce that understands why the procedures exist and follows them because they understand their purpose — not merely because a checklist requires it. Every element of our Part 145 advisory is built around this conviction.

✔  Part 145 approval must be built on procedures that reflect how the organisation actually works — not documentation produced to satisfy the authority that diverges from operational practice on day one

✔  Compliance monitoring must identify and correct systemic issues before they become authority findings — not generate audit records that satisfy the paperwork requirement without producing genuine assurance

✔  Safety Management Systems in maintenance must address human performance and the organisational conditions that produce error — not just collect occurrence reports

✔  MOE documentation must be accurate, current and usable — not a static approval artefact that describes how the organisation operated at the point of approval and has not been touched since

✔  Human Factors programmes must be operationally specific to the maintenance environment — not generic awareness training that satisfies the regulatory interval without changing how engineers approach their work

✔  ISO 9001 and Part 145 compliance monitoring should be integrated into one coherent framework — not maintained as separate administrative burdens that duplicate effort without delivering additional assurance

✔  Authority finding responses must address root causes — a finding response that changes a document without investigating why the document was wrong defers the compliance risk without resolving it

We deliver advisory that is independently verified, operationally credible, and built on over 30 years of real-world aviation maintenance regulatory expertise. Every engagement is structured around the specific AMO, its approval scope, its certifying staff, its maintenance environment and the specific compliance challenge it is facing — not a generic Part 145 advisory programme applied regardless of the operational reality.

Speak to an AACS Specialist

If you are seeking initial Part 145 approval, extending an existing scope, managing an authority finding, or seeking to strengthen your MOE, compliance monitoring, SMS or Human Factors programme, please contact us to discuss your requirements.