AD/ATR 42/1 - State of Design Airworthiness Directives

The Directive rests on a small set of control concepts that determine legal effect and operational impact.

• State-of-Design Airworthiness Directives listed in Table 1 and Table 2. The Directive reproduces identifiers, issue dates and titles for DGAC ADs (Table 1) and EASA ADs (Table 2). It does not restate the remedial requirements of those foreign ADs in the body of the Directive, rather it directs operators to determine applicability and, where required, to perform the foreign-AD actions.

• Applicability determination. The Directive requires a fact-specific determination whether each listed DGAC or EASA AD applies to a particular ATR 42 airframe, taking into account manufacture date, configuration and modification status. The Directive emphasises that not all listed ADs will be applicable to all ATR 42 series aeroplanes, due to differences in those attributes (see Background).

• "Previously accomplished" qualifier. The Directive imposes obligations only where an applicable DGAC or EASA AD "has not been previously accomplished". The compliance duty therefore includes a records-check function, and potentially a burden of proof to show prior compliance.

• Compliance timeframe tied to effective date and Certificate of Airworthiness. The Directive specifies a two-part compliance trigger: operators must comply within 30 days after the Directive’s effective date, or before the issue of a Certificate of Airworthiness for the aircraft, whichever occurs first. That places a short window on operators and adds a hard deadline tied to the administrative step of CAO issuance.

• One-time actions. The Background states that the listed State-of-Design ADs "require one time actions for which the compliance date and/or period has passed." That characterisation matters for cost and workload, because one-time actions typically involve inspections, retrofits, parts replacement, or configuration changes that will not create recurring maintenance tasks but may involve immediate labour or parts costs.

• Referral to source AD texts. The Directive points operators to the original AD sources, providing URLs for EASA and DGAC AD databases. The substantive technical instructions, required parts, testing or inspections are contained in those ADs, not in the CASA Directive.

• Delegated issuance. The Directive is signed by a CASA delegate, indicating issuance under CASA authority. The body of the Directive is compact, concentrating legal force on the applicability-check obligation and the performance obligation for outstanding items.

These concepts together create an obligation chain: identify which of the listed foreign ADs apply to a given ATR 42, check whether each action has already been completed, and where not, perform the required one-time actions within the stated time limit or before issuance of a Certificate of Airworthiness.

The Directive targets a defined population through its mechanics rather than by a legislative-style definitional clause. The affected parties are:

• Registered operators and owners of ATR 42 series aeroplanes on the Australian register. The Directive explicitly applies to "ATR 42 series aeroplanes, as identified in the individual Airworthiness Directive (AD) listed Tables 1 and 2." That phrasing indicates that any ATR 42 whose serial/configuration falls within the scope of a listed DGAC or EASA AD must be assessed.

• Recently registered or imported ATR 42 aeroplanes. CASA’s Background states the Directive is issued because the DGAC and EASA ADs "may be applicable to recently registered or imported Australian aircraft." That identifies a practical trigger: aircraft brought into the Australian register after the original foreign-AD compliance date may still have outstanding actions.

• Maintenance organisations, aircraft engineers and Approved Maintenance Organisations engaged to perform inspections, modifications, or record searches. The Directive’s "determine applicability" and "perform actions required" steps will normally be executed by maintenance personnel or certifying engineers who must interpret foreign ADs and implement the technical work.

• Certifying authorities and personnel issuing a Certificate of Airworthiness. The compliance clause ties completion to the issue of a Certificate of Airworthiness, meaning aircraft awaiting initial or renewal CAO issuance will be subject to the requirement to complete applicable AD actions prior to receiving the CAO.

• Lessors, purchasers and brokers who are involved in ownership or transfer of ATR 42 aeroplanes. Because the compliance window is short and attaches to CAO issuance, parties transferring title, importing aircraft, or arranging registration should be aware of potential outstanding one-time AD requirements which may delay or condition CAO issuance.

• Parts suppliers and the aircraft manufacturer. If any listed AD mandates parts replacement or modification, suppliers and the manufacturer may be engaged to supply parts, service information or engineering data.

