This AD is structured around a small set of operational concepts: applicability by serial-number group; identification of a specific component by part number, serial-number range and modification status; inspection and modification mandated by reference documents; conditional requirements tied to logbook or visual evidence; prohibitions on installation and incorporation; and time-critical compliance windows.

1. Applicability by serial-number groups. The AD divides the Model 1900D fleet into three groups by serial numbers: Group 1 UE-1 to UE-265, Group 2 UE-266 to UE-388, Group 3 UE-389 to UE-410 (Applicability). Different groups attract slightly different requirements. Group 1 is subject to the fullest set of checks and conditional requirements; Group 2 has affirmative sync wire shield modification required; Group 3 is primarily within the general inspection and replacement-part prohibition regime.

2. Component and serial-number targeting. The AD targets KGS Electronics AC Inverter P/N SPC-10(PW) with serial numbers 306 through 803. Requirement 1 directs operators to inspect to determine if that specific P/N and S/N range is installed and whether it is identified as Mod 2DD. The technical identity of the inverter, including both part number and serial-number range, is the trigger for further mandatory action.

3. Modification status as a pass/fail criterion. Whether a device is identified as Mod 2DD determines whether additional work is required. If it can be “positively shown” by logbook or visual inspection that Mod 2DD is already incorporated, Requirement 2 does not apply (Requirement 1). The logbook or visual-identification pathway is explicitly accepted as a means to avoid needless modification.

4. Layered conditionality tied to an FAA STC. For Group 1 only, the AD requires an inspection to determine if FAA STC SA00245WI-D has been or is installed (Requirement 3). If that STC has been installed, a different modification is mandated: the AC inverter synchronisation wire shield modification (Requirement 4). The AD then prohibits incorporation of that FAA STC into Group 1 aeroplanes unless the required sync-wire modification has been done (Requirement 7).

5. Reference to external technical documents as mandated compliance method. The AD mandates compliance with the Accomplishment Instructions section of Raytheon Aircraft Service Bulletin SB 24-3215 Rev. 1 June 2001 and the Model 1900D Airliner Maintenance Manual (AMM) for both inspection and modification tasks (Requirements 1-5). That is the AD’s chosen compliance technique: require operators to follow manufacturer/approved maintenance instructions rather than to prescribe alternative technical procedures.

6. Scheduling approach combining calendar deadlines and “before further flight” requirements. The AD uses fixed calendar deadlines (before 21 October 2003 for certain inspections and for the Group 2 sync-wire modification) and immediate operational cut-offs (modifications required “before further flight” after a qualifying inspection) to prioritise safety-critical work without grounding the fleet pending inspection. The prohibitions (Requirements 6 and 7) are effective as of the AD’s effective date, 17 April 2003 (Compliance).

7. Cross-reference to FAA regulatory action. The AD notes that FAA AD2003-04-26 Amdt 39-13075 refers, aligning CASA’s directive with FAA findings and actions. The Background explicitly records FAA reporting of nine incidents of inverter shutdown associated with the KGS inverters in the specified serial-number range (Background).

These core concepts shape how operators allocate maintenance effort, how maintenance records are used to limit work, and how parts sourcing and STC incorporation are constrained by the AD.

Primary regulated parties are operators and maintainers of Beechcraft Model 1900D aeroplanes falling in the serial-number ranges listed by the AD: Group 1 (UE-1 to UE-265), Group 2 (UE-266 to UE-388) and Group 3 (UE-389 to UE-410) (Applicability). Those operators must inspect the AC inverter(s) identified by P/N and serial number range, and perform modifications as specified. The AD’s obligations therefore fall on those responsible for continuing airworthiness and maintenance,aircraft operators, maintenance organisations and certifying staff who perform or approve maintenance per the Model 1900D Airliner Maintenance Manual and the referenced Raytheon Service Bulletin (Requirements 1-5).

