5.3 Airworthiness Review Certificate (ARC) & Review Procedures

Purpose and Legal Role of the Airworthiness Review Certificate

Under European civil aviation law (Regulation (EU) 2018/1139 and Regulation (EU) No 748/2012 Part-21), an individual aircraft is initially issued a Certificate of Airworthiness (CofA) (EASA Form 25). Unlike historical national certificates that expired annually, an EASA Certificate of Airworthiness is issued with unlimited duration. However, this unlimited validity is subject to a vital statutory condition: the CofA remains legally valid only if the aircraft satisfies all continuing airworthiness requirements, which is formally evidenced by a valid Airworthiness Review Certificate (ARC).

Pursuant to M.A.902(a) (and ML.A.902 for Part-ML aircraft), an Airworthiness Review Certificate is valid for 1 year. Without a valid ARC, the aircraft's Certificate of Airworthiness becomes automatically invalid, and any flight conducted without a valid ARC constitutes an illegal operation in violation of both European safety regulations and the 1944 Chicago Convention.

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Types of ARC Forms: Form 15a, 15b, and 15c

EASA regulations establish three distinct standardized administrative forms for Airworthiness Review Certificates, reflecting different regulatory scopes and issuing authorities:

1. EASA Form 15a

Issued exclusively by the Competent National Aviation Authority (NAA) of the Member State of Registry. Form 15a is issued under the following circumstances:

• When the NAA conducts the complete airworthiness review itself using its own airworthiness inspectors;
• When an approved Part-CAMO or Part-CAO conducts an airworthiness review and submits a formal Airworthiness Review Recommendation to the NAA (e.g. when the conditions of M.A.901(b)(1) are not met, or the organisation lacks airworthiness review privileges);
• When an aircraft is being imported from a third country onto the civil aircraft register of an EU Member State.

2. EASA Form 15b

Issued directly by an organisation approved to carry out airworthiness reviews under CAMO.A.125(e) of Part-CAMO or CAO.A.095(c)(1) of Part-CAO, where the three conditions of M.A.901(b)(1) are satisfied: continuing airworthiness continuously managed under M.A.201 (or ML.A.201) since the previous ARC was issued; the aircraft maintained in accordance with the Regulation since that issue; and the airworthiness certificate issued under Regulation (EU) No 748/2012 and not revoked or surrendered at the time of the review.

3. EASA Form 15c

Introduced under Annex Vb (Part-ML) for light aircraft (aeroplanes $\le$ 2,730 kg MTOM, rotorcraft $\le$ 1,200 kg MTOM, sailplanes, and balloons). Form 15c may be issued by the Competent Authority, an approved CAMO, a Combined Airworthiness Organisation (Part-CAO), or by an independent Part-66 certifying staff holding specific authorization under ML.A.901(b)(4).

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The Dual Airworthiness Review Process: M.A.903

To issue an Airworthiness Review Certificate (or submit an approval recommendation to the NAA), an organisation must execute a comprehensive, two-part examination of the aircraft: a full documented review and a physical survey.

1. The Full Documented Review

Authorized airworthiness review staff must audit the entire technical history of the aircraft to verify absolute regulatory conformity. The audit must establish that:

1. Airframe, Engine, and Propeller Operating Hours & Cycles: Have been accurately logged in the technical logbook and continuing airworthiness record system;
2. Flight Manual (AFM): Is current to the latest approved revision, including all applicable operational supplements and configuration limits;
3. Aircraft Maintenance Programme (AMP): All scheduled maintenance tasks have been accomplished strictly in accordance with the approved AMP;
4. Defect Rectification: All known defects have been rectified in accordance with approved data, or properly deferred in compliance with the approved Minimum Equipment List (MEL) and within allowable rectification intervals;
5. Airworthiness Directives (ADs): All applicable mandatory ADs have been fully complied with, verified, and correctly recorded with exact compliance status (including method of compliance and recurring due dates);
6. Modifications and Repairs: All embodied modifications and repairs have been recorded and proven compliant with Part-21 approved data (TC, STC, Major/Minor change approval, CS-STAN);
7. Life-Limited Parts (LLP): All service life-limited components and engine rotating discs are correctly identified, logged, and remain within their certified operating limits;
8. Maintenance Release Traceability: All maintenance has been released to service by an approved maintenance organisation (Part-145) with valid Certificates of Release to Service (CRS) and EASA Form 1 certificates;
9. Mass and Balance Statement: Is current, reflects the actual physical cabin and avionic configuration of the aircraft, and complies with operational weighing intervals;
10. Type Design Conformity: The aircraft complies with the latest revision of its approved type design.

2. The Physical Survey of the Aircraft

The documentary audit alone is insufficient. Authorized airworthiness review staff must physically inspect the aircraft to ensure reality matches documentation. The physical survey must verify that:

• All required external and internal markings, emergency placards, and registration signs are correctly installed, visible, and legible in the mandated languages;
• The physical configuration of installed engines, propellers, avionics boxes, emergency locator transmitters (ELTs), and safety equipment matches approved records;
• The aircraft is free of any evident defects, unapproved structural repairs, or unaddressed damage exceeding allowable limits;
• No evident fluid leaks (fuel, hydraulic fluid, engine oil) exist;
• No structural corrosion or structural chafing exists that has not been evaluated under Part-M;
• If deemed necessary by the airworthiness review staff, a test flight or ground functional test of specific systems may be mandated to verify flight handling or system integrity.

The 90-Day Anticipation Window

Under M.A.901(f), by derogation from M.A.902(a), the airworthiness review may be carried out 90 days or less before the expiry date of the ARC without loss of continuity of the airworthiness review pattern. If the review is successfully performed within this 90-day window, the new ARC validity terminates exactly 12 months from the previous certificate's expiration date, protecting the operator from administrative loss of operational time.

