AD/EMB-120/25 Amdt 3 - Nacelle Structure

The AD is built around a small set of interlocking concepts: applicability, mandated technical action, compliance timing, reference to a manufacturer service bulletin, cross-reference to a foreign authority AD (CTA), amendment history, and the safety rationale.

Applicability: The AD limits its scope to specific serial-numbered EMB-120 aeroplanes: 120003, 120004 and 120006 through 120336. Practically, this is a closed list; aircraft outside these serial numbers are not within the instrument’s stated scope. The AD text therefore ties the mandatory action to a defined set of airframes rather than to the EMB-120 model generically.

Mandated technical action: The Requirement clause is precise about the technical remedy. It instructs that operators must “modify the upper rear nacelle structure in accordance with Embraer Service Bulletin 120-54-0035 Revision 2 or later revision approved by the CTA.” The technical fix named in the Background is the installation of a fire resistant plate to the upper rear nacelle structure. The link between the manufacturer’s service bulletin and the regulatory mandate is direct: the AD makes the SB the required method of compliance, subject to a CTA-approved later revision.

Compliance metric and timing: Compliance is measured in “hours time in service,” with the specified action required “within 2,000 hours time in service after 21 May 1998.” The AD states that the compliance time is unchanged by the 2005 amendment, preserving the original compliance metric despite subsequent amendments. The AD also records an effective date for the amendment (14 April 2005), which governs when this amendment’s permissive changes (for example, allowing later CTA-approved revisions of the service bulletin) take effect.

Cross-reference to CTA AD: The AD refers to “CTA AD 97-11-03R2 Amdt 39-1068” and notes that Amendment 2 was issued in response to a revision of the related CTA AD. The AD therefore tracks changes made in the CTA AD: Amendment 2 removed the requirement to replace the exhaust duct rear bracket because that removal was made in the related CTA AD. Amendment 3 (this instrument) allows the use of later CTA-approved revisions of the Embraer service bulletin. The AD thus operates in an inter-authority regulatory ecosystem where a CTA AD informs CASA’s directive.

Amendment history and administrative signature: The AD records a sequence,original AD effective 21 May 1998; Amendment 1 which expanded applicability and required additional “PART II” action; Amendment 2 responding to the CTA AD revision that removed the exhaust duct rear bracket replacement requirement; and this Amendment 3, which permits later CTA-approved service bulletin revisions and is effective 14 April 2005. The AD carries the signature block of “David Villiers, Delegate of the Civil Aviation Safety Authority,” dated 4 March 2005, indicating the CASA delegate as the decision maker registering the amendment.

Safety rationale: The Background outlines the operational hazard that the AD intends to address: an engine-exhaust fire following an engine failure penetrated the nacelle hydraulic compartment, causing the loss of both hydraulic systems and extensive nacelle damage. The AD’s prescribed action,installation of a fire resistant plate,is stated as the corrective measure to reduce the risk of recurrence.

The document is primarily a prescriptive maintenance/airworthiness instrument that converts a manufacturer’s service recommendation into a mandatory modification for specifically identified airframes, links compliance to elapsed service hours from an historical start date, and aligns its technical prescription with the CTA’s approvals and revisions.

The AD directly affects operators and owners of the Embraer EMB-120 aircraft listed by serial number: 120003, 120004 and 120006 through 120336. That listing creates a bounded set of aircraft to which the mandatory modification applies; any party operating or owning these serial-numbered airframes is within the AD’s stated scope.

Relevant affected parties, as implied by the text, include:

• Aircraft operators who are responsible for maintaining airworthiness of the specified serial-numbered EMB-120 aircraft. They must plan, schedule and pay for the modification described.
• Aircraft owners, if distinct from operators, since owners typically bear capital and structural responsibilities for modifications and record-keeping.
• Maintenance organisations and engineers engaged to perform the modification in accordance with Embraer Service Bulletin 120-54-0035 Revision 2 or a later CTA-approved revision. These providers must follow the service bulletin method and ensure their work records show compliance with the version of the SB approved by the CTA.
• Regulators and delegates within the Civil Aviation Safety Authority; the instrument is issued by a CASA delegate (document signed by “David Villiers, Delegate of the Civil Aviation Safety Authority, 4 March 2005”), implying CASA’s administrative role in issuing and recording the AD.
• Potentially, other parties with responsibility for airworthiness records and continuing airworthiness management, such as continuing airworthiness managers, accountable managers, maintenance control authorities and quality assurance personnel inside operators and maintenance organisations.

