AD/PREMIER/2 - Starter Generator Shimming

The AD revolves around a narrow set of technical and procedural concepts stated in the text. These concepts determine applicability, the required work, acceptable sources of compliance, and the timing:

• Applicability by airframe serial number. The Directive applies to Model 390 aeroplanes with serial numbers RB-1 and RB-4 through RB-149. The text explicitly lists those serial numbers in the Applicability clause. The list excludes RB-2 and RB-3 on its face; the Directive provides no explanation for that omission.

• Specific part numbers. The starter-generators in scope are identified by two manufacturer part numbers: Raytheon Aircraft Company (RAC) P/N 390-389001-0001 and Advance Industries (AI) P/N MG94A-1 (Requirement 1 and Requirement 3). The Directive ties action to these P/Ns as cross-referenced to SB 24-3790 paragraph 3.A.(2).

• Reliance on a service bulletin for detailed identification and procedure. The Directive requires operators to follow RAC Mandatory Service Bulletin SB 24-3790 Issued August 2006 for the inspection procedure (to determine serial number and suffix at paragraph 3.A.(2)) and for the replacement/shimming procedures. The AD does not reproduce the SB technical detail; it mandates the SB as the procedural reference (Requirement 1 and Requirement 2).

• Conditional and staged remedial action. The Directive uses conditional logic: Requirement 1 is an inspection to identify whether the in-service starter-generators match the units specified in SB 24-3790 paragraph 3.A.(2). If none are found, Note 1 states that no further action is required. If affected units are found, Requirement 2 imposes replacement obligations with different timing depending on whether one or both units are affected (Requirement 2.a and 2.b).

• Prohibition on installation as spares. Requirement 3 prohibits installing the specified starter-generators as replacement spares on any aeroplane; this prohibition takes immediate effect after the Requirement 1 inspection (Requirement 3 and Compliance for Requirement 3).

• Acceptance of FAA-approved alternate methods of compliance. The Directive states that later revisions of SB 24-3790 are acceptable if approved by the U.S. Federal Aviation Administration as an AMOC to FAA AD 2007-20-07, and that such revisions will be considered acceptable for compliance with the equivalent requirements of this Directive (Requirement 3). The AD also includes Note 2, which directly references FAA AD 2007-20-07 Amdt 39-15217.

• Time-in-service and calendar time compliance metrics. The AD uses both hours TIS and calendar time for compliance, with the requirement to comply by whichever occurs first. Specific windows are: Requirement 1 within 50 hours TIS or 3 months; replacement sequencing with a 10 hours TIS short window for at least one unit when both are affected, and 200 hours TIS or 12 months for the remaining replacements (Compliance).

• Safety rationale. The Background clause explains that the FAA received reports of a manufacturing error producing improperly shimmed starter-generators, creating a risk of premature starter-generator failure and potentially increased chances of dual starter-generator failure on the same flight. The Directive states this as the reason for requiring inspection and replacement.

These concepts structure who must act, how to identify the affected components, what remedial actions are mandatory, the acceptable compliance paths (including FAA AMOCs), and the timing constraints. The AD ties technical identification and replacement procedures to an external document (SB 24-3790), therefore effective compliance requires access to and application of that service bulletin.

The Directive identifies and therefore affects a defined set of actors directly and several ancillary actors indirectly:

• Owners and operators of Model 390 aeroplanes with serial numbers RB-1 and RB-4 through RB-149. The Applicability clause confines direct regulatory obligations to operators of those specific airframes. Those operators bear the immediate obligation to arrange and complete the inspections and, where required, the replacements within the prescribed windows.

• Maintenance personnel and organisations authorised to perform inspections and replacements under the applicable maintenance regulations. The Requirement 1 inspection calls for determining serial number and suffix as specified in SB 24-3790 paragraph 3.A.(2). The maintenance organisations or certifying engineers who perform that work must follow the SB procedures to identify affected starter-generators reliably.

• Parts suppliers and logistics functions. Requirement 3 prohibits installing specified RAC P/N 390-389001-0001 or AI P/N MG94A-1 units identified in SB 24-3790 paragraph 3.A.(2) as replacement spares after the Requirement 1 inspection. Parts suppliers and aircraft operators’ stores managers will need to ensure stock control and traceability to prevent prohibited installations.