Maintenance providers are affected because the AD requires technical actions to be carried out “in accordance with the Accomplishment Instructions section of Raytheon Aircraft Service Bulletin SB 24-3215, Rev. 1, June 2001” and with the Model 1900D AMM (Requirements 1-5). Those documents prescribe how inspections and modifications must be performed. The AD also establishes record-keeping and evidentiary pathways: the operator may use the aeroplane logbook or visual inspection to “positively show” prior incorporation of Mod 2DD or that FAA STC SA00245WI-D has never been installed, in which case certain requirements do not apply (Requirements 1 and 3). This places a practical premium on accurate logbook entries and clear visual identification by maintenance personnel.

Parts suppliers and installers are constrained by the AD’s prohibitions: any KGS Electronics AC inverter P/N SPC-10(PW) with S/N 306-803 not identified as Mod 2DD “may not be installed on any aeroplane as a replacement part” (Requirement 6). Suppliers who hold inventories of such inverters will be affected because these items are barred from installation unless Mod 2DD is confirmed. Similarly, incorporation of FAA STC SA00245WI-D into Group 1 aeroplanes is prohibited unless the sync wire shield modification required by Requirement 4 is accomplished (Requirement 7).

Regulatory actors within CASA and delegated signatories are the decision-makers who issued and enforce the AD; the AD itself is issued by a CASA delegate under subregulation 39.1(1) of CAR 1998, and the document lists the delegate’s signature and dates (opening paragraph; signature block). The AD’s effective date (17 April 2003) fixes when prohibitions in Requirements 6 and 7 apply and when timelines commence for inspections and modifications (Compliance).

Finally, the AD references FAA action (FAA AD2003-04-26) and an FAA STC (SA00245WI-D). Owners, operators and maintainers that interact with FAA STCs, or operate under cross-jurisdictional regulatory environments, will need to track both CASA and FAA requirements because the AD conditions the incorporation of the FAA STC on accomplishment of AD-required modifications (Requirements 3, 4 and 7).

The AD establishes specific duties for operators and maintainers and conditional rights to avoid duplicative work if evidence shows prior compliance.

Principal duties:

• Inspect specified AC inverters to determine whether KGS Electronics AC Inverter P/N SPC-10(PW), S/N 306-803, is installed and is identified as Mod 2DD, following Raytheon SB 24-3215 Rev. 1 (Requirement 1). This inspection must be completed before 21 October 2003 for Requirements 1, as stated in the Compliance section.
• If the inspection shows the inverter present is not identified as Mod 2DD, accomplish the AC inverter modification per the Accomplishment Instructions of SB 24-3215 Rev. 1 and the Model 1900D AMM. That work must be done “before further flight” after the inspection (Requirement 2).
• For Group 1 aeroplanes, inspect to determine whether FAA STC SA00245WI-D is or has been installed, again per the SB (Requirement 3). That inspection must be completed before 21 October 2003 (Compliance).
• If the FAA STC is found to be installed on a Group 1 aeroplane, accomplish the sync wire shield modification per the SB and AMM before further flight after the inspection (Requirement 4).
• For Group 2 aeroplanes, accomplish the AC inverter sync wire shield modification per the SB and AMM before 21 October 2003 (Requirement 5).
• Do not install, as replacement parts, any KGS SPC-10(PW) with S/N 306-803 that are not identified as Mod 2DD (Requirement 6). This prohibition is effective as of the AD’s effective date, 17 April 2003 (Compliance).
• Do not incorporate FAA STC SA00245WI-D on any Group 1 aeroplane unless Requirement 4’s AC inverter modification has been accomplished (Requirement 7). This prohibition is effective as of the AD’s effective date (Compliance).

Conditional rights and evidentiary relief:

• The AD explicitly allows operators to avoid certain modifications if they can “positively show” by checking the aeroplane logbook or by visual inspection that Mod 2DD has already been installed, in which case Requirement 2 does not apply (Requirement 1). Similarly, if logbook or visual evidence shows FAA STC SA00245WI-D has never been installed on a Group 1 aeroplane, Requirement 4 is not applicable (Requirement 3). Those provisions give operators a compliance pathway based on documentary or physical evidence, thereby reducing redundant maintenance where reliable records or markings exist.