The AD also has an indirect effect on other stakeholders:

• Flight operations planning: operators must schedule out-of-service time to accommodate the modification, which affects rostering, utilisation and revenue generation, although the AD itself does not quantify those costs.
• Parts suppliers or stock-holders for the required materials in Embraer Service Bulletin 120-54-0035: the AD’s mandate to install a fire resistant plate will create discrete procurement needs for parts called for by the SB.
• Record-keeping and compliance auditors: persons or bodies who verify compliance with airworthiness directives will need to inspect maintenance records to confirm the required modification and the specific SB revision used.

The AD is silent on compensation or cost-sharing arrangements. The text places the legal obligation to implement the modification on the operators/owners of the listed aircraft because it converts the service bulletin into a mandatory requirement for those serial numbers. The AD also requires that the SB used be either Revision 2 or a later revision approved by the CTA, creating an administrative task for affected operators to confirm which SB revision they are using and to document CTA approval where applicable.

Finally, the AD’s amendment history demonstrates that the affected population may need to consult earlier amendments: Amendment 1 expanded applicability and required additional “PART II” action, which suggests that parties must check prior amendment texts for any additional obligations that remain relevant to their aircraft. Amendment 2 removed the requirement to replace the exhaust duct rear bracket, which means that some earlier-acted tasks may have been superseded; affected parties must track which obligations persist and which have been rescinded.

Key duties imposed by the AD are explicit and narrowly described in the document’s Requirement and Compliance clauses.

Duties:

• Modify the upper rear nacelle structure: The principal duty is to carry out the structural modification. Specifically the AD states: “Modify the upper rear nacelle structure in accordance with Embraer Service Bulletin 120-54-0035 Revision 2 or later revision approved by the CTA.” That duty requires operators or authorised maintenance organisations to perform the modification following the procedures and parts lists set out in the cited service bulletin revision.
• Use CTA-approved revisions: Where operators rely on a later service bulletin revision, the AD requires that the later revision be “approved by the CTA.” This creates a duty to confirm and document CTA approval of any service bulletin revision used to comply.
• Meet the compliance time: The AD sets the compliance time as “Within 2,000 hours time in service after 21 May 1998,” and the AD expressly notes that “The compliance time is unchanged by this issue.” Maintaining accurate hours-time-in-service records is therefore a duty, because compliance is measured against that metric.
• Observe amendment provisions: The AD records that Amendment 1 expanded applicability and added “PART II” action, Amendment 2 aligned the AD with an updated CTA AD by removing an earlier requirement (replace exhaust duct rear bracket), and Amendment 3 permits the use of later CTA-approved revisions of the service bulletin. A duty follows to consult the amendment history and ensure compliance with any part of the AD that remains operative.

Rights and procedural points (as visible in the text):

• Use of later CTA-approved SB revisions: The AD grants the functional right to use a later Embraer service bulletin revision provided that revision has CTA approval. That is an authorised pathway for compliance and means operators are not constrained to Revision 2 if a CTA-approved later revision exists.
• Explicit scope limitation: By listing the serial numbers, the AD limits mandatory obligations to a defined set of aircraft. Operators of EMB-120 airframes with serial numbers outside the listed range do not have an obligation under this AD, according to the document’s Applicability clause.
• Implicit recordation and reference rights: The AD cross-references CTA AD 97-11-03R2 Amdt 39-1068. Affected parties have the right and duty to consult that CTA AD for context because Amendments 1 and 2 altered obligations in response to the CTA AD. The AD explicitly references that other document, indicating it as part of the compliance context.

What the AD does not state:

• The AD does not state any rights to compensation, cost recovery, or timelines beyond the 2,000-flight-hours metric. It does not specify dispute-resolution mechanisms, appeal rights, or a process for seeking exemptions or alternative methods of compliance within the text provided.
• The AD does not set out the technical scope of PART II mentioned in Amendment 1; it merely records that additional PART II action was required in Amendment 1. Where affected parties need clarity on PART II they must consult Amendment 1 text itself.