• Regulatory administrators and airworthiness authorities. The AD was issued by a Delegate of the Civil Aviation Safety Authority (CASA), showing the regulator’s role in issuing mandatory directives. CASA or its delegate acts as the issuer and therefore as the deciding authority for the Directive (signature block: David Punshon, Delegate of CASA). The Directive also recognises FAA-issued AMOCs and FAA AD 2007-20-07 for equivalence, which affects how operators and maintenance organisations may choose a compliance path.

• Service bulletin authors and holders. Raytheon’s Mandatory Service Bulletin SB 24-3790 is integral to identifying and remedying the affected starter-generators. Operators and maintainers must obtain and consult the SB to apply the Inspection and Replacement requirements, making the SB’s authors and publishers relevant stakeholders.

Who pays. The Directive does not specify funding or compensation. The text requires inspection and replacement work and a prohibition on certain spares; those actions will typically result in direct costs to operators in the form of man-hours, part replacement, logistics and potential aircraft downtime. The Directive does not allocate costs to manufacturer, supplier, or insurer.

Who decides about alternative compliance. The AD explicitly accepts later SB revisions approved by the FAA as an AMOC to FAA AD 2007-20-07 as acceptable for compliance with the equivalent requirements of this Directive. That creates a decision point: operators may either follow the original SB 24-3790 procedures or rely on later SB revisions, provided those revisions carry FAA AMOC approval (Requirement 3).

Indirectly affected parties. Entities engaged in flight operations planning, aircraft utilisation, and charter or commercial services that depend on Model 390 aeroplanes listed in the Applicability should expect potential operational disruption where inspections and replacements are required within short windows (for example the 10 hours TIS requirement where both units are affected). Insurers and lessors with interests in affected aircraft will also need to track compliance, though the AD does not address contractual responsibilities.

The AD’s defined scope, prescriptive content and timing create concentrated obligations on operators of the listed serial-numbered aeroplanes, and operational and logistical implications for their maintenance providers and parts supply chains.

Duties established by the Directive are specific and time-bound. The document also provides limited rights or exemptions subject to the stated conditions.

Primary duties

• Inspect both left-hand and right-hand starter-generators on each affected aeroplane to determine serial number and suffix, following the identification instructions in paragraph 3.A.(2) of Raytheon Mandatory Service Bulletin SB 24-3790 Issued August 2006 (Requirement 1). The required inspection is explicit about which P/N units to examine: RAC P/N 390-389001-0001 or AI P/N MG94A-1 (Requirement 1).

• If starter-generators specified in paragraph 3.A.(2) of SB 24-3790 are identified during the Requirement 1 inspection, replace those units with properly shimmed starter-generators in accordance with SB 24-3790 Issued August 2006 (Requirement 2). The replacement must follow the procedural and technical guidance in the service bulletin, which the Directive makes operative by reference.

• Follow the staged replacement timing rules in the Directive:

  • If both starter-generators are identified as improperly shimmed: replace at least one affected starter-generator within 10 hours TIS after the Requirement 1 inspection, and replace the other within 200 hours TIS after the effective date or within 12 months after the effective date, whichever occurs first (Requirement 2.a(i) and 2.a(ii), Compliance).
  • If only one starter-generator is identified as improperly shimmed, replace that unit within 200 hours TIS after the effective date or within 12 months after the effective date, whichever occurs first (Requirement 2.b, Compliance).

• Immediately following the Requirement 1 inspection, do not install any starter-generator with RAC P/N 390-389001-0001 or AI P/N MG94A-1 that is specified in paragraph 3.A.(2) of SB 24-3790 as a replacement spare on any aeroplane (Requirement 3 and Compliance).

• Apply the compliance windows as specified: Requirement 1 within 50 hours TIS or within 3 months of the effective date, whichever is first; staged replacement windows as set out above (Compliance).

Rights, exemptions and options contained in the text

• If a starter-generator specified in paragraph 3.A.(2) of SB 24-3790 is not found during the Requirement 1 inspection, no further action is required. This is explicitly stated as Note 1 to Requirement 1. That gives operators a narrow exemption where the in-service parts are shown by the inspection not to match the SB-specified units.

