5.1 Continuing Airworthiness Responsibilities & Part-M Scope

Regulatory Architecture: Regulation (EU) No 1321/2014 & Part-M Scope

Continuing airworthiness encompasses all of the processes ensuring that, at any time in its operating life, an aircraft complies with the airworthiness requirements in force and is in a condition for safe operation. Within the European regulatory architecture established under the EASA Basic Regulation (Regulation (EU) 2018/1139), continuing airworthiness is codified by Commission Regulation (EU) No 1321/2014.

Historically, Annex I (Part-M) applied universally to all civil aircraft operating within the European Union. However, following the landmark regulatory restructuring introduced by Regulation (EU) 2019/1383 and Regulation (EU) 2020/270, the European regulatory framework adopted a tiered, risk-proportionate structure. Light, non-commercial general aviation aircraft were transferred to Annex Vb (Part-ML), while continuing airworthiness management organisations were split into Annex Vc (Part-CAMO) for complex and commercial operations and Annex Vd (Part-CAO) for combined general aviation operations. Consequently, the contemporary scope of Annex I (Part-M) is precisely focused on:

1. Complex Motor-Powered Aircraft (CMPA): Irrespective of whether they are operated for commercial, specialized, or private non-commercial purposes.
2. Aircraft Operated by Licensed Air Carriers: All aircraft utilized in Commercial Air Transport (CAT) licensed under Regulation (EC) No 1008/2008.
3. Other-than-CMPA Not Governed by Part-ML: Aircraft outside the lightweight thresholds of Part-ML that are not managed under the simplified general aviation framework.

Statutory Definition of Complex Motor-Powered Aircraft (CMPA)

Pursuant to Article 3(31) of Regulation (EU) 2018/1139, an aircraft is classified as a Complex Motor-Powered Aircraft if it satisfies any of the following technical criteria:

• Aeroplanes:
  • Maximum certificated take-off mass (MTOM) exceeding 5,700 kg (12,566 lbs); or
  • Certificated for a maximum operational passenger seating configuration (MOPSC) of more than 19; or
  • Certificated for operation with a minimum flight crew of at least two pilots; or
  • Equipped with one or more turbojet (or turbofan) engines; or
  • Equipped with more than one turboprop engine (note: a single-engine turboprop with MTOM $\le$ 5,700 kg and $\le$ 19 seats is non-complex).
• Helicopters (Rotorcraft):
  • Certificated for a maximum take-off mass exceeding 3,175 kg; or
  • Certificated for a maximum passenger seating configuration of more than 9; or
  • Certificated for operation with a minimum crew of at least two pilots.
• Tilt-rotor aircraft: All powered-lift/tilt-rotor aircraft are automatically classified as CMPA.

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Division of Continuing Airworthiness Responsibilities: M.A.201

A central focus of EASA Part-66 Module 10 examinations is the statutory allocation of airworthiness responsibility under M.A.201. European law maintains an uncompromising boundary between ownership obligations, commercial operator liability, and maintenance organisation performance.

1. General Owner Responsibility (M.A.201(a))

Under M.A.201(a), the registered owner of an aircraft is fundamentally responsible for its continuing airworthiness. The owner must guarantee that:

• No flight takes place unless the aircraft is maintained in an airworthy condition;
• Any operational and emergency equipment fitted is correctly installed and serviceable or clearly identified as unserviceable;
• The Certificate of Airworthiness (CofA) and Airworthiness Review Certificate (ARC) remain valid;
• The maintenance of the aircraft is performed in accordance with the approved Aircraft Maintenance Programme (AMP) specified in M.A.302.

2. Operator Responsibility in Commercial Operations (M.A.201(e))

For Commercial Air Transport (CAT), the general owner rule is superseded. Under M.A.201(e), the air carrier licensed under Regulation (EC) No 1008/2008 (the AOC holder) is directly responsible for the continuing airworthiness of the aircraft it operates. The operator cannot contract away this primary statutory liability. To satisfy this legal obligation, an EU commercial air transport operator must:

• Take the necessary steps to be approved as a CAMO under Annex Vc (Part-CAMO) as part of the air operator certificate for the aircraft it operates (M.A.201(e)(2));
• Take the necessary steps to be approved under Annex II (Part-145), or conclude a written contract under CAMO.A.315(c) with an approved Part-145 organisation (M.A.201(e)(3));
• Note the derogation in M.A.201(ea): two or more operators forming part of a single air carrier business grouping may share one CAMO, subject to five conditions including a contract under Appendix I and harmonised management systems;
• Establish and maintain an approved Aircraft Technical Log system pursuant to M.A.306.