Who bears economic cost. The Directive places the direct compliance cost and administrative burden on the operator/owner of the aircraft to determine applicability and to perform any outstanding AD actions. Indirect costs may be borne by maintenance organisations who perform the work, by buyers/lessors if the aircraft cannot be delivered or certificated pending compliance, and by airports or operators if aircraft are prematurely grounded for work.

Who decides. The operator or responsible maintenance/engineering staff decide applicability based on aircraft serial number, configuration, maintenance records and the foreign AD texts, and then must decide to carry out the specified actions if not already accomplished. CASA has exercised regulatory authority by issuing the Directive; the Directive does not itself prescribe discretionary waivers or alternative means of compliance, therefore decisions about alternatives would need to be escalated to CASA or handled per normal approval routes, but the Directive does not describe those routes.

Duties imposed by the Directive are narrow in wording but broad in effect for affected aircraft.

Primary duties

• Determine applicability of the DGAC and EASA ADs listed in Table 1 and Table 2. The Directive’s Requirement 1 is explicit: "Determine the applicability of the ADs issued by the Direction Générale de l’Aviation Civile of France (DGAC), listed in Table 1, and the ADs issued by the European Aviation Safety Agency (EASA), listed in Table 2." That requires a fact-based assessment against each AD’s applicability criteria, which will typically include serial numbers, modification states, and specific component numbers.

• Perform the actions required by any applicable DGAC or EASA AD that has not been previously accomplished. The Directive’s Requirement 2 is also explicit: "If it is determined that an DGAC or EASA AD listed in Table 1 or 2 is applicable and has not been previously accomplished, perform the actions required by that AD." The substantive content of those actions is not reproduced; operators must consult the foreign ADs themselves for the technical steps.

• Meet the stated compliance timetable. The Directive requires completion of Requirements 1 and 2 "Within 30 days after the effective date of this Directive or prior to the issue of a Certificate of Airworthiness, whichever occurs first." That creates a strict timing obligation and an administrative trigger in the Certificate process.

Implied duties

• Maintain and produce records to demonstrate that the applicable ADs have been determined and either complied with or previously accomplished. Because the Directive conditions action on whether the AD "has not been previously accomplished," operators must be able to show documentary evidence of prior compliance where claimed.

• Consult external AD sources. The Directive points operators to EASA and DGAC AD databases via URLs, implying a duty to obtain and follow the foreign-AD texts.

Rights and limitations in the Directive

• No express exemptions or alternative means of compliance (AMOC) in the Directive text. The Directive does not contain clauses allowing deviation, time extension, or AMOC; it therefore sets a default expectation of strict compliance with the foreign ADs within the stated timeframe. If an operator wishes to seek an alternative approach, the Directive does not specify the administrative route for approval in this text.

• Narrow scope to listed ADs. The Directive does not create new technical requirements beyond the listed ADs; it merely imports and enforces, within Australia, the obligations created by those State-of-Design ADs for Australian-registered ATR 42 aircraft.

• Acknowledgement of non-applicability. The Background expressly acknowledges that due to manufacture date, configuration and modification status "not all the ADs listed in Table 1 and 2 will be applicable to all ATR 42 series aeroplanes." That limits the duty in practice to those ADs that actually apply.

Operational consequences of duties

• The operator must undertake an accurate applicability review, which will typically require checking the aircraft logbook and modification records against each foreign AD’s applicability criteria listed in the source AD.

• If remedial work is required, the operator must procure parts, schedule maintenance, and update maintenance records and the Certificate of Airworthiness filing, possibly delaying CAO issuance.

• The Directive creates a short compliance runway, so operators of recently imported or registered ATR 42s must prioritise this work to avoid administrative or operational delay.

All of these duties are stated in the Directive as the necessary steps to "ensure all State of Design ADs are complied with" for ATR 42 aircraft on the Australian register.