• Later revisions to SB 24-3790 are acceptable where they have been approved by the FAA as an Alternate Method of Compliance to FAA AD 2007-20-07. The Directive treats such FAA-approved SB revisions as acceptable for compliance with the equivalent requirements of this Directive. That provides operators with a path to use updated technical guidance without seeking further CASA-specific approvals, provided the FAA has granted AMOC status (Requirement 3).

• The Directive does not set out any discretionary alternatives within its own text. Alternative compliance or deviations would therefore need to rely on the FAA AMOC mechanism referenced in the AD or on any CASA processes outside the text; the AD itself neither creates nor describes a CASA AMOC process.

Record-keeping and technical conformity

• The AD requires that replacements be carried out "in accordance with SB 24-3790", which implies that the documentation and technical standards in that bulletin must be followed closely. The Directive is prescriptive about the method (use SB 24-3790) and the parts (properly shimmed starter-generators). The AD does not specify particular records to be kept, but following standard maintenance regulatory practice, the inspection and replacement actions would be expected to be entered into the aircraft maintenance log and records to show compliance with the Directive.

Timing obligations

• The Directive uses granular, short windows for some compliance items (notably the 10 hours TIS window for at least one replacement where both units are affected), which creates immediate scheduling obligations for operators once affected units are identified (Compliance).

The AD therefore creates a clear set of mandatory duties (inspect, identify, replace, and prohibit installation as spare), a narrow exemption (no action if SB-specified units are not found), and an explicit compliance pathway via FAA-approved SB revisions. The text contains no flexibility beyond those stated options.

The Directive text itself does not include express penalty provisions or a detailed enforcement regime. The AD sets out mandatory actions and effective dates, but it does not specify fines, suspension mechanisms, or criminal penalties within its own wording.

What the AD does state about enforcement-relevant points

• Issuer and legal provenance. The AD is signed by the Delegate of the Civil Aviation Safety Authority, David Punshon, and is presented as a directive from CASA. The presence of the CASA delegate’s signature and the form of the document indicate it is an enforceable regulatory airworthiness instrument within CASA’s administrative framework, but the AD text does not recite the statutory enforcement powers, penalty schedules, or notice-and-penalty procedures that CASA may invoke under broader aviation statutes and regulations.

• Mandatory compliance windows. The Directive prescribes mandatory compliance times (for example Requirement 1 within 50 hours TIS or 3 months, and the staged replacement windows for Requirement 2). These time-bound requirements can be used by an enforcing authority to assess compliance.

• Reference to FAA AD. The Directive expressly references FAA AD 2007-20-07 and accepts FAA-approved AMOCs to equivalent FAA AD requirements. That linkage may affect cross-jurisdictional enforcement and acceptance of compliance evidence, but the Directive itself does not define how CASA will treat FAA findings or certificates beyond allowing FAA-approved SB revisions as acceptable for compliance.

What the AD does not do

• No penalties are stated in the AD. The document does not name monetary fines, licence suspensions, certificates at risk, or other punishments. It does not describe appeal rights, review procedures, or administrative enforcement steps available to CASA or to regulated parties.

• No enforcement process is described. The AD does not explain how compliance will be monitored, audited, or validated by CASA, nor does it prescribe timelines for record submission or inspection by CASA.

Implications for operators and maintainers

• Although the AD is silent on specific sanctions, operators should treat the Directive as a mandatory regulatory requirement from CASA. Failure to comply with mandatory airworthiness directives typically affects the aircraft’s continued fitness for service and could expose operators to regulatory action under the wider statutory framework that governs aviation safety. The AD itself, however, does not set out those downstream enforcement mechanisms or penalties.

• The practical enforcement risk to an operator will therefore depend on broader CASA enforcement policies and aviation safety regulations outside the AD text. The AD provides the substantive safety requirement and timing; enforcement and penalties, where relevant, are to be found in CASA’s broader regulatory instruments and statutory powers, which are not reproduced in this Directive.

In short, the Directive prescribes mandatory corrective action and timing, but the text provided does not include an independent penalty schedule or a description of enforcement procedures. Operators should assume these obligations are enforceable under CASA’s authority, but must look to CASA’s broader statutory framework for the specific enforcement mechanisms and penalties.

