AD/B717/29 - Airworthiness Limitations - Fuel System Safety

The AD operates through three core concepts: (1) mandatory revision of the Airworthiness Limitations section of the ICA, (2) standard-setting by reference to a specific manufacturer report (Report MDC-92K9145, Revision G), and (3) constrained alternatives subject to FAA managerial approval. Each concept is stated in the AD text and determines who controls acceptable inspection regimes and CDCCLs after the revision is made.

Mandatory AWL revision. The AD requires operators to "revise the Airworthiness Limitations (AWL) section of the Instructions for Continued Airworthiness (ICA) to incorporate the information specified in Appendixes B, C, and D of Report MDC-92K9145." The requirement is an operational instruction to change the ICA content maintained by the operator or the approved maintenance organisation. The AD does not articulate technical content beyond naming the appendices, so the specific inspection tasks, intervals and limitations are those contained in the referenced appendices.

Standard-setting by reference. The AD identifies a specific document as the normative source: "Report MDC-92K9145, Revision G, dated 7 June 2007." The AD treats the appendices of that report as the airworthiness-limitation standard to be inserted into each operator's ICA. The AD also permits reliance on a later revision of the same report, but only if that later revision is approved by a named FAA official. Therefore, the AD uses a join between CASA regulatory authority and FAA certification oversight, by adopting an FAA-originated compliance document as authoritative for the AWLs.

Constraints on alternatives. The AD places a constraint on variations after the AWL revision is completed. It provides that "no alternative inspections, inspection intervals, or Critical Design Configuration Control Limitations (CDCCL) may be used unless" either the variation appears in an FAA-approved later revision of the same report, or the variation is approved as an AMOC to FAA AD 2008-11-15 by the Manager, Los Angeles ACO. That language has three mechanical effects: it freezes local, operator-devised variations following incorporation of the specified AWLs; it assigns final approval discretion to the Manager, Los Angeles ACO; and it links any conditional approval path to the FAA AD identified in the Note.

Cross-reference and international regulatory interplay. The AD expressly references FAA AD 2008-11-15 Amdt 39-15538, and the Manager, Los Angeles ACO of the FAA is the named approving authority for later revisions or AMOCs. Therefore the AD depends on transnational regulatory coordination to permit alternative compliance paths, rather than leaving variation approval entirely to CASA or to an Australian authority.

Temporal limits. Two time points are provided: an effective date (31 July 2008) and a compliance deadline (before 16 December 2008). The AD therefore sets a compliance window of just under five months in which operators must incorporate the specified AWL changes into their ICAs.

Scope. The AD applies to "All Model 717-200 aeroplanes." No other models are included in the text. The AD does not enumerate serial numbers or other sub-sets; it is blanket in its applicability to that model designation.

Background rationale. The AD's single-paragraph background explains the safety concern as arising from "a design review of the fuel tank systems" and aims to "prevent the potential for ignition sources inside fuel tanks caused by latent failures, alterations, repairs or maintenance actions" which could, the AD claims, create conditions for a fuel tank explosion. That is the only stated hazard and the only justification within the text.

The directive explicitly affects operators and the continuing airworthiness system for "All Model 717-200 aeroplanes." That includes any entity responsible for the Instructions for Continued Airworthiness for those aeroplanes, typically the registered aircraft owners, their nominated maintenance organisations and the persons or organisations who hold the ICA documentation for the aircraft. The AD requires changes to the AWL section of the ICA, which is a document maintained by the operator or their approved maintenance organisation, so responsibility for revision and implementation sits with those parties.

Maintenance organisations and licensed maintenance personnel will be operationally affected because the AWL changes will, by definition, alter or add mandatory inspections, intervals or CDCCLs that maintenance staff must carry out and record. The AD does not itself assign tasks between operator and maintenance organisation, but by changing the ICA it changes the mandatory maintenance envelope to which maintenance providers must adhere.

Regulators are affected in a supervisory and approval sense. The AD names the Manager, Los Angeles Aircraft Certification Office of the FAA as the approving authority for later revisions of the report and for AMOCs to FAA AD 2008-11-15. This assigns a specific FAA official central authority to approve alternatives. CASA, as the issuing authority for this AD, retains issuance power but has linked some decisions to an FAA manager, so both CASA and the FAA are implicated in oversight and approvals.

Suppliers and manufacturers may be indirectly affected. The requirement references the Boeing report (Report MDC-92K9145 Revision G) which is a manufacturer-originated compliance document. Operators will need access to that report and its appendices, so manufacturers and document custodians are implicated in distribution and potential technical support.

Safety management and compliance personnel are affected because they must ensure ICA amendments are made in time, that maintenance programmes reflect the new AWLs, and that any requests for alternative compliance follow the approval channels named in the AD. The AD gives no explicit forms or approval templates, but it does identify the Manager, Los Angeles ACO and FAA AD 2008-11-15 as the procedural anchors for any alternatives.

No individual crew procedures, operational flight rules, or airworthiness limitations outside those appendices are changed by the AD text. The AD does not mention pilot operating procedures, operational limitations, or airworthiness certificates. It is confined to the AWL content of the ICA for Model 717-200 aeroplanes.

The AD imposes a single express duty and specifies constrained rights for alternatives. Duty: revise the AWL section of the ICA to incorporate Appendices B, C and D of Report MDC-92K9145. That duty is unqualified in the text as the primary mandatory action. The AD instructs operators to make this revision and sets a compliance deadline "before 16 December 2008" and an effective date "31 July 2008." The text requires incorporation of the specific appendices; it does not give operators the option to adopt only parts of those appendices.