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Extension Conditions under M.A.902(b)

ARC extension is one of the most frequently tested topics in EASA Part-66 Module 10 examinations. It reflects an operational state where an aircraft's continuing airworthiness has been under uninterrupted, verified professional oversight since the certificate was issued.

Watch the terminology: "controlled environment" is legacy wording

Older textbooks describe a "controlled environment" defined in M.A.901(c). Commission Implementing Regulation (EU) 2026/100 rewrote Part-M Subpart I, and the current text no longer uses that phrase. The extension conditions now sit in M.A.902(b), and an ARC may only be extended by the organisation managing the continuing airworthiness of the aircraft, subject to all three of the following:

1. the continuing airworthiness of the aircraft has been continuously managed by that organisation since the issue of the ARC;
2. the aircraft has been maintained since the issue of the ARC by an organisation approved under Annex II (Part-145) or Annex Vd (Part-CAO), as applicable — note that Part-CAO now counts, and that this maintenance may include pilot-owner maintenance tasks carried out and released either by the pilot-owner or by independent certifying staff; and
3. the managing organisation has no evidence or reason to believe that the aircraft is not airworthy.

The reference period is measured from the issue of the ARC, not as a fixed "previous 12 months".

ARC Extension Privileges (M.A.902(a) and (b))

M.A.902(a) states that an ARC shall be valid for 1 year and its validity may be extended for another year for a maximum of two consecutive extensions. Only the organisation managing the continuing airworthiness of the aircraft may extend it, and only where the three M.A.902(b) conditions are met.

When the extension takes effect also matters:

• if the extension is carried out within 30 days before the expiry date, or after the expiry date, the extension begins on the previous expiry date;
• if the extension is carried out more than 30 days before the expiry date, it begins on the date the extension is carried out — so extending very early simply loses time.

After two consecutive extensions no further extension is possible: a fresh airworthiness review under M.A.903 (documented review plus physical survey) is required.

Two further practical rules: a copy of any ARC issued or extended must be sent to the competent authority of the Member State of registry within 10 days (M.A.901(i)); and the airworthiness review shall not be subcontracted (M.A.901(g)).

When the M.A.902(b) Conditions Fail

If the aircraft is maintained by an entity that is not approved under Part-145 or Part-CAO, or if continuous management by the same organisation is broken since the ARC was issued, the extension conditions are not met and the ARC cannot be extended. Under M.A.901(b), a satisfactory airworthiness review then results either in an ARC on EASA Form 15b where the conditions in M.A.901(b)(1) are met, or in a recommendation to the competent authority for the issue of an ARC where they are not — in which case the authority issues EASA Form 15a. An ARC shall not be issued at all if there is evidence or indication that the aircraft is not airworthy (M.A.901(h)).

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Importation of Aircraft from Third Countries

When an aircraft registered in a non-EU third country (such as the United States, Canada, or the UK) is imported onto the civil aircraft register of an EU Member State, strict airworthiness import procedures apply under Part-21 and Part-M (M.A.904):

1. Design Certification Verification: EASA verifies that the aircraft conforms to an EASA Type Certificate Data Sheet (TCDS);
2. Full Airworthiness Review: An approved Part-CAMO carries out a comprehensive documentary review of the aircraft's entire historical records from manufacture, alongside an exhaustive physical survey;
3. Bridging Maintenance: The CAMO establishes a bridging programme to reconcile maintenance intervals and ensure the aircraft satisfies the importing Member State's approved AMP, ALS limits, and mandatory EU operational equipment requirements (e.g. 8.33 kHz radios, Mode S, TCAS II version 7.1);
4. Recommendation to the Authority: The CAMO does not issue a Form 15b upon import. Instead, the CAMO submits a formal Airworthiness Review Recommendation to the Competent National Aviation Authority of the Member State of Registry;
5. Authority Issuance: The Competent Authority reviews the recommendation, conducts its own survey if deemed necessary, and directly issues the initial EASA Form 15a alongside the new Certificate of Airworthiness.

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Practical Maintenance Scenario & Module 10 Exam Tips

Maintenance Practical Example: An Airbus A330 has been continuously managed by an EU airline's CAMO for two years and maintained throughout by approved Part-145 organisations, having received its initial Form 15b and one annual extension. The aircraft is due for its second extension. Two weeks before the extension date, the airline contracts an emergency unapproved third-party mechanic at an overseas non-EU outstation to replace an avionics cooling blower motor without a Part-145 CRS. When the CAMO audits the technical log, it discovers the unapproved release. Because that maintenance was not performed by an organisation approved under Part-145 or Part-CAO, condition (2) of M.A.902(b) is broken. The CAMO cannot issue the second extension. The aircraft must undergo corrective maintenance by an approved Part-145 organisation and a full airworthiness review must be performed.

Module 10 Exam Tips:

• The CofA is valid indefinitely, provided the ARC remains valid.
• An ARC is valid for 1 year (12 months).
• Form 15a is issued by the Competent Authority (NAA); Form 15b is issued by an approved Part-CAMO; Form 15c is for Part-ML.
• Extension under M.A.902(b) requires: continuous management by that same organisation since the ARC was issued, maintenance since then by a Part-145 or Part-CAO organisation, and no reason to believe the aircraft is unairworthy. The phrase "controlled environment" was removed from Part-M by Regulation (EU) 2026/100.
• An ARC can be extended for a further year twice consecutively (maximum 3 years total between reviews).
• The airworthiness review may be carried out up to 90 days before the ARC expiry without losing continuity (M.A.901(f)).
• A copy of every ARC issued or extended goes to the competent authority of the State of registry within 10 days (M.A.901(i)), and the review cannot be subcontracted (M.A.901(g)).