AD/PC-12/51 - Main Landing Gear Special Bolts

The AD is structured around a small set of tightly defined engineering and regulatory concepts. These are the operative elements you must track if you are responsible for fleet airworthiness for affected PC-12s.

• Applicability by aircraft model and serial number. The AD applies to "All Model PC-12, PC-12/45 and PC-12/47 aircraft, with Manufacturer Serial Number 101 through MSN 749" that are "equipped with MLG assemblies and special bolts as listed below" (the AD then lists MLG assembly part numbers, special bolt part numbers and modification kit numbers). Applicability is therefore a conjunction: aircraft type + MSN range + presence of specific MLG/bolt/kits delivered before 31 December 2006, or held as spares.

• Identifying the hazard by manufacturing defect type. The AD states the manufacturer determined that "certain main landing gear bolts may be affected by hydrogen embrittlement." The manifest risk is decreased fatigue life of an MLG bolt which, unless detected and corrected, "could lead to main landing gear collapse during operation." The AD therefore treats hydrogen embrittlement as a latent material/production defect requiring physical inspection and bolt replacement.

• Targeted inspection trigger. The inspection criterion is concrete and narrow: inspect "the special bolts that attach the MLG retraction actuators and the special bolts that attach the shock absorbers to the MLG assemblies to identify the serial numbers that start with the letters AT or have a supplier code AT" (in accordance with paragraph 3.A. of SB No. 32-020). The AD uses serial number and supplier-code marking as the identification mechanism for the potentially embrittled bolts.

• Remedial action requirement. If the inspection identifies "affected bolts", the AD commands replacement "before further flight" with new bolts "with new part numbers", and references paragraph 3.B. of SB No. 32-020 for the replacement procedure. Thus the AD both mandates removal of identified suspect parts and states that replacements must be new parts with different part numbers.

• Coverage of spares and modification kits. The AD explicitly extends the inspection and replacement requirements to "applicable MLG assemblies held as spares, special bolts held as spares, and modification kits incorporating special bolts held as spares" (inspect per paragraph 4. of SB No. 32-020). This prevents operators from avoiding compliance by simply using older spares later.

• Time-limited compliance. The AD sets a short compliance window: "Within 100 hours time in service or 3 months after 25 October 2007, whichever occurs first." This dual metric (flight hours or calendar time) pushes for relatively rapid action even on low-utilisation aircraft.

• Reliance on a manufacturer service bulletin. The AD does not contain procedural detail; it delegates the inspection and replacement methodology to Pilatus Service Bulletin No. 32-020, specifically paragraphs 3.A, 3.B and 4.

• Cross-reference to another authority. The AD notes "Switzerland FOCA AD HB-2007-382 refers," indicating the Swiss authority's corresponding directive is relevant background and may be part of the global compliance picture for operators and maintenance organisations.

These concepts combine to create a compliance regime that predicates continued safe operation of affected PC-12s on identification and removal of bolts likely to have reduced fatigue life because of hydrogen embrittlement, enforced through an AD that prescribes inspection criteria, remedial replacement and a strict compliance timeframe.

The AD affects a defined set of parties directly and a broader set indirectly. The primary, directly affected parties are operators and owners of Pilatus PC-12, PC-12/45 and PC-12/47 aircraft with Manufacturer Serial Numbers 101 through 749 that are fitted with the enumerated MLG assemblies and special bolts delivered before 31 December 2006, as well as organisations that hold the listed MLG assemblies, bolts and modification kits as spares.

• Aircraft owners/operators. If an operator's aircraft falls within the AD's applicability (model and MSN range) and is equipped with any of the listed MLG assembly part numbers or special bolt part numbers (delivered before 31 December 2006), the operator must arrange the required inspections and replace any affected bolts before further flight. The AD explicitly applies to in-service aircraft: Requirement 1 covers inspection of installed bolts and mandatory replacement if affected. The compliance window is immediate and short (100 hours time in service or 3 months after 25 October 2007).

• Maintenance organisations and licensed maintenance personnel. The AD prescribes inspections "in accordance with paragraph 3.A. of PILATUS PC-12 Service Bulletin (SB) No. 32-020" and replacements "in accordance with paragraph 3.B. of SB No. 32-020." Maintenance organisations will decide the timing, labour allocation and procurement of replacement parts, and must apply the SB procedures (including any specified inspections, torque settings, or part-number verification techniques contained in the SB, though the AD itself does not reproduce those technical steps).