Method-based duties:

• The AD prescribes specific technical documents as the method by which duties must be accomplished: Raytheon Aircraft Service Bulletin SB 24-3215 Rev. 1 (June 2001) and the Model 1900D AMM. The duty is not merely to cure the unsafe condition in concept; it is to perform the particular inspection and modification instructions in the referenced documents (Requirements 1-5).

Temporal duties:

• Some duties are immediate and operationally critical in their timing: Requirement 2 and Requirement 4 require completion “before further flight” after the disqualifying inspection. Other duties are scheduled by date: Requirements 1, 3 and 5 must occur before 21 October 2003. Requirements 6 and 7 are effective immediately as of the AD’s effective date.

The AD does not enumerate administrative rights such as application for exemptions or extensions within the text provided. The AD is issued under CASA’s statutory authority (subregulation 39.1(1) CAR 1998), which is the legal basis for imposing these duties (opening paragraph). The AD’s language creates compliance obligations designed to mitigate the risk of AC inverter shutdowns documented in the Background.

The AD supplies mandatory technical requirements and deadlines but does not in the text set out specific monetary penalties or enforcement procedures. The AD is issued under the authority of subregulation 39.1(1) of the CAR 1998 (opening paragraph), which provides the regulatory basis for the CASA delegate’s action. By issuing the AD the delegate imposes prescriptive maintenance and parts-use constraints that operators must follow; non-compliance would mean the aeroplane is not in conformity with the AD and thus not compliant with the continuing airworthiness directions in this instrument.

Enforcement in practice will be through CASA’s regulatory framework under the CAR 1998, but this AD text does not specify the enforcement mechanisms, penalty schedules or administrative processes for non-compliance. The AD creates legally binding obligations to perform specified inspections and modifications at the stated times and to observe the prohibitions on installation and STC incorporation (Requirements 1-7; Compliance). As such, an aeroplane that fails to meet the AD’s requirements will not have satisfied the AD’s mandated continuing airworthiness measures and may thereby be subject to CASA action under other provisions of the CAR 1998, which the AD references as its statutory basis.

Operationally relevant enforcement signals in the AD include:

• Time-limited requirements: inspections before a specified calendar date (before 21 October 2003 for Requirements 1, 3 and 5) and modifications before further flight after inspection (Requirements 2 and 4). The AD sets deadlines that, once passed, mean the operator has failed to achieve the prescribed mitigations within the stipulated period.
• Immediate prohibitions: as of the AD’s effective date (17 April 2003) certain installations and incorporations are expressly disallowed (Requirements 6 and 7). This creates a bright-line operational constraint for parts procurement and for STC incorporation decisions.

The AD’s Background describes nine FAA-reported incidents where electrical noise caused AC inverter shutdowns, with consequences including loss of EFIS, RMI and, in some aeroplanes, engine torque indication. The safety consequences described (loss of flight instruments during critical phases) are the operational risks the AD seeks to mitigate. Enforcement therefore serves the safety purpose articulated in the Background, and CASA’s issuance of the AD deploys its regulatory tools to compel remedial work.

For practitioners advising operators, the omission of specific penalties in the AD text means that the likely enforcement path is prosecution or administrative action under the CAR 1998’s general enforcement regime rather than under this AD’s own text. The AD nevertheless creates obligations that form part of an aeroplane’s required continuing airworthiness state until satisfied.

The AD is an administrative instrument issued under subregulation 39.1(1) of the CAR 1998, so it operates within the Civil Aviation Regulations framework (opening paragraph). That statutory origin means the AD sits in the regulatory architecture that governs continuing airworthiness in Australia.