The Directive explicitly cross-references FAA regulatory material and a manufacturer service bulletin as part of its compliance architecture, and by making those references it creates points of interaction with external instruments. The AD itself does not recite domestic aviation statutes or maintenance rules beyond being issued by CASA’s delegate, so the following interactions are limited to the material contained in the Directive.

• Interaction with Raytheon Mandatory Service Bulletin SB 24-3790 (Issued August 2006). The Directive makes SB 24-3790 the operative technical document for identification (paragraph 3.A.(2) for serial numbers and suffixes) and for the replacement/shimming procedures (Requirement 2). That interaction requires operators to consult and apply SB 24-3790 in order to comply with the Directive. The AD does not replicate SB technical content, so effective compliance depends on obtaining and following the SB.

• Acceptance of FAA AMOC and FAA AD 2007-20-07. The Directive states that later revisions of SB 24-3790 approved by the United States Federal Aviation Administration as an Alternate Method of Compliance to FAA AD 2007-20-07 are acceptable for compliance with the equivalent requirements of this Directive. The AD thus interacts with FAA regulatory decisions by recognising FAA-approved AMOCs as acceptable alternatives. It also references FAA AD 2007-20-07 Amdt 39-15217 in Note 2. This creates a cross-jurisdictional compliance path: operators may follow SB revisions that the FAA has approved as AMOCs without seeking separate CASA amendment provided the FAA approval exists and is applicable.

• Interaction with broader airworthiness and maintenance obligations. The AD does not explicitly cite the domestic maintenance or continuing airworthiness regulations, but as an airworthiness directive issued by CASA it operates within that wider regulatory framework. The AD imposes specific corrective measures to preserve airworthiness; compliance would typically be recorded in the aircraft’s maintenance records consistent with general maintenance and continuing airworthiness laws, even though such recording obligations are not spelled out in this Directive.

• Parts control and supply chain implications. Requirement 3 prohibits the installation of certain starter-generators as replacement spares on any aeroplane after the Requirement 1 inspection. That prohibition interacts with obligations of parts providers and operators to control and approve spare parts in maintenance processes. The AD therefore interfaces with contractual and regulatory regimes governing parts sourcing and traceability.

Limits in the Directive’s cross-references

• The Directive’s only external legal/regulatory references in the text are the manufacturer service bulletin SB 24-3790 and the FAA AD and AMOC process. The AD does not reference other domestic regulations, such as specific Civil Aviation Regulations or Manuals of Standards. Consequently, readers must treat those broader regulatory interactions (for example record-keeping and enforcement) as existing outside the text of the AD and governed by CASA’s general regulatory instruments.

• The AD does not create or describe a domestic AMOC mechanism; it only recognises FAA-approved SB revisions as acceptable. If an operator seeks another alternative method of compliance without FAA AMOC approval, the AD contains no procedural text describing how CASA will consider such alternatives.

Summary

The Directive interacts substantively with the manufacturer service bulletin and with FAA regulatory determinations, and it embeds those external instruments into CASA’s mandatory requirement. It does not set out how it dovetails into the broader domestic enforcement or maintenance-rule architecture; those interactions are implicit and governed by CASA’s broader statutory and regulatory framework rather than by the AD text itself.

The AD text provides a minimal amendment trail within the document. From the material contained in the Directive:

• Single issuance and effective date. The document as supplied is identified as AD/PREMIER/2, dated 12/2007 DM, with the written signature block dated 10 October 2007 and an effective date stated as 7 November 2007 (Compliance and signature block). The AD therefore appears to be a single instrument issued in October 2007 and becoming effective on 7 November 2007.

• Internal notations and identifiers. The AD carries the identifier AD/PREMIER/2 and repeats the identifier several times across the document headings (for example the header rows that show "AD/PREMIER/2 AD/PREMIER/2" and multiple lines repeating "AD/PREMIER/2" and "12/2007 DM"). These appear to be formatting or administrative markers indicating Directorate, sequence number and month/year of the directive. The AD does not include separate amendment entries or a history of revisions within the text provided.