3. Commercial Specialised Operations and CMPA (M.A.201(f))

For commercial operations other than CAT (e.g. commercial aerial work, external sling load, aerial photography) or non-commercial operations of CMPA, the operator is responsible. The operator must either be approved as a Part-CAMO / Part-CAO, or establish a written contract with an approved CAMO / CAO in accordance with Appendix I to Part-M.

4. Leased Aircraft and Contracted CAMO Duties

When an aircraft is leased, the continuing airworthiness responsibilities transfer from the lessor to the lessee if the lessee is named on the registration document or if the lease agreement explicitly designates operational control to an AOC holder. When an owner contracts an approved CAMO via a formal Appendix I Continuing Airworthiness Agreement, the CAMO assumes full statutory responsibility for the proper accomplishment of continuing airworthiness management tasks, while the owner remains obligated to grant the CAMO full physical access to the aircraft and provide accurate technical log records without delay.

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Core Continuing Airworthiness Tasks: M.A.301

Regulation M.A.301 establishes the essential continuing airworthiness tasks that must be executed to ensure an aircraft remains safe to fly. Certifying engineers must understand the exact regulatory boundaries of each task:

1. Pre-Flight Inspection (M.A.301(a))

The pre-flight inspection is a functional walk-around verification that the aircraft is fit for the intended flight. Crucially for Part-66 licensing exams:

• It must be performed by the pilot-in-command or by a qualified individual (such as a trained flight crew member, ground technician, or handling agent) acting under the direct operational responsibility of the operator;
• It does NOT require a Certificate of Release to Service (CRS);
• It does not constitute maintenance under EASA Part-145 or Part-M;
• It includes verifying that external covers, control surface locks, and landing gear ground locking pins are removed, pitot-static probes are unobstructed, fuel drains have been tested for water contamination, and all structural access doors and cowlings are closed and secured.

2. Defect Rectification & Damage Management (M.A.301(b))

Any defect or damage affecting the safe operation of the aircraft must be rectified before further flight. Rectification must be conducted in strict accordance with approved maintenance data (such as the Aircraft Maintenance Manual (AMM), Structural Repair Manual (SRM), or engine shop manuals):

• Defect Deferral: If a defect cannot be immediately rectified prior to departure, it may only be deferred if permitted by the Minimum Equipment List (MEL) approved under Part-ORO.MLR.105 or the Configuration Deviation List (CDL). Deferred defects must be formally tracked in the Aircraft Technical Log;
• Damage Assessment: Structural damage exceeding allowable limits in the SRM must be repaired using approved design data issued by the Type Certificate (TC) holder or an approved Part-21 Design Organisation (DOA).

3. Execution of the Aircraft Maintenance Programme (M.A.301(c) & (e))

All maintenance must be accomplished in strict compliance with the approved Aircraft Maintenance Programme (AMP) referred to in M.A.302. This includes calendar, flight-hour, and cycle check packages. Additionally, under M.A.301(e), for all complex motor-powered aircraft and aircraft used by air carriers licensed under Regulation (EC) No 1008/2008, the effectiveness of the approved AMP must be analysed through an active reliability programme.

4. Mandatory Airworthiness Information (M.A.301(f))

Every aircraft must comply with mandatory safety directives issued by regulatory authorities. This comprises:

• Airworthiness Directives (ADs): Issued or adopted by EASA pursuant to Part-21.A.3B;
• Operational Directives: Operational mandates possessing continuing airworthiness impact (e.g. mandated TCAS 7.1 retrofit, ADS-B Out mandates, 8.33 kHz channel spacing);
• Continued Airworthiness Requirements: Specific inspection or modification mandates established directly by EASA;
• Measures Mandated by Competent Authorities: Immediate reaction safety measures mandated by the National Aviation Authority (NAA) of the State of Registry under emergency powers.

5. Modifications and Repairs (M.A.301(g))

Every modification and repair embodied on the aircraft must be accomplished in accordance with M.A.304, using data approved under Part-21 (e.g. Supplemental Type Certificates, EASA standard changes/repairs under CS-STAN, or approved major/minor change approvals).

6. Maintenance Release (M.A.301(d))

All completed maintenance must be released in accordance with Subpart H of Part-M through a formal Certificate of Release to Service (CRS). For complex motor-powered aircraft and aircraft operated in commercial air transport, maintenance must be performed and released by an approved Part-145 maintenance organisation.

7. Mass and Balance Statement (M.A.301(h))

The current mass and balance statement, reflecting the actual configuration of the aircraft, must be delivered to the pilot-in-command — or to the operator, in the case of air carriers licensed under Regulation (EC) No 1008/2008. Candidates routinely forget this task exists.