Cross-reference to FAA regulatory action and STC:

• The AD explicitly references FAA AD2003-04-26 Amdt 39-13075 (Note). The Background reports that the FAA received nine reports of inverter shutdowns and the AD aligns with FAA action by citing the referenced FAA AD. The AD also conditionally regulates FAA Supplemental Type Certificate SA00245WI-D: for Group 1 aeroplanes the AD requires inspection to determine if that STC has been installed and mandates sync wire shield modification where it has been installed (Requirements 3 and 4). Further, it forbids incorporation of that FAA STC into any Group 1 aeroplane unless Requirement 4 has been accomplished (Requirement 7). Thus the CASA AD conditions the domestic permissibility of an FAA STC on compliance with CASA-prescribed technical mitigations.

Interaction with manufacturer and maintenance materials:

• The AD requires compliance with the Accomplishment Instructions of Raytheon Aircraft Service Bulletin SB 24-3215 Rev. 1 (June 2001) and with the Model 1900D Airliner Maintenance Manual (AMM) for the inspections and modifications (Requirements 1-5). Those documents are not themselves law but are mandated by the AD as the method for compliance. Hence, the AD converts manufacturer-approved procedures into regulatory obligations under Australian law.

Parts supply and installation rules:

• Requirement 6 prohibits installation of any KGS SPC-10(PW) with S/N 306-803 that is not identified as Mod 2DD as a replacement part. That prohibition interacts with supply-chain and installation practice: parts that might be acceptable under other regulatory regimes or in other jurisdictions may be barred from use in Australian-registered aeroplanes by the AD once its effective date passes.

Operational acceptance and maintenance records:

• The AD permits operators to rely on the aeroplane logbook or visual inspection to “positively show” that Mod 2DD is already incorporated or that the FAA STC has never been installed (Requirements 1 and 3). That creates an interaction between record-keeping statutory obligations and the AD: the accuracy and completeness of logbook entries are the factual basis for avoiding further mandated work. Where record-keeping laws or maintenance record standards apply, they will affect the ability of an operator to claim exemption under these evidentiary pathways.

Temporal sequencing and regulatory coordination:

• The AD’s compliance timetable (inspections before 21 October 2003; some mods before further flight; prohibitions effective 17 April 2003) interacts with scheduling obligations and operational certification. Operators must sequence inspections and any required modifications in a manner consistent with other regulatory obligations such as maintenance schedules, airworthiness directive compliance registries, and operational reporting.

No statutory amendments or alternative regulatory mechanisms are cited within the AD itself beyond its statutory issuance authority and the FAA references. The AD thereby functions as a point of regulatory coordination: it imports FAA findings and prescriptions and converts select manufacturer instructions into mandatory Australian requirements under the CAR 1998.

The AD text supplied does not record any subsequent amendments to AD/BEECH 1900/39 4/2003 within this document. The document itself specifies that it adopts Raytheon Aircraft Service Bulletin SB 24-3215, Rev. 1, dated June 2001, for its technical accomplishment instructions (Requirements 1-5). It also notes that FAA AD2003-04-26 Amdt 39-13075 refers (Note), which situates the CASA AD in a contemporaneous regulatory response but does not in this text constitute an amendment to the CASA AD.

Key date markers in the AD text show procedural timing for its issuance and effect:

• CASA delegate signed the AD on 5 March 2003 (signature block).
• The AD was notified in the Commonwealth of Australia Gazette on 26 March 2003 (final line).
• The AD states it “becomes effective on 17 April 2003” (Compliance).

This sequence shows a delegate signature date, a Gazette notification date and an effective date. The AD’s Compliance section also sets calendar deadlines for action: certain inspections and the Group 2 sync-wire shield modification are required before 21 October 2003; other required modifications must be accomplished before further flight after the relevant inspection (Compliance; Requirements 1-5). Requirements 6 and 7 (the prohibitions on installation and STC incorporation) are effective as of the AD’s effective date (17 April 2003) (Compliance).