• Reference to later revisions of SB 24-3790. The Directive includes a mechanism to accept later revisions of the Raytheon SB 24-3790 if those revisions are approved by the FAA as an AMOC to FAA AD 2007-20-07. This is not an amendment to the AD itself, but it creates a forward-looking qualification allowing subsequent SB revisions (approved by FAA as AMOCs) to serve as acceptable compliance material for the AD’s equivalent requirements. The exact text is: "Later revisions of the above SB, approved by the United States Federal Aviation Administration (FAA) as an Alternate Method of Compliance (AMOC) to FAA AD 2007-20-07, is/are considered acceptable for compliance with the equivalent Requirements of this Directive." That language supplies a de facto mechanism for updated technical guidance to be used without formal textual amendment of the AD.

• No recorded subsequent amendments in the provided text. The supplied AD does not list any later amendments, superseding ADs, or revocation entries. There is no amendment history table or notes indicating that the AD has been modified since issuance. If CASA later amended the AD, those amendments are not present in the current text provided.

• Cross-reference to FAA AD 2007-20-07. The AD cites FAA AD 2007-20-07 Amdt 39-15217 in Note 2. The inclusion of that FAA AD as related material functions as a contextual cross-reference rather than an amendment. The AD does not report changes to its own text resulting from the FAA AD.

Practical consequence for readers

• To determine whether any amendments or superseding directives exist, operators and maintainers must consult CASA’s current AD database or other official CASA publications, because the AD as provided does not include any subsequent amendment history. The AD provides only its original issuance and effective date and allows for FAA-approved SB revisions as acceptable compliance alternatives, but it contains no follow-on amendment log.

The Directive as provided does not include, cite or mention any litigation, case law, administrative appeals, or judicial review relating to its contents or its issuance. There are no judicial or tribunal citations in the text, and the document does not report any legal challenges or outcomes.

What the text does reference

• The AD references FAA AD 2007-20-07 Amdt 39-15217 and the FAA AMOC process for SB revisions. Those references are regulatory cross-references, not litigation citations, and the AD does not report any disputes or court decisions arising from the FAA AD or the SB.

What the absence of litigation references means in practice

• The AD does not itself document any legal proceedings or appeals arising from the directive. If litigation, appeals or enforcement actions have occurred relating to this AD, they are not recorded in the provided text. Any practitioner seeking case law or precedential material concerning this AD will need to search external litigation databases, tribunal records or CASA enforcement records because the AD contains no litigation history.

• The Directive’s silence on litigation should not be read as evidence that no proceedings occurred. It simply means the instrument does not record, summarise or reference any litigation. The AD is a compliance mandate, not a repository of disputes or adjudicative history.

For readers requiring legal precedent, challenge outcomes, or judicial interpretation, further research beyond the AD text will be necessary because no litigation history is contained in the source document.

The Directive contains a number of technical and procedural details that can trap unwary operators or result in inadvertent non-compliance if not followed precisely. The following points are drawn directly from the AD text and explain how those details function operationally.

• Applicability is narrowly serial-numbered and omits some numbers. The AD applies to Model 390 aeroplanes with serial numbers RB-1 and RB-4 through RB-149. This explicit listing excludes RB-2 and RB-3 on its face. Do not assume applicability by model alone; the serial numbers govern whether the AD applies to a specific aeroplane (Applicability). Operators should verify the aircraft serial number carefully.

• Reliance on SB paragraph 3.A.(2) for identification. The Directive requires identification of affected starter-generators by determining serial number and suffix as specified in paragraph 3.A.(2) of SB 24-3790. The AD does not reproduce that paragraph, so compliance requires access to and correct interpretation of that specific SB paragraph. If maintenance teams inspect parts without consulting paragraph 3.A.(2), they risk misidentifying whether an item falls within the AD scope (Requirement 1 and Note 1).

• Note 1 grants a narrow exception. If an in-service starter-generator specified in paragraph 3.A.(2) of SB 24-3790 is not found during the Requirement 1 inspection, the AD states "no further action is required." That is an immediate and narrow relief mechanism, but it depends on the inspection being conducted in compliance with SB 24-3790 identification criteria. Misreading the SB could lead to unnecessary replacements or to missing an affected unit.