The Directive text sets out obligations and a compliance timetable, but it does not specify penalties, monetary fines or criminal sanctions within its text. The Directive requires operators to determine applicability and to perform required actions within 30 days after the effective date or before issuance of a Certificate of Airworthiness, whichever occurs first. The document is issued by CASA, and is signed by a CASA delegate, indicating that it is an enforceable airworthiness instrument under CASA’s regulatory framework, but the Directive itself contains no clause that states specific enforcement mechanisms, penalty amounts, or administrative sanctions.

What the Directive does show

• Mandatory compliance requirement. By stating specific Requirements and a compliance timeframe, the Directive creates a mandatory regulatory obligation for operators of applicable ATR 42 aircraft. In aviation regulatory practice, such ADs are compliance instruments; the Directive’s authority derives from CASA’s statutory powers to ensure continuing airworthiness. However, the Directive text does not enumerate the sanctions for non-compliance.

• Link to Certificate of Airworthiness. The compliance rule referencing the issuance of a Certificate of Airworthiness creates an immediate administrative lever. If applicable actions are not performed prior to CAO issuance, the issuing authority or certifying official would face a conflict with the Directive’s terms, and CAO issuance may be withheld until compliance is shown. The Directive itself does not state that CAO will be withheld, but the conditional wording implies it may affect CAO issuance.

Enforcement risks and practicalities

• Enforcement likely proceeds under CASA’s general statutory powers rather than under penalty clauses included in this Directive, because the Directive contains no penal provision. The Directive does not describe CASA’s rectification or sanction pathways, nor does it direct operators to apply for relief or exemptions.

• For operators, the absence of explicit penalty detail does not remove commercial and operational consequences. Failure to comply may lead to CASA intervention, potential grounding orders, refusal of CAO issuance, or other administrative action under CASA’s general regulatory regime. Those possible outcomes are not described in the Directive text, therefore operators must treat the Directive as mandatory and manage compliance.

• Proof and record-keeping. Because the Directive conditions the duty on whether an AD "has not been previously accomplished," operators will need to maintain or produce records demonstrating prior accomplishment to avoid repeating work. If records are insufficient, CASA may treat the action as outstanding.

In short, the Directive itself does not list penalties or enforcement procedures; it prescribes obligations and a compliance timetable and is signed by a CASA delegate. The regulatory effect and enforcement of compliance therefore depends on CASA’s broader regulatory powers and on administrative processes linked to Certificate of Airworthiness issuance, but the Directive does not specify details within its text.

The Directive is an instrument in the airworthiness regulatory ecosystem, and its interaction with other legal instruments is primarily operational.

Interaction with State-of-Design ADs (DGAC and EASA)

• Importing foreign AD obligations. The Directive explicitly requires operators to determine applicability and comply with specific DGAC and EASA ADs listed in Tables 1 and 2. The substantive technical mandates are contained in those foreign ADs, not in the CASA text. Therefore, the Directive operates by incorporating or importing certain foreign AD requirements into Australian continuing airworthiness obligations for ATR 42 aircraft.

• Reference to external sources. The Directive provides URLs for accessing the EASA and DGAC AD databases. That cross-reference means an operator must consult and follow foreign ADs as authoritative for the technical steps, while CASA’s Directive creates the Australian obligation to ensure those ADs have been complied with.

Interaction with Certificate of Airworthiness procedures

• Timing linked to CAO issuance. The Directive conditions compliance to be within 30 days after the Directive’s effective date or prior to the issue of a Certificate of Airworthiness, whichever occurs first. That creates a direct operational interaction with the CAO process. Certifying engineers and issuing authorities must ensure completion of applicable AD items before issuing the CAO, or the operator must show compliance within 30 days if CAO issuance occurs first.

Interaction with continuing airworthiness obligations

• Continuing airworthiness framework. The Directive addresses continuing airworthiness by requiring that outstanding one-time actions mandated by State-of-Design ADs be performed. It supplements, rather than replaces, operators’ existing continuing airworthiness obligations. The Directive makes no amendment to operating regulations or maintenance standards; it imposes an AD-specific obligation consistent with CASA’s continuing airworthiness role.