The supplied AD does not record any later revisions, supersessions, or cancellations of this AD. The absence of an amendment history in the AD text means practitioners must check CASA’s current AD database or subsequent Gazettes for any later actions amending, superseding, or rescinding AD/BEECH 1900/39. The AD’s cross-reference to the FAA AD indicates contemporaneous FAA action; any FAA amendments to their AD or related FAA service difficulty data after the dates in this AD are not recorded here.

Where a maintenance organisation or operator is preparing a continuing airworthiness status file, the AD as provided supplies a single-version baseline: effective date 17 April 2003, tasks and prohibitions enumerated in Requirements 1-7, and reliance on SB 24-3215 Rev. 1 (June 2001) and the Model 1900D AMM for technical procedures. Any later amendments to SB 24-3215, or subsequent revisions to the AMM, or later CASA ADs that reference this AD, are not contained in this document and would need to be checked externally.

The AD text supplied does not contain any litigation history, court decisions, or references to judicial review. It cites only administrative and regulatory materials: the statutory basis (subregulation 39.1(1) of CAR 1998), Raytheon Aircraft Service Bulletin SB 24-3215 Rev. 1 (June 2001), the Model 1900D Airliner Maintenance Manual (AMM), FAA Supplemental Type Certificate SA00245WI-D, and FAA AD2003-04-26 Amdt 39-13075 (Note). The Background refers to nine FAA-reported incidents of inverter shutdown leading to loss of certain electrical systems, which is the factual predicate for the AD, but no litigation or dispute resolution processes are mentioned in the AD text.

Because the AD is an administrative regulatory instrument, any legal challenges to its validity, to the delegate’s exercise of authority, or to the procedural adequacy of its issuance would arise outside the AD text. The AD does not record whether such challenges have been brought or resolved. The AD’s signatory and Gazette notification entries indicate procedural steps in its issuance (delegate signature on 5 March 2003; notified in the Gazette on 26 March 2003; effective 17 April 2003), but the AD does not detail administrative appeal rights, merits review avenues, or any litigation outcomes.

Practitioners seeking litigation history relevant to this AD must therefore consult external sources: court records, Administrative Appeals Tribunal files, CASA enforcement notices, or subsequent regulatory actions that might have been the subject of judicial review. The AD itself provides no examples of contested enforcement or judicial precedent. The only cross-reference to non-Australian regulatory action is the FAA AD noted; the AD does not state whether any FAA judicial or administrative challenges occurred.

The AD contains several practical features and potential sources of operational friction that operators and maintainers should note, all grounded in the AD’s own text.

1. Serial-number and modification identification quirks. The AD targets KGS Electronics AC Inverter P/N SPC-10(PW) with serial numbers 306 through 803. Requirement 1 then directs inspection to determine if that inverter is installed and is “identified as Mod 2DD.” The Background states that the FAA reports involved inverters “equipped with KGS Electronics AC Inverter P/N SPC-10(PW), Mod 2, serial numbers 306 to 803.” That juxtaposition means operators must be precise in distinguishing Mod 2 from Mod 2DD. The AD’s operative requirements reference Mod 2DD as the identifying mark that relieves an aeroplane from further inverter modification under Requirement 2; this potentially creates ambiguity where logbook or component markings are inconsistent with manufacturer terminology. Operators should therefore ensure that the recorded modification identifications correspond exactly to the AD’s phrasing so that “positively shown” evidence is accepted.

2. “Positively shown” evidentiary standard. The AD permits relief from further modification where Mod 2DD or absence of STC SA00245WI-D can be “positively shown” by logbook or visual inspection (Requirements 1 and 3). The AD does not define “positively shown,” which makes the sufficiency of logbook entries or visual markings a practical point of contention. Maintenance certifying staff must be able to justify that the record or visual evidence meets this threshold. In marginal cases, operators who rely on ambiguous entries risk later being required to perform the modification.