8. Maintenance Check Flights (M.A.301(i))

Where necessary, maintenance check flights form part of the continuing airworthiness tasks. This limb was added when EASA introduced dedicated maintenance check flight rules, and is the ninth and final item in M.A.301.

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Continuing Airworthiness Record System: M.A.305 & M.A.306

Maintenance actions are legally non-existent unless recorded with absolute traceability. Regulation M.A.305 establishes the technical record-keeping system, complemented by the Aircraft Technical Log system under M.A.306 for commercial operations.

Logbooks and Record Architecture (M.A.305)

The continuing airworthiness record system must record the complete operational and maintenance history of the airframe, engines, propellers, and components. The system comprises:

• Aircraft Logbook, Engine Logbook(s) or engine module log cards, and Propeller Logbook(s);
• Component Log Cards for any service life-limited components and critical assemblies;
• Detailed Maintenance Records: Complete work packages, job cards, task sign-offs, and associated EASA Form 1 Authorized Release Certificates issued by Part-145 or Part-21 organisations.

Required Continuous Status Summaries (M.A.305(d))

At any given moment, the continuing airworthiness management system must maintain an up-to-date summary of:

1. Total Operating Time: Cumulative flight hours, flight cycles, and calendar elapsed time for the aircraft and all installed engines, propellers, and life-limited components;
2. Compliance Status of Mandatory Information: Detailed AD status tracking current revision, implementation date, flight hours/cycles at compliance, method of compliance, and next repetitive inspection due date;
3. Modification and Repair Status: Comprehensive register of all embodied modifications and repairs, cross-referenced against the supporting Part-21 approval data (TC, STC, Minor Change, CS-STAN);
4. Status of AMP Compliance: Clear matrix showing current inspection status, flight hours/cycles accumulated since last check, and exact expiration thresholds for next scheduled tasks;
5. Life-Limited Parts (LLP) Status: Full historical record of each life-limited part, showing part number, serial number, total accumulated hours/cycles/calendar time, certified operating life limit, and remaining operating margin.

Aircraft Technical Log System (M.A.306)

For commercial air transport, commercial specialized operations, and commercial CMPA, the operator must utilize an approved Aircraft Technical Log system containing:

• General flight information (date, departure/arrival aerodrome, takeoff and landing times, accumulated block and flight hours, flight cycles);
• The current valid Certificate of Release to Service (CRS) covering the last maintenance work package or transit inspection;
• The current maintenance statement showing the next scheduled maintenance inspection due date and hours/cycles;
• All outstanding deferred defects and rectification discrepancies affecting aircraft operation, cross-referenced against the approved MEL;
• Necessary guidance instructions on maintenance support arrangements and operational sector limitations.

Record Retention Periods: M.A.305(e) & (h)

Record retention rules are heavily scrutinized in EASA Part-66 licensing examinations. The statutory retention windows are strictly defined:

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Practical Maintenance Scenario & Module 10 Exam Tips

Maintenance Practical Example: A Part-66 B1 certifying engineer performing a turnaround transit check on a Boeing 737-800 operated by an EU commercial airline discovers a chipped fan blade on Engine 1 that exceeds AMM visual limits. The line maintenance supervisor asks the engineer to "sign off a pre-flight inspection and let the captain fly back to home base where the CAMO can assess it." Under M.A.301(b) and M.A.201, the engineer must refuse. A defect exceeding AMM limits cannot be deferred unless covered by the approved MEL (which fan blade damage is not). Allowing flight violates M.A.301(b). Furthermore, a pre-flight inspection cannot be substituted for defect rectification, and releasing an aircraft with a known unairworthy defect constitutes a false release under Part-145.

Module 10 Exam Tips:

• Remember the boundary: M.A.201(a) places responsibility on the owner, M.A.201(b) transfers it to the lessee where the lease so provides, and M.A.201(e) places it on the AOC holder for CAT. M.A.201(ea) is only the business-grouping derogation.
• Pre-flight inspection under M.A.301(a) never requires a CRS and does not require a Part-66 licence.
• Memorize the retention numbers: 36 months (3 years) for detailed work cards, technical logs, and Form 1s; 12 months after permanent withdrawal from service for total time, LLPs, ADs, and modification/repair status.
• Complex motor-powered aircraft (CMPA) criteria: Aeroplane MTOM > 5,700 kg, or MOPSC > 19, or $\ge$ 2 pilots, or turbojet, or multiple turboprops.
• For CAT, the operator must be approved under Part-145 or hold a written contract with an approved Part-145 organisation (M.A.201(e)(3)).