• Staged replacement sequencing can be confusing. For the case where both starter-generators are identified as improperly shimmed, the AD requires replacement of at least one affected starter-generator within 10 hours TIS after the Requirement 1 inspection, and replacement of the other within 200 hours TIS after the effective date or 12 months after the effective date, whichever is first. The short 10-hour TIS window for the first replacement can create immediate operational pressure and requires rapid parts sourcing, scheduling and recordation (Requirement 2.a and Compliance). Operators should not treat the 10-hour interval as aspirational.

• Immediate spare prohibition. The prohibition on installing certain RAC P/N 390-389001-0001 or AI P/N MG94A-1 starter-generators specified in SB 24-3790 paragraph 3.A.(2) as replacement spares takes effect "Immediately following the Requirement 1 inspection" (Requirement 3 and Compliance). Practically, if the Requirement 1 inspection has been performed on a fleet, affected spares already in stores may need to be quarantined or segregated immediately to avoid prohibited installation.

• Different compliance windows use "whichever occurs first". Many of the compliance entries use the form "within X hours TIS after the effective date of this Directive or within Y months after the effective date of this Directive, whichever occurs first." This means operators must track both flight-hours and calendar time and comply once either threshold is reached (Compliance). Focusing only on calendar time or only on hours TIS can lead to late compliance.

• Acceptable SB revisions require FAA AMOC approval. The AD allows later revisions of SB 24-3790 to be used if they are approved by the FAA as an AMOC to FAA AD 2007-20-07. The AD does not treat other approvals as acceptable. Therefore, if an operator obtains an updated SB revision that lacks an FAA AMOC designation, the Directive does not treat that revision as acceptable for compliance without further FAA approval (Requirement 3).

• Parts identification and traceability obligations implicit but not spelled out. The AD requires part-number-based inspections and prohibits the installation of specific P/Ns if they match SB paragraph 3.A.(2). While the AD does not lay down explicit record-keeping steps, operators must ensure strong parts traceability and maintenance record entries to demonstrate compliance.

• Short lead times for some actions can create logistical bottlenecks. The 10-hour TIS replacement requirement for at least one starter-generator when both are affected is a tight operational window. Ensuring availability of properly shimmed replacement units, authorised maintenance personnel, and downtime scheduling within that period will be necessary.

• The AD does not say who pays. The Directive prescribes the actions but does not allocate any cost burden to the manufacturer, supplier or other parties (Background and Requirements). The financial impact of inspection, removal and replacement lies with the operator unless other contractual or warranty arrangements outside the AD apply.

• No domestic AMOC mechanism is included. The AD specifically accepts FAA-approved SB revisions as AMOCs, but it does not create or describe a domestic CASA AMOC alternative in the text. If an operator seeks another method of compliance that is not FAA-approved, the AD gives no procedural guidance on whether or how CASA will consider that alternative (Requirement 3).

These "gotchas" flow directly from the AD’s specific wording. Operators should ensure maintenance teams access SB 24-3790 paragraph 3.A.(2), track both TIS and calendar time, prepare for rapid replacement where required, and be careful about parts control and spares usage.

Compliance with this Directive requires a combination of correct technical identification, prompt scheduling of inspections and replacements, parts management, and record-keeping. The following steps, grounded in the AD's text, describe a practical compliance approach.

1. Confirm applicability

• Verify the aircraft’s serial number. The AD applies only to Model 390 aeroplanes with serial numbers RB-1 and RB-4 through RB-149 (Applicability). If your aircraft is not listed, the AD does not apply as written.

2. Obtain Raytheon Mandatory Service Bulletin SB 24-3790 (Issued August 2006)

• The AD mandates inspection and replacement actions "as specified in paragraph 3.A.(2) of RAC Mandatory Service Bulletin SB 24-3790 Issued August 2006" and requires replacement "in accordance with SB 24-3790." Obtain the bulletin and, where applicable, any later revisions that have FAA approval as an AMOC. Use paragraph 3.A.(2) as the authoritative part-identification source for serial numbers and suffix letters (Requirement 1 and Requirement 2).

3. Schedule and perform Requirement 1 inspection within the stated window

• Requirement 1 must be completed within 50 hours TIS after the AD’s effective date or within 3 months after the effective date, whichever occurs first (Compliance). Plan for the inspection to be performed by authorised maintenance personnel in accordance with SB 24-3790 identification methods. The inspection covers both left-hand and right-hand starter-generators of the aircraft and requires determining serial number and suffix per SB paragraph 3.A.(2) (Requirement 1).