3. Different requirements by group. The AD applies different actions to each serial-number group: Group 1 has the fullest set of inspections and conditional STC checks (Requirements 1, 3, 4); Group 2 gets a mandatory sync-wire shield modification (Requirement 5) but may not require the STC inspection if not in Group 1; Group 3 is within the inspection and replacement-part prohibition regime (Requirements 1 and 6). Operators with mixed fleets or with aircraft that have been re-serialled, or that have non-standard records, must map each aeroplane to the correct group.

4. Timing traps. Deadlines vary by requirement: certain inspections and the Group 2 modification must be performed before 21 October 2003 (Compliance), while other modifications must be done “before further flight” after the inspection (Requirements 2 and 4). The prohibition on installing specified inverters and incorporation of the FAA STC is effective as of the AD’s effective date 17 April 2003 (Requirements 6 and 7; Compliance). Failure to track these different timings could leave an aircraft grounded or non-compliant.

5. Prohibition on replacement installations. Requirement 6 bars the installation of any KGS SPC-10(PW) with S/N 306-803 that is not identified as Mod 2DD as a replacement part. That restriction may complicate parts management and spares procurement for operators who hold inventory of such inverters. Sellers and purchasers must check serial numbers and mod identification before any replacement installation.

6. STC incorporation constraint. Requirement 7 prevents incorporation of FAA STC SA00245WI-D into Group 1 aeroplanes unless Requirement 4’s modification has been accomplished. For maintenance shops or modification centres offering STC work, this creates a precondition: the sync-wire shield modification must be done in advance or as part of the STC incorporation process in order for the STC to be legally incorporable on Group 1 aircraft.

7. Reliance on external documents. The AD mandates compliance with Raytheon SB 24-3215 Rev. 1 and the Model 1900D AMM. If either document is ambiguous, out of date, or if later revisions exist, the AD text does not address which revision controls beyond naming Rev. 1. Operators should ensure they use the exact revision cited by the AD for compliance.

8. Cross-jurisdictional confusion. The AD references FAA action and an FAA STC. Operators interacting with FAA-derived modifications or working on aircraft that sometimes operate out of the United States should be mindful that an FAA STC may have different regulatory implications in Australia, given the AD’s conditional ban on incorporation unless its related mod is performed (Requirements 3, 4 and 7).

9. Record-keeping exposure. Because the AD allows logbook evidence to avoid duplication of work, operators who cannot demonstrate prior Mod 2DD installation or the absence of the FAA STC may be required to perform the modification(s) even where actual risk is low. Conversely, poor records could lead to later scrutiny if an incident occurs.

10. No penalties listed in the AD text. The AD imposes prohibitions and deadlines but does not specify penalties within the AD. That omission does not mean non-compliance carries no consequence; rather, enforcement and penalties would arise under the broader statutory regime (the AD’s authority under subregulation 39.1(1) CAR 1998). Operators should not rely on the absence of penalties in the AD text.

These practical considerations should be addressed in maintenance planning, parts procurement, and record-keeping to avoid operational surprises and to demonstrate compliance under the AD’s conditional and timing provisions.

Follow these step-by-step actions derived directly from the AD text, noting the required documents and deadlines. Each step cites the AD Requirement(s) and the Compliance section.

1. Identify applicable aeroplanes. Determine whether each Model 1900D in your fleet falls into Group 1 (S/N UE-1 through UE-265), Group 2 (S/N UE-266 through UE-388) or Group 3 (S/N UE-389 through UE-410) (Applicability). Map serial numbers to groups before undertaking inspections or modifications.

2. Obtain mandated technical documents. Secure Raytheon Aircraft Service Bulletin SB 24-3215, Rev. 1, June 2001 (Accomplishment Instructions) and the Model 1900D Airliner Maintenance Manual (AMM). The AD requires work be done “in accordance with” the SB and the AMM (Requirements 1-5).