Practical compliance duties that follow from the AD text include acquiring and using the correct Embraer service bulletin revision, documenting CTA approval for later revisions used, keeping and referencing hours time-in-service records to demonstrate compliance within the prescribed 2,000 hours after 21 May 1998, and ensuring maintenance records evidence the modification in accordance with the SB and the AD effective dates and amendments.

The supplied AD text does not contain express clauses that set monetary penalties, criminal sanctions, civil remedies, administrative fines, or explicit procedures for enforcement and sanctions. The document focuses on the technical requirement, applicability, compliance time, and amendment history; it does not include an enforcement or penalty section within the text provided.

What the AD does make enforceable in substance is a mandatory technical requirement tied to specific aircraft: the modification of the upper rear nacelle structure in accordance with Embraer Service Bulletin 120-54-0035 Revision 2 or a later CTA-approved revision must be performed within the prescribed compliance time metric. The AD records the compliance criterion (“Within 2,000 hours time in service after 21 May 1998”) and records amendment effective dates; those elements frame the window during which the technical action had to be performed.

Because the instrument itself does not specify enforcement mechanisms, affected persons should note the following points derivable from the text and from the administrative presentation of the AD:

• The AD is issued and signed by “David Villiers, Delegate of the Civil Aviation Safety Authority,” dated 4 March 2005. The signature indicates administrative issuance by CASA; any routine enforcement liabilities or administrative follow-up would ordinarily sit with the issuing authority. The AD text, however, does not state CASA’s enforcement powers or procedures.
• The AD explicitly references CTA AD 97-11-03R2 Amdt 39-1068 and permits CTA-approved later SB revisions. That cross-reference indicates that compliance will be measured against both the service bulletin method and the CTA-approved revisions. Any enforcement or verification of compliance will therefore focus on whether the modification was performed per the approved SB and within the compliance time parameter.

Consequences of silence in the text:

• The AD’s lack of specified penalties means the text itself does not provide a statutory enforcement regimen; it sets the technical obligation, leaving enforcement mechanisms implicit or located outside the instrument’s text. Users of this AD must be aware that any formal enforcement procedure, penalties, or remedies will be governed by the broader regulatory framework in which CASA operates, but those external enforcement provisions are not set out in the AD text supplied and cannot be asserted from this document alone.

Operational enforcement implications (factual, based on the AD’s content):

• The AD requires operators to make a structural modification and to document compliance with a named service bulletin revision. In practical terms, proof of compliance will rest on maintenance records, SB revisions used, and hours-in-service records demonstrating that the modification occurred within the compliance metric. The AD therefore creates administrative record-keeping obligations that will be the primary evidence used in any verification or audit, although the AD itself does not describe audits or inspections.
• The AD’s amendment history (original AD effective 21 May 1998; subsequent amendments including Amendment 3 becoming effective 14 April 2005) means that a regulator checking compliance must reconcile which obligations persisted and which were removed (for example, Amendment 2 removed the requirement to replace the exhaust duct rear bracket). The AD itself does not set out how a regulator will handle historic compliance actions taken under superseded text.

In short, the document stipulates a mandatory modification and a compliance window but does not set out within its own text the penalties, adjudication procedures, or enforcement processes that will apply where compliance is not met. Those enforcement modalities, if any, are not contained within the AD supplied and must be sought in the broader regulatory instruments or agency procedures that govern CASA’s enforcement activities.

The AD explicitly cross-references and responds to a related CTA airworthiness directive: “CTA AD 97-11-03R2 Amdt 39-1068 refers.” The AD’s amendment history reflects that it was updated to align with revisions in that CTA AD: Amendment 2 was issued “in response to a revision of the related CTA AD, which removed from the text of the previous CTA AD, the requirement to replace the exhaust duct rear bracket.” Amendment 3 (this instrument) allows use of later CTA-approved revisions of Embraer Service Bulletin 120-54-0035. These explicit references show that the AD operates in a networked fashion with at least one foreign authority document as a datum point for technical content and obligations.