• Parts suppliers and spares managers. The AD explicitly brings into scope "MLG assemblies part number ... delivered before 31 December 2006; and held as a spare. Special bolts part number ... delivered before 31 December 2006; and held as a spare. Modification kit numbers ... delivered before 31 December 2006; and held as a spare." Therefore, any entity holding these items in an inventory in Australia (or responsible for Australian-registered aircraft) must inspect those stocked items per paragraph 4. of Pilatus SB No. 32-020 and replace affected bolts where identified.

• Pilatus (the manufacturer) and CASA. Pilatus is the author of the referenced SB and is the source of the manufacturer's determination of hydrogen embrittlement risk. CASA, represented by its delegate, imposes the regulatory requirement and determines the effective date (25 October 2007).

• Flight crews and operational planners. While the AD does not place obligations directly on pilots, the operational effect is that aircraft with identified affected bolts must not be flown "before further flight" until those bolts are replaced. Flight planners therefore must account for potential downtime.

• Insurers and safety managers. They are indirectly affected because the AD imposes a safety remediation duty that could influence underwriting or safety compliance assessments, but the AD text itself does not address insurance.

Who pays. The text does not state who bears the cost; the directive imposes mandatory inspections and replacement obligations on operators and owners of affected aircraft and spares, implying that those entities will incur labour, parts and downtime costs to comply.

Who decides. The AD delegates the technical method to the manufacturer service bulletin and sets the legal requirement and compliance timing; operators and maintenance organisations decide scheduling and procurement to meet the AD requirements, within the prescribed compliance window.

This AD imposes clear duties and leaves limited discretion. The duties are procedural, time-bound, and conditional upon part identity.

Duties imposed by the AD

• Duty to inspect installed bolts. Requirement 1 instructs operators to "Perform an inspection of the special bolts that attach the MLG retraction actuators and the special bolts that attach the shock absorbers to the MLG assemblies to identify the serial numbers that start with the letters AT or have a supplier code AT; in accordance with paragraph 3.A. of PILATUS PC-12 Service Bulletin (SB) No. 32-020." The duty is to follow the SB procedure to identify potentially affected bolts.

• Duty to replace affected installed bolts before further flight. Requirement 1 continues: "If affected bolts are identified during the above inspection, before further flight, replace the affected special bolts with new bolts with new part numbers; in accordance with paragraph 3.B. of SB No. 32-020." The duty is immediate grounding of an aircraft with identified affected bolts until replacements are installed.

• Duty to inspect spares and kits. Requirement 2 imposes a parallel duty for spares and modification kits: "Perform an inspection of applicable MLG assemblies held as spares, special bolts held as spares, and modification kits incorporating special bolts held as spares in accordance with paragraph 4. of SB No. 32-020." This expands the duty beyond installed configuration to inventory control.

• Duty to replace affected spare bolts. Requirement 2: "If affected bolts are identified, replace the affected special bolts." The AD does not permit retaining affected bolts in inventory; identified spares must be replaced.

• Time-limited compliance. Both duties must be completed "Within 100 hours time in service or 3 months after 25 October 2007, whichever occurs first." This creates an urgent, measurable compliance obligation.

Rights or limited discretion under the AD

• No substantive discretion to defer replacement. The AD requires replacement "before further flight" if affected bolts are identified, so there is no discretion to continue operating until a later maintenance slot.

• Discretion on scheduling and procurement. The AD prescribes what to do and the compliance deadline, but not how the operator organises inspections, what maintenance provider to use, or which authorised supply chain to source replacement bolts from. Those operational choices remain with the operator and maintenance organisation, subject to adherence with the SB procedures.

• Reliance on the Service Bulletin. The AD delegates technical methods to Pilatus SB No. 32-020, giving operators the right to follow the SB steps rather than the AD trying to replicate technical detail. The AD requires adherence to specific SB paragraphs (3.A., 3.B., 4.), which places an implicit duty to obtain and implement the SB.

• No explicit recordkeeping language. The AD does not specify documentary or reporting obligations (except that it becomes effective on a given date and the compliance window). Any recordkeeping or reporting duties would flow from broader maintenance and airworthiness regulation, not from the AD text itself.