Jurisdictional and international law considerations

• Relationship between CASA and State-of-Design authorities. The Directive is a domestic instrument effectuating the State-of-Design ADs’ policy intent for Australian-registered aircraft. It does not alter the legal status of the DGAC or EASA ADs abroad, but it requires Australian compliance with those foreign ADs to the extent they are applicable to aircraft on the Australian register.

• No explicit interaction with statutory penalty provisions. The Directive does not cite specific provisions in the Civil Aviation Act or Civil Aviation Regulations that provide for penalties or enforcement. It therefore operates as an administrative directive whose enforcement will be handled through CASA’s broader legal powers, though the Directive text does not specify those interplays.

Practical interactions for affected parties

• Maintenance scheduling and CAO timing must be coordinated. Where CAO issuance is pending, compliance obligations under the Directive may affect scheduling of maintenance, procurement of parts, and the CAO workflow.

• Recordkeeping and proof of prior compliance will determine whether remedial actions are required. The Directive’s "previously accomplished" threshold interacts with record requirements under the continuing airworthiness regime to determine whether work must be repeated.

• Operators importing aircraft must reconcile foreign compliance histories with Australian expectations. The Directive explicitly reasons that some recently registered or imported aircraft may still owe one-time actions required by the State-of-Design ADs.

Overall, the Directive operates as an instrument that ties an Australian continuing airworthiness requirement to foreign ADs and to CAO processes, without creating new technical specifications itself beyond the requirement to comply with the listed foreign ADs.

The document itself contains the administrative provenance relevant to this instrument and does not show any subsequent amendments within its text. The explicit administrative data found in the Directive are:

• Identifier: AD/ATR 42/1 (also repeated as AD/ATR 42/1 AD/ATR 42/1 in the text).

• Issuance and signing: Signed by David Punshon, Delegate of the Civil Aviation Safety Authority, dated 8 June 2007.

• Effective date: "This Airworthiness Directive becomes effective on 22 June 2007."

• Label: 8/2007 DM printed on the document, consistent with the June 2007 date.

The text contains revision indicators for many of the listed DGAC and EASA ADs, as shown by suffixes such as R1 and R2 in Table 1 entries (for example F-1986-085-002 R1, F-1988-051-010 R2, etc.) and the EASA entries dated 2006 in Table 2. Those revision markers are part of the State-of-Design AD identifiers imported into the Directive; they imply that CASA selected the latest or relevant revision(s) of the foreign ADs at the time of issuing this Directive.

What is not in the Directive

• The Directive contains no internal amendment history showing prior versions of the CASA AD itself. There is no note of previous CASA directives or earlier iterations of AD/ATR 42/1 in the text.

• There is no schedule in the Directive for future amendments, no sunset clause, and no conversion to a regulatory provision in the Civil Aviation Regulations within the text.

Where to look for future or past changes

• Because the Directive references external foreign AD databases, any later EASA or DGAC AD revisions affecting the ATR 42 may be available from those databases. The Directive does not automatically update itself to incorporate future foreign ADs; it applies to the specific AD identifiers listed.

• Amendments to CASA ADs, revocation or superseding instruments would be recorded in CASA’s official AD publication channels or in the Australian Airworthiness Notices if they arise, but the Directive as provided contains only its original issuance and effective date metadata.

In practical terms, the Directive should be treated as the June 2007 CASA instrument that imported a defined set of foreign ADs at that point in time; operators should check for any subsequent CASA ADs or changes to ensure that later directives have not altered or superseded AD/ATR 42/1.

The Directive text contains no references to litigation, judicial review, or precedent, and does not list any legal challenges. There is no litigation history recorded in the instrument itself.

What the absence of litigation references means

• The document is an administrative airworthiness instrument issued by CASA and signed by a delegate. The Directive does not record any judicial proceedings, nor does it claim that it has been subject to court proceedings, nor does it cite court decisions or legal interpretations.

• The lack of litigation references does not imply that the Directive is immune from legal challenge under administrative law; it simply means that no litigation history is contained in the text. If parties wished to challenge the Directive’s validity, or seek review of enforcement action arising from it, any such litigation would be pursued under applicable administrative and judicial review processes outside the scope of this Directive text.