Relation to manufacturer service documentation:

• The AD converts the Embraer Service Bulletin 120-54-0035 into a mandatory regulatory requirement for the listed serial-numbered aircraft. It does this by specifying that the modification be performed “in accordance with Embraer Service Bulletin 120-54-0035 Revision 2 or later revision approved by the CTA.” That creates a direct operational relationship between the regulator’s directive and the manufacturer’s technical instructions; the AD obliges operators to use the SB as the method of compliance.

Amendments and supersession:

• The AD’s amendment history shows that it has been modified in response to either additional technical findings (Amendment 1 expanded applicability and required additional “PART II” action) or to align with the CTA’s revisions (Amendment 2 removing the exhaust duct rear bracket replacement requirement). The current amendment (Amdt 3) authorises later CTA-approved revisions of the SB. Thus, the AD interacts dynamically with both manufacturer documentation and foreign authority ADs: later revisions of the SB are usable if approved by the CTA, and the AD has been amended in response to CTA AD amendments.

Interplay with compliance timing:

• The compliance time is measured in hours time in service and referenced to a specific date: “Within 2,000 hours time in service after 21 May 1998. The compliance time is unchanged by this issue.” That timing interrelates the AD’s obligation with operational metrics that operators maintain under airworthiness and maintenance programmes. Tracking hours time in service is therefore the concrete mechanism by which this AD interlocks with operational record-keeping and maintenance law or regulation, although those external record-keeping rules are not stated in the AD itself.

Scope limitation and legal effect:

• The AD limits obligations to specified serial numbers. That interacts with ownership and operational responsibilities, where only those aircraft listed are within the AD’s stated scope. The AD therefore interacts with governance rules that determine who is responsible for modifications for a given aircraft , notably operators and owners , but the AD text itself does not recite those governance rules.

Silence as interaction:

• The AD does not set out enforcement procedures, remedies, exemptions, or administrative appeal routes. Those governance elements would be found in the broader Australian aviation regulatory framework administered by CASA and other legal instruments, but this AD does not include them. Consequently, the AD’s text is technically prescriptive but legally partial: it specifies what must be done and for which aircraft, how compliance must be achieved (per SB and CTA approvals), and when compliance had to occur; it does not, in the text provided, specify how non-compliance will be addressed within other laws.

Practical consequence for compliance with multiple instruments:

• Operators must treat Embraer Service Bulletin 120-54-0035 and CTA AD 97-11-03R2 Amdt 39-1068 as essential complementary documents when implementing the AD. The AD’s amendment history shows that obligations can be added or removed in response to CTA AD changes; therefore, a compliance programme must reconcile the current AD text with the applicable SB revision and the referenced CTA AD. The AD itself therefore establishes a nexus requiring coordination between the operator, the manufacturer’s instructions, and the CTA’s approvals and versions.

In summary, the document interacts primarily with the manufacturer’s service bulletin and the referenced CTA AD. It does not itself provide enforcement mechanics or invoke other named Australian statutory provisions within the text supplied; those elements, if relevant, lie outside the AD’s text and would need to be identified in the broader regulatory corpus.

The AD text supplied records a clear amendment path and supply-chain of modifications to the directive. The document itself is identified as “AD/EMB-120/25 Amdt 3” and includes a short history in its Background and annotation sections. The recorded sequence in the supplied text is:

• Original AD: The original issue of this Airworthiness Directive “became effective on 21 May 1998.” That establishes the first mandatory baseline and the start date used for the compliance time metric (“within 2,000 hours time in service after 21 May 1998”).

• Amendment 1: The text records that “Amendment 1 expanded the applicability and required additional ‘PART II’ action.” The AD text provided does not include the specific content of PART II or the detailed nature of the applicability expansion, but it explicitly records that these were the substantive changes made in Amendment 1. Parties must therefore consult the text of Amendment 1 to determine exactly what was added in PART II and which additional aircraft or serial numbers were included, if any.