Who enforces. The AD is issued by CASA (signed by the Delegate) and becomes legally effective. Enforcement and any penalty regime would be pursuant to the general regulatory framework for airworthiness and aviation safety (the AD itself does not set out enforcement or sanction mechanisms).

In short: the AD creates a short-term, non-discretionary duty to inspect targeted MLG bolts (installed and in spares) for serial/supplier code markers and to replace identified affected bolts before any further flight, with procedural steps delegated to Pilatus SB No. 32-020 and a strict deadline.

The AD itself sets operational requirements and an effective date; it does not specify penalties, fines, or procedural enforcement steps within its text. The instrument is an airworthiness directive issued by the Civil Aviation Safety Authority and signed by the Delegate, and it becomes effective on 25 October 2007. However, the AD text contains no express provision describing contraventions, sanctions, or enforcement mechanisms.

What the AD does provide that bears on enforcement

• Clear mandatory obligations. The AD creates unqualified, mandatory obligations (inspect per SB paragraphs, replace affected bolts before further flight, inspect spares and kits). The presence of explicit "before further flight" and a short compliance window signals CASA's intention that failure to comply is a serious matter for airworthiness enforcement.

• Delegation to service bulletin procedures. The AD requires compliance according to Pilatus SB No. 32-020 (paragraphs 3.A., 3.B. and 4.), which means an enforcement authority will have a concrete technical benchmark to determine whether an inspection or replacement has been performed in accordance with the established procedures.

• Effective date and deadline. The AD becomes effective on 25 October 2007 and requires action within 100 hours TIS or 3 months after that date, creating discrete milestones that an inspector can test against maintenance records, logbooks, and inventory checks.

What the AD does not state

• No specified penalties. The AD text contains no penalties, infringement notices, or civil or criminal sanction descriptions. There is no express provision for mandatory reporting to CASA upon completion of compliance, nor is there a notice of immediate grounding by CASA; instead, the AD requires operators to ground an aeroplane with affected bolts "before further flight" themselves until they comply.

• No explicit enforcement procedure. The AD does not set out how CASA will verify compliance, what notices will be issued for non-compliance, or how remedial enforcement action will proceed.

Operationally, therefore, enforcement of this AD will sit within the general powers and compliance regime that CASA exercises under the Civil Aviation legislation and regulations (not reproduced in the AD text). Enforcement actions, sanctions or prosecutions for non-compliance would rely on those broader statutory powers rather than on the AD text itself. Inspectors and auditors will use the AD's precise applicability, inspection criteria, and compliance timeline as the substantive standard when assessing whether an operator has met their airworthiness obligations.

The AD text explicitly references one external, non-Australian instrument and a manufacturer service bulletin, and implicitly sits within the wider airworthiness regulatory framework; the AD itself does not attempt to restate or modify underlying aviation law.

Direct cross-references in the AD

• Pilatus Service Bulletin No. 32-020. The AD requires inspections and replacements "in accordance with" specific paragraphs of the Pilatus SB No. 32-020 (paragraphs 3.A., 3.B. and 4.). The AD thereby imports the SB's technical procedures as the operative method of compliance. Compliance with the AD therefore requires access to and execution of the SB's prescribed methods. The AD does not reproduce the SB content, it simply references it, meaning that the SB forms a required technical annex for complying with the AD.

• Switzerland FOCA AD HB-2007-382. The AD notes "Note: Switzerland FOCA AD HB-2007-382 refers." This indicates there is a corresponding Swiss Federal Office for Civil Aviation directive. The AD does not elaborate on the content of that foreign AD, but the cross-reference situates the CASA AD within an international regulatory response to the same manufacturer's determination. For operators that are part of transnational fleets or managed outside Australia, the FOCA AD is relevant context.

Implied interactions with the broader regulatory regime

• Interaction with airworthiness and maintenance obligations. As an AD from CASA, this instrument operates within the existing legal framework that imposes airworthiness, maintenance and recordkeeping obligations on aircraft operators and maintenance organisations. Although the AD does not restate those obligations or spell out enforcement, it alters the state of required compliance by imposing a specific, time-limited duty. Non-compliance with the AD would therefore be an element that CASA could treat as a breach of broader statutory duties, although the AD itself contains no penalty clause.