3. Perform Requirement 1 inspection on all Groups 1-3. For each aeroplane, inspect the AC inverter to determine if KGS Electronics AC Inverter P/N SPC-10(PW), with a serial number in the range 306 through 803, is installed and whether it is identified as Mod 2DD. Use the SB’s Accomplishment Instructions for the inspection procedure (Requirement 1). Deadline: complete this inspection before 21 October 2003 (Compliance).

4. Record and evaluate evidence for Mod 2DD. If you can “positively show” by checking the aeroplane logbook or by visual inspection that a Mod 2DD inverter is installed, Requirement 2 does not apply for that aeroplane (Requirement 1). Ensure that logbook entries or physical markings are sufficiently clear and documented, as the AD expressly allows reliance on those materials.

5. If Mod 2DD is not present, accomplish the inverter modification per the SB and AMM. Where the inspection reveals that a KGS SPC-10(PW) with S/N 306-803 is installed but is not identified as Mod 2DD, perform the AC inverter modification according to the Accomplishment Instructions of SB 24-3215 Rev. 1 and the Model 1900D AMM. This modification must be accomplished before further flight after the Requirement 1 inspection (Requirement 2).

6. For Group 1, perform Requirement 3 STC inspection. Inspect the AC inverter (per the SB) to determine if FAA STC SA00245WI-D has been installed (Requirement 3). Deadline: before 21 October 2003 (Compliance). If logbook or visual inspection can “positively show” that the FAA STC has never been installed, Requirement 4 will not apply.

7. If FAA STC is present on a Group 1 aeroplane, perform Requirement 4 sync wire shield modification. If Requirement 3 inspection establishes the STC is installed, accomplish the AC inverter synchronisation (sync) wire shield modification per the SB and the Model 1900D AMM before further flight after the Requirement 3 inspection (Requirement 4).

8. For Group 2, perform sync wire shield modification per Requirement 5. Accomplish the AC inverter sync wire shield modification per SB 24-3215 Rev. 1 and the AMM. Deadline: before 21 October 2003 (Requirement 5; Compliance).

9. Observe installation prohibitions effective 17 April 2003. Do not install, as a replacement part, any KGS Electronics AC inverter P/N SPC-10(PW) with S/N between 306 through 803 that is not identified as having Mod 2DD incorporated (Requirement 6). Also do not incorporate FAA STC SA00245WI-D on any Group 1 aeroplane unless the Requirement 4 AC inverter modification has been accomplished (Requirement 7). These prohibitions are effective as of the AD’s effective date, 17 April 2003 (Compliance).

10. Certify and document compliance. After completing inspections and any required modifications, ensure maintenance records in the aeroplane logbook are updated to demonstrate compliance with the AD, including reference to SB 24-3215 Rev. 1 and the AMM procedures used, dates of work carried out, and signatures of certifying maintenance personnel. Where Mod 2DD or absence of STC was relied upon to avoid modification, document the logbook and visual evidence relied upon.

11. Plan for parts and STC transactions. When sourcing replacement inverters, verify part number, serial numbers and Mod 2DD identification before installation to avoid installing a prohibited unit. If considering incorporation of FAA STC SA00245WI-D into a Group 1 aeroplane, ensure the sync wire shield modification required by Requirement 4 is in place.

12. Monitor regulatory updates. The AD cites FAA AD2003-04-26 and requires the use of SB 24-3215 Rev. 1. Practitioners should monitor CASA publications and manufacturer service bulletins for any revisions, supersessions or additional guidance that might affect the methods of compliance or compliance timings.

13. Operational sequencing. For any aircraft found to have disqualifying inverters or STC installations, schedule modifications to be done “before further flight” when discovered. For aircraft that pass the inspection by virtue of recorded Mod 2DD or absence of STC, retain and clearly index the evidence to avoid rework.

Following these steps, using the exact service bulletin revision and AMM sections cited in the AD, and respecting the calendar and “before further flight” deadlines, will meet the AD’s prescriptive requirements as stated in the document.