• Amendment 2: The text states that “Amendment 2 was issued in response to a revision of the related CTA AD, which removed from the text of the previous CTA AD, the requirement to replace the exhaust duct rear bracket. Although there was no additional technical requirement, this Directive was amended to reference the latest CTA AD.” This records two concrete consequences: (1) a CTA AD revision removed a prior requirement (replace exhaust duct rear bracket), and (2) CASA’s AD was amended to bring its text into alignment with the CTA change. The AD states that there was no additional technical requirement from Amendment 2, which suggests Amendment 2 was an administrative alignment rather than a new technical mandate.

• Amendment 3 (this document): The present text is “AD/EMB-120/25 Amdt 3” and is dated with an effective date: “This Amendment becomes effective on 14 April 2005.” The stated purpose of this amendment is to “allow the use of later CTA approved revisions of the referenced Embraer service bulletin.” That is a permissive amendment, broadening the set of acceptable service bulletin revisions that can be used to comply, conditional on CTA approval. The AD records that the compliance time is unchanged by this amendment: “Within 2,000 hours time in service after 21 May 1998. The compliance time is unchanged by this issue.” The amendment is signed by “David Villiers, Delegate of the Civil Aviation Safety Authority, 4 March 2005.”

Other annotations in the supplied text:

• The AD includes a “Note: CTA AD 97-11-03R2 Amdt 39-1068 refers.” This indicates the CTA AD version that was current for earlier amendments and which the AD references as the basis for prior changes.
• The Background paragraph also summarises the safety event prompting the directive and explains the technical fix (installation of a fire resistant plate to the upper rear nacelle structure).

What is not in the provided text:

• The AD text supplied does not provide the full text of Amendment 1’s PART II action, so readers must obtain that text to know what PART II required and whether any elements of PART II remain applicable.
• The AD does not include the full prior amendment texts or the CTA AD content; it references those documents and records high-level changes (for example removal of the exhaust duct rear bracket replacement requirement) but does not provide the full prior language.

Practical effect of the amendment history:

• Operators and maintainers must reconcile work already carried out under previous amendments with the current AD text. For example, if an operator previously performed the exhaust duct rear bracket replacement that Amendment 2 removed, the AD records that removal; operators need to know whether previously performed actions remain required for life-of-type reasons even if removed from the AD. Because Amendment 3 allows later CTA-approved Service Bulletin revisions, parties have an authorised pathway to use later SB versions provided CTA approval is available and recorded.

The amendment history therefore documents the AD’s evolution from the original 1998 directive through at least two later amendment steps, culminating in the 2005 amendment that loosens the method-of-compliance restriction to permit later CTA-approved SB revisions. The supplied text shows a pattern of alignment with a CTA AD and administrative refinement of technical requirements over time.

The supplied AD contains no litigation history and does not reference any court decisions, legal challenges, or administrative appeals. The document’s content is purely administrative and technical: it records applicability, requirement, compliance timing, amendment history and the safety rationale. There are no internal citations to litigation, case names, tribunal determinations, or judicial review outcomes in the text provided.

What the AD does provide that is relevant to potential legal review:

• The AD is signed by a delegate of the Civil Aviation Safety Authority: “David Villiers, Delegate of the Civil Aviation Safety Authority, 4 March 2005.” That signature identifies the administrative decision-maker responsible for issuing the amendment. If a party were to challenge the AD, that signature block would indicate the administrative actor whose decision could be subject to review, but the AD text itself includes no record of any litigation, appeals or outcomes.
• The AD cross-references CTA AD 97-11-03R2 Amdt 39-1068 and records that its own Amendments 1 and 2 were made in response to changes in that CTA AD. Any legal challenges or interpretations surrounding those CTA documents would not appear in this AD text, and no such litigation is recorded here.

Absence of recorded litigation:

• Because no litigation is recorded in the AD text, readers must treat the document as silent on any disputes, judicial determinations, or administrative appeals. If one requires information about any legal challenges to the AD or its amendments, that information is not contained in the provided text and must be sought from external legal or administrative records.

Practical note for those assessing legal risk:

• The AD as provided does not narrate any past or ongoing litigation. For practitioners needing to know whether the AD has been litigated, or whether there are recorded judicial interpretations of its scope or applicability, a search outside this document would be necessary; such a search is not possible on the basis of the supplied text alone.

In sum, the AD’s supplied text records no litigation history; it is purely an administrative directive with technical content and an amendment trail, without judicial or tribunal material included.