• Spares and inventory control. The AD's inclusion of spares and modification kits (held as spares and delivered before 31 December 2006) interacts with inventory management and parts supply chain legal obligations, including those under airworthiness standards that require parts to be airworthy and correctly documented. The AD effectively requires that previously acceptable spares be physically inspected and remediated where affected.

What the AD does not do

• It does not amend or replace other regulations or statutory instruments. It does not create a new statutory offence, and it does not specify penalties; it is a safety directive that operates in tandem with existing legal and regulatory mechanisms. The AD’s authority flows from CASA’s regulatory powers (not set out in the AD text itself).

Practical implications for cross-border operators

• Operators or maintenance organisations that operate under or interact with multiple national regulators will need to reconcile the CASA AD's requirements and SB references with any corresponding foreign ADs (such as the FOCA AD referenced), but the AD does not provide explicit guidance on reconciling different national technical instructions. The AD's short compliance window and explicit reference to the SB suggest CASA expects alignment with the manufacturer's mitigation steps used internationally.

In sum, the AD imports the manufacturer’s SB as the technical compliance method and references a Swiss AD as related material; it otherwise functions within existing aviation law and regulation, without stating its own enforcement or penalty provisions.

The AD text supplied shows a single issuance context and contains no subsequent amendment entries. The document includes a dated signature line and an effective date, but no record of later modification or replacement. Specific items from the AD that reflect its history:

• Signature and date. The AD is signed "David Villiers, Delegate of the Civil Aviation Safety Authority" and dated "7 September 2007" in the body of the document. This indicates CASA’s administrative action and authorisation preceding the effective date.

• Effective date. The AD states: "This Airworthiness Directive becomes effective on 25 October 2007." The effective date is therefore later than the signature date, reflecting a typical lead-in period between issuance and legal effectiveness.

• No explicit amendments or re-issues shown. The supplied text contains no section labelled "Amendment", "Variation", "Supersedes", or similar, and there are no subsequent entry lines that would indicate the AD was altered after its original issue. There is also no explicit expiry or review date specified in the provided text.

• No incorporation of later SB revisions shown. The AD mandates compliance "in accordance with paragraph 3.A. of PILATUS PC-12 Service Bulletin (SB) No. 32-020" etc., but the AD text does not indicate any allowance for later revisions or amended versions of the SB, nor does it indicate that later SB revisions would automatically satisfy the AD. The AD therefore appears tied to the SB as it stood at the time of issue, absent further documentation.

• Cross-reference to FOCA AD. The note "Switzerland FOCA AD HB-2007-382 refers" is a contemporaneous external reference, not an amendment history. It points to parallel regulatory action elsewhere but does not alter this AD.

If an operator requires confirmation of any later amendment or revocation, the AD text supplied gives no evidence of further changes. The only recorded administrative trace in the provided instrument is the original signing on 7 September 2007 and the stated effective date of 25 October 2007.

The provided AD text contains no litigation history, case citations, or references to judicial review proceedings. There are no named legal disputes, no statements about appeals or notices of legal challenge, and no indication that the AD has been the subject of any court or tribunal decision within the document.

What the AD does record is an administrative signature and dates (signed 7 September 2007, effective 25 October 2007) and a cross-reference to a Swiss FOCA AD, but the document contains no information about any litigation, enforcement proceedings or judicial interpretation. Consequently, based solely on the supplied text, there is no recorded litigation history to summarise.

If a reader requires whether this AD has been the subject of litigation, challenge, or enforcement action that resulted in administrative or judicial decisions, that information is not present in the text and would need to be obtained from external records of CASA enforcement, court databases, or other public records. The AD itself does not disclose or reference such matters.

This AD contains several implementation details and narrow criteria that may produce compliance traps if overlooked. The following items come directly from the AD text and merit particular attention when assessing affected fleet items, inventory and workscopes.

• Narrow serial/supplier-code identification criterion. The inspection mandate is not a visual condition-based inspection alone; it requires identifying "serial numbers that start with the letters AT or have a supplier code AT" (Requirement 1). If maintenance personnel do not check the serial number format or supplier code exactly as stated, they may miss affected bolts. The identification mechanism is discrete and superficial markings matter.

• The "before further flight" trigger. If an affected bolt is found on an in-service aeroplane, the AD requires replacement "before further flight" (Requirement 1). This creates an immediate grounding obligation until replacement bolts are fitted. Operators that fail to recognise this may inadvertently continue to fly an aircraft that is non-compliant.