4. Record the inspection outcome and apply Note 1

• If the inspector does not find any starter-generator specified in paragraph 3.A.(2) of SB 24-3790 during Requirement 1, the AD provides that no further action is required (Note 1). Record this finding clearly in the aircraft maintenance records to demonstrate compliance. If a specified unit is found, proceed to replacement steps immediately.

5. If specified units are found, comply with Requirement 2 replacements

• Replace affected starter-generators with properly shimmed units in accordance with SB 24-3790 Issued August 2006 (Requirement 2). Follow the SB’s replacement or shimming procedures exactly as the AD makes those the operative method.

• If both starter-generators are identified as improperly shimmed: a) Replace at least one affected unit within 10 hours TIS after the Requirement 1 inspection (Requirement 2.a(i) and Compliance). b) Replace the other affected unit within 200 hours TIS after the effective date or within 12 months after the effective date, whichever occurs first (Requirement 2.a(ii) and Compliance).

• If only one starter-generator is identified as improperly shimmed: a) Replace that affected unit within 200 hours TIS after the effective date or within 12 months after the effective date, whichever occurs first (Requirement 2.b and Compliance).

6. Immediately apply Requirement 3 spare prohibition

• Following the Requirement 1 inspection, do not install any starter-generator with RAC P/N 390-389001-0001 or AI P/N MG94A-1 that is specified in paragraph 3.A.(2) of SB 24-3790 as a replacement spare on any aeroplane (Requirement 3 and Compliance). Quarantine or otherwise control inventory of spares to ensure no prohibited installations occur. Update parts control records and notify stores personnel of the prohibition.

7. Where available, use FAA-approved SB revisions

• If a later revision of SB 24-3790 exists that has been approved by the FAA as an AMOC to FAA AD 2007-20-07, that revision is considered acceptable for compliance with the equivalent requirements of this Directive (Requirement 3). If using a later revision, retain FAA AMOC documentation and record it with the maintenance entries to support the compliance method chosen.

8. Maintenance record entries and traceability

• Although the AD does not prescribe a specific record form, normal maintenance practice requires logging the Requirement 1 inspection, any replacements under Requirement 2, and the actions taken to comply with Requirement 3. Include references to SB 24-3790 paragraphs used for identification, the dates, TIS at the time of inspection and replacement, part numbers and serial numbers installed and removed, and the name and authorisation of the maintenance personnel or organisation that performed the work.

9. Plan for supply chain and operational impacts

• The 10 hours TIS window for the first replacement where both units are affected is short. Coordinate parts procurement (or borrow agreements), technician availability and aircraft downtime in advance when schedules or fleet checks make this likely. If anticipated shortages of properly shimmed replacement starter-generators exist, liaise with parts suppliers and Raytheon to source acceptable spares.

10. Retain evidence of compliance for audit or enforcement

• Save SB copies, inspection records, replacement work orders, parts traceability certificates and, where used, FAA AMOC approvals. As the AD does not specify enforcement procedures, maintaining a clear audit trail will help demonstrate compliance if CASA or another authority queries the aircraft’s airworthiness.

11. Verify ongoing conformity for future maintenance

• Ensure that maintenance planning removes the prohibited P/Ns from approved spare lists for the affected fleet and applies the AD’s prohibitions across the operator’s maintenance control system. For any future overhauls or parts replacements, check the installed starter-generators against SB 24-3790 paragraph 3.A.(2) to avoid reintroduction of prohibited units.

12. If in doubt, consult CASA or authorised technical representatives

• The AD accepts FAA-approved SB revisions as acceptable compliance methods; it does not describe other alternative compliance routes. If an operator believes another method is necessary, or if documentation ambiguity exists, consult CASA or an authorised CASA delegate for clarification.

Following the steps above will align an operator’s actions with the AD’s explicit requirements: accurate identification under SB 24-3790 paragraph 3.A.(2) (Requirement 1), timely replacement where affected units are found (Requirement 2), immediate prohibition on installation of identified P/N spares following inspection (Requirement 3), and use of FAA-approved SB revisions where available (Requirement 3). Keep a contemporaneous record of inspection and replacement dates, TIS values, part serial numbers and the SB revision used for auditability.