The AD’s compact content includes several discrete points that could cause compliance or administrative pitfalls if overlooked. These are not speculative; they follow directly from the AD’s wording and amendment notes.

1. Compliance window predates current amendment:

   • The compliance metric is “Within 2,000 hours time in service after 21 May 1998” and the AD notes “The compliance time is unchanged by this issue.” The present amendment becomes effective 14 April 2005, which is many years after the 21 May 1998 baseline. Operators must note that the compliance metric originates from the original AD effective in 1998; the amendment does not extend the compliance deadline. Failure to note the historical baseline may create the mistaken impression that this amendment creates a new compliance clock; the AD expressly denies that.

2. Serial-number list contains a non-contiguous element:

   • The Applicability clause lists serial numbers 120003, 120004 and 120006 through 120336. Serial number 120005 is not included. A failure to verify precise serial number inclusion could lead to applying the AD to an aircraft not in scope or, conversely, missing a covered airframe because its serial number was overlooked. The AD’s scope is serial-number specific, so accurate identification is essential.

3. Service bulletin revision must be CTA-approved:

   • The AD allows compliance “in accordance with Embraer Service Bulletin 120-54-0035 Revision 2 or later revision approved by the CTA.” The conditional phrase “approved by the CTA” is a gating condition. Operators must obtain and document the CTA’s approval for any later SB revision relied upon. Using a later Embraer revision without CTA approval would not satisfy the AD as written.

4. Amendment-level differences and PART II:

   • Amendment 1 “required additional ‘PART II’ action.” The current AD text does not include PART II or its content; operators must consult Amendment 1 to determine what PART II required and whether those actions are still required or have been superseded. Overlooking the content of prior amendments risks non-compliance with residual obligations.

5. Removal of exhaust duct rear bracket replacement:

   • Amendment 2 removed the requirement to replace the exhaust duct rear bracket because the related CTA AD removed that requirement. If an operator previously replaced that bracket pursuant to an earlier AD text, they should check records to ensure that replacement remains serviceable and documented; conversely, operators who did not replace the bracket because of the Amendment 2 removal must ensure no other instrument requires it. The AD’s amendment notes create potential divergence between historical actions and current obligations.

6. Reliance on external CTA documents:

   • The AD references CTA AD 97-11-03R2 Amdt 39-1068. The scope and content of that CTA AD have driven prior amendments. Compliance therefore requires consulting the CTA AD for interpretive context; failure to do so could lead to misreading the AD’s intended obligations or missing cross-referenced changes.

7. No penalties or enforcement path in text:

   • The AD does not specify sanctions or enforcement procedures. This silence means affected parties cannot rely on the AD alone to determine the legal consequences of non-compliance. Parties must be cautious: absence of penalties in the AD text does not mean there are none under broader regulatory frameworks. That gap can be a procedural gotcha when assessing compliance risk.

8. Documentation and proof-of-compliance requirements are not enumerated:

   • The AD mandates a modification and references a service bulletin but does not set out the form or content of records proving compliance. Practitioners must ensure maintenance records clearly identify the SB revision used, the CTA approval for that revision if applicable, the hours-in-service at time of modification, and the serial number of the aircraft to create an auditable trail.

9. Effective date for amendment vs original requirement:

   • While Amendment 3’s effective date is 14 April 2005, the AD’s operative compliance clock was set in 1998. Newer personnel or contractors brought on after 2005 might incorrectly assume that Amendment 3 created a fresh compliance obligation beginning in 2005; the AD’s language explicitly prevents that assumption.

10. Technical scope may be broader than meets the eye:

• The Background states that the required action is the “installation of a fire resistant plate to the upper rear nacelle structure.” While the AD references the Embraer SB as the method, practitioners must ensure that all tasks and ancillary work in the SB (fasteners, structural reinforcements, inspections) are accounted for in the planning, not just the plate installation. The AD does not list technical subtasks; the SB will.

Each of these points is grounded in the AD text or its amendment annotations. Operators and maintainers should treat them as checklist items to avoid procedural missteps when implementing or verifying compliance with this AD.