• Inclusion of spares and modification kits held as spares. Requirement 2 brings into scope spares and modification kits "delivered before 31 December 2006; and held as a spare." Inventory managers must therefore trace part provenance and delivery dates for parts in their stock; simply knowing a part number is insufficient if delivery date or supplier details are not recorded or accessible. The AD requires inspection "in accordance with paragraph 4. of SB No. 32-020," but the AD text itself identifies spares and kits as subject to the same risk and corrective action.

• Applicability tied to delivery date cut-off. The AD applies specifically to MLG assemblies, bolts and modification kits "delivered before 31 December 2006." Parts delivered on or after that date appear outside the AD’s stated scope, but that requires reliable procurement and receipt records to prove. Absent clear records, operators risk treating subject parts conservatively (i.e. inspecting/replacing) or facing compliance ambiguity.

• Multiple part numbers and assemblies enumerated. The AD lists many MLG assembly part numbers (532.10.12.037 through .052, with some gaps) and special bolt part numbers (532.10.12.110, 532.10.12.205, 532.10.12.077, 532.10.12.202) and kit numbers (500.50.12.267, 500.50.12.286, 500.50.12.299). Each part number must be checked against installed and spare records. Omitting any listed P/N could lead to an incomplete compliance action.

• Reliance on an external Service Bulletin. The AD requires actions "in accordance with" specific paragraphs of Pilatus SB No. 32-020. The AD does not reproduce the SB procedures, so maintenance personnel must obtain the SB and confirm that the referenced paragraphs cover the required inspection and replacement steps. If the SB has multiple revisions, the AD does not specify which revision applies; absent careful handling, implementers may inadvertently follow a non-applicable SB version.

• Short compliance window. The AD sets a compliance window of "within 100 hours time in service or 3 months after 25 October 2007, whichever occurs first." For low-utilisation aircraft, the calendar cutoff could force compliance sooner than expected; for high-utilisation aircraft, the hour limit could be reached quickly. Scheduling maintenance windows and ordering replacement parts under that time pressure is a practical challenge.

• Manufacturer-determined defect. The AD's stated hazard arises from Pilatus's determination that "certain main landing gear bolts may be affected by hydrogen embrittlement." The AD does not set out independent testing results or thresholds for what constitutes hydrogen embrittlement; reliance is on the manufacturer's determination and the SB for remedial detail. Implementers should therefore ensure they are following the SB's identification criteria precisely.

• No explicit record/reporting clause in the AD. The AD does not state that operators must report compliance to CASA or maintain specific records for the AD itself. However, as this is a CASA AD, operators should ensure they meet any broader regulatory recordkeeping obligations, because the AD's enforcement would rely on examining maintenance logs and records to verify the inspections and replacements were completed within the mandated timeframe.

• International cross-reference. The AD notes a related Swiss FOCA AD. Operators whose aircraft or parts cross jurisdictions should be cautious about differing procedural requirements in other regulators' ADs and ensure compliance meets the most stringent applicable requirement; the AD itself provides no guidance on reconciling differences.

These "gotchas" are concrete procedural and recordkeeping points that the AD text itself raises. Addressing them requires attention to serial/supplier code verification, part delivery provenance, inventory tracing, timely procurement of replacement bolts, and securing and applying the referenced Pilatus SB paragraphs.

The AD prescribes a discrete compliance pathway; the following step-by-step approach follows the AD text exactly and maps the required actions and deadlines for an operator or maintenance organisation responsible for Australian-registered Pilatus PC-12 aircraft within the applicable MSN range.

1. Confirm applicability. For each aircraft, confirm the model and Manufacturer Serial Number: the AD applies to "All Model PC-12, PC-12/45 and PC-12/47 aircraft, with Manufacturer Serial Number 101 through MSN 749" (Applicability). Next, verify whether the aircraft is "equipped with MLG assemblies and special bolts as listed below" and whether those assemblies/bolts were delivered before 31 December 2006. The AD lists MLG assembly part numbers 532.10.12.037, 532.10.12.038, 532.10.12.041, 532.10.12.042, 532.10.12.043, 532.10.12.044, 532.10.12.047, 532.10.12.048, 532.10.12.049, 532.10.12.050, 532.10.12.051 and 532.10.12.052; special bolt part numbers 532.10.12.110, 532.10.12.205, 532.10.12.077 and 532.10.12.202; and modification kit numbers 500.50.12.267, 500.50.12.286, and 500.50.12.299 (Applicability table). For spares, determine whether any of the enumerated assemblies, bolts or kits are "held as a spare."