Practical considerations

• For operators concerned about legal risk, the Directive imposes an operational compliance requirement with a short timetable. Operators should prioritise compliance or seek clarification from CASA through official channels if they require legal or regulatory assurance. The Directive does not describe a mechanism for seeking interim relief or stay pending review.

• Because the Directive draws on foreign ADs, disputes about technical applicability, interpretation of foreign AD language, or the sufficiency of evidence of prior compliance could give rise to administrative contestation or, in theory, judicial review. The Directive itself does not provide guidance on appeal or review routes.

In sum, AD/ATR 42/1 contains no litigation history in the document provided. Any disputes about its application or enforcement would be handled via CASA’s administrative framework and, if contested, would emerge in the judicial record outside the Directive’s text.

Operators and maintenance providers should be aware of several practical pitfalls and sources of implementation risk arising directly from the Directive’s structure and wording.

1. Applicability confusion because the Directive lists AD identifiers but not technical instructions. The CASA Directive lists many DGAC and EASA ADs by identifier, issue date and title, but it does not include the substantive remedial text. Operators must obtain each foreign AD from the provided EASA and DGAC URLs and then interpret the applicability criteria contained therein. Mistakes in reading applicability criteria may either lead to unnecessary work or to failure to perform required action.

2. "Previously accomplished" burden. The Directive conditions work on whether the foreign AD action "has not been previously accomplished." Proof of prior compliance rests on the operator to produce records. Incomplete or ambiguous logbooks may cause CASA or certifiers to treat the action as outstanding, resulting in repeat work or delays in Certificate issuance.

3. Short compliance window. The Directive requires actions "Within 30 days after the effective date of this Directive or prior to the issue of a Certificate of Airworthiness, whichever occurs first." For aircraft that are newly imported or in the Certificate issuance pipeline, this compresses time for applicability reviews, parts procurement and execution, potentially delaying CAO issuance or requiring rushed maintenance that complicates scheduling.

4. One-time actions with passed compliance dates. The Background states that the listed State-of-Design ADs "require one time actions for which the compliance date and/or period has passed." That often means there is no scheduled recurring check; however, if an aircraft has not had the one-time action completed, it may now need immediate modification or inspection to retro-fit. This can be expensive and parts or approved repair schemes may be scarce.

5. Revision markers R1/R2 and version control hazards. Many DGAC AD entries include revision markers (R1, R2). Operators must ensure they consult the correct revision of each AD. Citing the wrong revision could lead to wrong technical work or non-conformance.

6. Differences between State-of-Design ADs and Australian practice. The Directive imports the foreign ADs for Australian-registered aircraft, but it does not explain how to handle differences in technical standards, approved parts lists, or equivalent engineering solutions. Where a foreign AD mandates a modification that relies on parts or approvals not readily available in Australia, operators may need to engage with CASA for acceptance of alternative means, but the Directive does not set out that route.

7. Certificate of Airworthiness linkage. The "or prior to the issue of a Certificate of Airworthiness, whichever occurs first" clause can create a race between CAO issuance and compliance. If a CAO is issued without the required actions being demonstrably completed, certifying engineers and the issuing authority may face regulatory friction. Operational stakeholders must coordinate to avoid unintended CAO refusals or administrative disputes.

8. Record-keeping precision required. Given the Directive’s reliance on a "previously accomplished" check, operators must ensure traceable maintenance records, component serial number documentation, and service compliance certificates are in order. Poor documentation increases the risk of rework and potential grounding.

9. Multiple stakeholders and contractual friction. For leased aircraft, transfer or sale agreements must account for potential outstanding AD actions. If an aircraft is imported with incomplete maintenance history, the new Australian operator may inherit the compliance obligation, despite contractual expectations.

10. No explicit AMOC or extension mechanism in the text. The Directive does not provide a stated pathway for an alternative means of compliance or timeline extension. Operators requiring flexibility may need to approach CASA by standard channels, but the Directive does not supply procedural guidance.

Operators should treat the Directive as an immediate compliance-altering instrument, conduct a priority applicability and records review, and manage procurement and maintenance scheduling to meet the short deadlines.