The AD prescribes a single, specific path to compliance: modify the upper rear nacelle structure in accordance with Embraer Service Bulletin 120-54-0035 Revision 2 or a later revision that is approved by the CTA, and ensure the work is done within the compliance metric (“Within 2,000 hours time in service after 21 May 1998”). The following is a practical, source-grounded compliance checklist derived from the AD text and amendment notes.

1. Identify affected aircraft by serial number:

   • Confirm the aircraft’s serial number is one of: 120003, 120004 or in the range 120006 through 120336. The AD’s Applicability clause is the definitive scope statement in the document.

2. Confirm compliance timing:

   • The AD requires compliance “Within 2,000 hours time in service after 21 May 1998” and explicitly states “The compliance time is unchanged by this issue.” Calculate the hours-in-service baseline for the aircraft and the number of hours at the time of modification to verify the modification met that metric. Because the AD’s baseline predates the amendment, verify historical hours-in-service records as needed.

3. Obtain the correct service bulletin and CTA approval:

   • Acquire Embraer Service Bulletin 120-54-0035 Revision 2. If you intend to use a later Embraer revision, obtain evidence that the later revision is “approved by the CTA,” since the AD allows only CTA-approved later revisions. The AD’s Requirement clause makes CTA approval a condition for using later SB revisions.

4. Review amendment history and prior AD texts:

   • Consult Amendment 1 and Amendment 2 texts (both referenced in the AD’s internal history) to determine whether any additional “PART II” actions or historical requirements might remain relevant to your aircraft or maintenance records. Amendment 1 expanded applicability and added PART II; Amendment 2 removed the exhaust duct rear bracket replacement requirement. Reconcile your aircraft’s maintenance status with these changes.

5. Plan and execute the modification per the service bulletin:

   • Engage a suitably authorised maintenance organisation to perform the modification following the SB’s procedures, parts lists and quality standards. Ensure the SB revision used is Revision 2 or a later CTA-approved revision as required.

6. Document the work comprehensively:

   • Create maintenance records that identify the aircraft serial number, SB revision used, evidence of CTA approval for the SB revision if not Revision 2, the hours-in-service at the time of modification, the date of modification, the organisation and persons who performed the work, and any test or inspection outcomes specified by the SB. Given the AD’s silence on record format, provide unambiguous documentary proof that demonstrates compliance with the AD’s explicit clauses.

7. Retain proof of CTA approvals and cross-referenced ADs:

   • Because the AD references CTA AD 97-11-03R2 Amdt 39-1068 and permits CTA-approved SB revisions, retain copies of the relevant CTA AD and any CTA approval documentation for later inspection or audit.

8. Reconcile any previously performed actions:

   • If earlier modifications were performed pursuant to prior AD texts (for example, replacement of the exhaust duct rear bracket under a prior requirement later removed by Amendment 2), verify whether that action remains recorded and whether it affects current certification or continuing airworthiness records. Document the relationship between prior actions and the current AD status.

9. Verify regulatory filing or notification requirements:

   • The AD text does not specify any mandatory filing, notification, or form submission. Nonetheless, operators should follow their normal internal procedures for recording AD compliance and any CASA filing practices that apply in their organisation, ensuring internal audit trails exist.

10. Maintain ongoing oversight:

• Even after performing the modification, keep records of the SB revision used and CTA approval evidence because future audits, inspections or amendments may require proof of how compliance was achieved. Because the AD has an amendment history tied to CTA AD changes, maintain a practice of checking for subsequent AD amendments or related CTA AD updates that could alter the required maintenance regime.

In short, compliance requires: (a) confirming the aircraft is within the AD’s serial-number scope, (b) obtaining and following Embraer Service Bulletin 120-54-0035 Revision 2 or a CTA-approved later revision, (c) performing and documenting the modification within the compliance window established in 1998, and (d) reconciling any previous amendment-driven actions (such as PART II or bracket replacement) with current obligations. The AD’s text supplies the prescriptive steps (SB-based modification, CTA approval condition, serial-number scope and hours-in-service compliance clock); it does not list enforcement or submission procedures, so thorough record-keeping and reference to CTA AD 97-11-03R2 Amdt 39-1068 are necessary to create a defensible compliance trail.