2. Obtain and review Pilatus SB No. 32-020. The AD requires inspections and replacements "in accordance with paragraph 3.A.," "paragraph 3.B.," and "paragraph 4." of SB No. 32-020. Obtain the SB and ensure you are referencing the correct edition and those particular paragraphs. The AD does not reproduce the SB instructions; compliance requires following the SB's prescribed inspection methods and replacement procedures.

3. Perform the in-service inspection (Requirement 1). Following paragraph 3.A. of SB No. 32-020, inspect "the special bolts that attach the MLG retraction actuators and the special bolts that attach the shock absorbers to the MLG assemblies" to identify serial numbers that "start with the letters AT" or parts that "have a supplier code AT." Document the inspection findings in the aircraft maintenance records in accordance with standard airworthiness recordkeeping practice.

4. If affected bolts are found on an aircraft, replace before further flight (Requirement 1). If the inspection identifies any bolts marked as affected, replace them "before further flight" with new bolts with new part numbers, "in accordance with paragraph 3.B. of SB No. 32-020." Do not operate the aircraft again until replacements are fitted. Ensure replacement parts meet any additional SB-specified installation or torque procedures, and update maintenance logs with details of parts replaced, batch/serial numbers of replacements, and sign-off by an authorised maintenance certifier.

5. Inspect spares and modification kits (Requirement 2). Identify all inventory items that match the listed MLG assembly part numbers, special bolt part numbers and modification kit numbers and that were delivered before 31 December 2006 and are held as spares. Perform the inspection required "in accordance with paragraph 4. of SB No. 32-020." If the SB's paragraph 4 prescribes particular checks (e.g. serial number verification, supplier code checks), follow those steps exactly.

6. Replace affected spares. If the inspection of spares or kits identifies affected bolts, "replace the affected special bolts" per Requirement 2. Do not return affected spares to service without replacement.

7. Meet the statutory compliance window. Complete Requirements 1 and 2 "Within 100 hours time in service or 3 months after 25 October 2007, whichever occurs first." For operational planning, calculate 100 hours TIS from the next flight or existing Hobbs/airframe time as applicable and schedule inspections and any replacements to meet the earlier of the two deadlines.

8. Maintain records and ensure traceability. While the AD does not specify a reporting form, ensure maintenance records capture the inspection method used (SB paragraph reference), the serial numbers/supplier codes inspected, any affected bolts found, replacements installed (with new part numbers and, where applicable, new serial numbers), dates and times, and certifying engineer details. These records will be the evidence of compliance if CASA audits the operator.

9. Coordinate procurement of replacement bolts. The AD requires replacement with "new bolts with new part numbers" per SB paragraph 3.B. Procurement should verify part numbers, ensure the supplier can provide bolts that are compliant with the SB instructions, and confirm delivery times to meet the compliance deadline. For economies of scale, coordinate across fleet units to procure the exact new part numbers specified.

10. Check related directives. The AD notes "Switzerland FOCA AD HB-2007-382 refers." If the operator has relationships with non-Australian regulators or operates aircraft internationally, confirm whether the FOCA AD or other national ADs impose different or additional steps and ensure compliance with the most restrictive applicable requirement.

11. Implement internal control measures to prevent re-use of affected spares. Since the AD brings spares into scope, implement inventory segregation or tagging for parts inspected and cleared versus parts that are affected and have been removed or replaced. Preventing inadvertent reinstallation of an affected bolt is key to long-run compliance and safety.

12. Treat "before further flight" findings as immediate grounding events. If an inspection reveals affected bolts on an aircraft scheduled for a flight, do not permit the flight until replacement bolts are installed. Ensure the operational control chain (flight dispatch, maintenance control, flight crew) is aware of this immediate effect.

Following these steps , confirming applicability, following the SB instructions for inspection and for replacement, acting within the compliance window, maintaining robust records and ensuring procurement of the correct new part numbers , implements the AD requirements as set out in the text. The AD does not provide additional procedural nuances beyond reference to the SB; compliance requires integration of the SB, accurate inventory and serial/supplier-code verification, and prompt scheduling to meet the AD’s deadlines.