The following is a practical compliance checklist distilled from the Directive’s Requirements, Compliance paragraph and Background, aimed at helping operators, engineers and certifiers execute the obligations promptly and defensibly.

1. Identify the affected airframes. Start with each ATR 42 on your Australian register, or pending registration. Record the manufacturer serial number, variant, production and modification history.

2. Obtain the listed foreign AD texts. Use the URLs included in the Directive: http://ad.easa.europa.eu/ and http://www.gsac.fr/php/P_ConsignesNav.php, and access each DGAC AD listed in Table 1 and each EASA AD listed in Table 2. Ensure you pull the revision corresponding to the AD identifier shown in the Directive (e.g., entries with R1, R2).

3. Determine applicability AD-by-AD. For each AD, compare its applicability criteria (serial numbers, effective serial ranges, parts numbers, modification states) with the aircraft’s build/configuration and with its maintenance records. Document the findings, with an explicit notation for each AD: applies / does not apply / requires further technical review.

4. Review maintenance records for prior accomplishment. Where an AD is assessed as applicable, check the maintenance logbook, release certificates and previous AD compliance records to determine whether the AD’s required action has "been previously accomplished" as per the Directive. Keep copies of the relevant work orders, logbook entries, and compliance certificates.

5. If action outstanding, procure technical instructions and parts. For each applicable AD not previously accomplished, retrieve the corrective steps from the foreign AD, identify required parts, service bulletins or engineering orders, and obtain parts or authorisations needed for compliance.

6. Schedule the work immediately. The Directive requires completion "Within 30 days after the effective date of this Directive or prior to the issue of a Certificate of Airworthiness, whichever occurs first." Schedule maintenance slots so the actions can be completed before the earlier of those triggers. If a pending CAO issue is within the 30-day window, prioritise actions that affect CAO issuance.

7. Use approved maintenance providers and approvals. Ensure that the work is performed by appropriately certificated engineers or approved maintenance organisations. Where the foreign AD requires specific OEM-approved modifications or parts, comply with those instructions or obtain CASA acceptance for any alternative.

8. Record compliance thoroughly. After completing each AD action, make maintenance logbook entries identifying the AD identifier and revision, the work performed, parts used (including part and serial numbers where applicable), the certifying engineer and a statement of compliance. Keep traceable documentation to demonstrate that the action was "previously accomplished" going forward.

9. Liaise with the certifying authority for CAO issuance. If CAO issuance is pending, provide the CAO issuing authority or certifying engineer with the compliance records. If there is a timing conflict, notify CASA early and document communications and interim measures. The Directive itself does not set an AMOC or extension route, so early engagement is advisable.

10. Maintain an audit trail of applicability determinations. Because the Directive conditions action on the result of the applicability check, retain the rationale and evidence for each determination. That reduces the risk of rework and provides proof in case of audit or regulatory question.

11. Consider supply chain and engineering constraints. For some one-time actions where parts are scarce or modifications require design approval, contact the manufacturer, parts suppliers or CASA early to identify acceptable alternatives or to obtain necessary engineering approvals.

12. Where uncertain, seek CASA guidance. If the applicability determination is unclear or the foreign AD’s technical requirements conflict with Australian design approvals, apply to CASA for clarification. The Directive does not specify the administrative route for relief, but CASA is the issuing authority and can be engaged for guidance.

Cost and operational expectations

• Budget for one-time costs. The Background notes these are one-time actions; they are likely to involve discrete costs for parts and labour, potentially concentrated and immediate rather than ongoing.

• Expect potential CAO delays. If compliance cannot be demonstrated before CAO issuance, CAO issuance may be delayed until compliance or satisfactory evidence of prior accomplishment is presented.

• Plan for record remediation. If documentation is incomplete, plan time and resources to reconstruct compliance histories or to repeat inspections.

By following the steps above and keeping clear records of applicability determinations and remedial work, operators can implement the Directive’s Requirements 1 and 2 within the short timeframe, and ensure the aircraft’s continuing airworthiness obligations under CASA’s instruction are demonstrably met.