Post-revision restrictions. After the mandated AWL revision is accomplished, the AD prohibits the use of "alternative inspections, inspection intervals, or Critical Design Configuration Control Limitations (CDCCL)" unless those alternatives are either (a) part of a later revision of Report MDC-92K9145 that is approved by the Manager, Los Angeles ACO; or (b) approved as an AMOC to FAA AD 2008-11-15 by the Manager, Los Angeles ACO. The AD therefore prescribes that operators lose the unilateral right to choose different inspections or intervals once the required AWL text is adopted.

Conditional rights via FAA approvals. The AD grants conditional rights to use different inspection regimes or CDCCLs, but those rights are exercisable only with the Manager, Los Angeles ACO's approval. The AD states that "accomplishing the revision in accordance with a later revision of Report MDC-92K9145 is an acceptable method of compliance if the revision is approved by the Manager, Los Angeles ACO." This ties acceptability to FAA approval of a later revision. Likewise, AMOC approval for alternatives must be obtained from the same Manager as a path to deviate from the incorporated AWLs. The AD does not provide a domestic CASA approval pathway for alternatives; it instead points to the FAA manager as the approval authority.

Documentation duty. The duty to revise the AWL section of the ICA is a documentation duty: the operator must make the change to the ICA. The AD does not state an express requirement for CASA approval of that ICA revision, nor does it say the ICA revision must be submitted to CASA. The AD does not state a requirement to notify any authority upon completion, but the compliance date and effective date are explicit. The operator's compliance record-keeping obligations implicit in continuing airworthiness practice are not spelled out in the text of this AD.

No explicit right to phase-in. The AD sets a single compliance deadline and does not provide staged implementation options or temporary relief in the text. The only conditional exception mechanism is the AMOC process administered by the Manager, Los Angeles ACO in the FAA.

Technical content duty allocation. The AD references Appendices B, C and D of the stated report as the technical content to be adopted into the AWLs. The AD does not itself translate those technical tasks into a schedule or assign discrete tasks to specific roles. That allocation will be realised in each operator's ICA and maintenance arrangements after the revision.

Summary. Key duties are the incorporation of the specified AWLs into each ICA and adherence to the revised inspections, intervals and CDCCLs. Key constrained rights are the ability to use alternative inspections, intervals or CDCCLs only with the FAA Manager's approval either through an approved later revision or an AMOC to FAA AD 2008-11-15.

The AD text sets legal temporal obligations and specifies compliance actions but does not itself include enforcement procedures or penalty provisions. The document states that it "becomes effective on 31 July 2008" and that compliance is required "before 16 December 2008." It also prescribes the required technical amendment: to "revise the Airworthiness Limitations (AWL) section of the Instructions for Continued Airworthiness (ICA) to incorporate the information specified in Appendixes B, C, and D of Report MDC-92K9145." The AD contains no express penalty clauses, fines, or infringement mechanisms in its text.

Because the AD is issued by the Civil Aviation Safety Authority (CASA), and is titled as an Airworthiness Directive, it is a mandatory regulatory instrument in its regulatory context. The AD itself, as provided, does not enumerate procedures for CASA enforcement action, corrective direction, grounding of aircraft, or the imposition of fines. The AD does refer to FAA processes for approval of later revisions and AMOCs, but it does not describe enforcement mechanisms associated with those approvals.

The lack of penalties in the text means that the AD establishes the operational duty and the timeframes; it does not set out, within its own text, the consequences of non-compliance. Parties reading this AD should note the normative requirement and the compliance dates; any practical enforcement or penalty regime would be set out in broader aviation legislation and CASA regulatory procedures, which are not contained in the AD text itself.

The AD also identifies the Manager, Los Angeles ACO as the approving authority for later revisions and AMOCs. The AD does not specify what action follows if an operator fails to obtain such approvals but continues to use alternative inspections. The AD simply prohibits such alternatives unless the specified approval paths are used.

In short, the AD specifies the mandatory revision, the timeframe, and the approval authority for alternatives, but it does not include any express penalty or enforcement process in its body. Readers must treat the AD's compliance requirements as binding operational instructions whose enforcement mechanisms are outside the AD's text.

This AD explicitly links its compliance regime to an FAA airworthiness directive and to FAA approval processes. It references "FAA AD 2008-11-15 Amdt 39-15538" and repeatedly identifies the Manager, Los Angeles Aircraft Certification Office (ACO) of the United States Federal Aviation Administration (FAA) as the approval authority for later revisions of Report MDC-92K9145 and for AMOCs to FAA AD 2008-11-15. Therefore the AD does not operate in isolation; it coordinates an Australian CASA directive with specific FAA certification and AMOC processes.

By making the acceptance of later revisions and AMOCs conditional on Manager Los Angeles ACO approval, the AD creates an inter-agency dependency. Operators who seek to vary the mandated AWLs must use the FAA approval channels named in the AD. The AD does not provide an alternative Australian domestic approval path for such variations in its text, and it does not state whether CASA itself will accept or deny variations absent FAA approval. It also does not state whether CASA will accept direct submissions to CASA for AMOCs or later revisions. The text therefore situates the FAA Manager as a gatekeeper for permitted deviations from the mandate, at least insofar as the AD's text is concerned.

The AD incorporates by reference the manufacturer's report (Report MDC-92K9145, Revision G, dated 7 June 2007). This is a form of regulatory incorporation by reference: the AD makes specified manufacturer's content normative by requiring its incorporation into operator ICAs. The AD itself does not reproduce the technical content of Appendices B, C and D, so the technical specifics become enforceable only through incorporation into operator ICAs.

The AD does not mention other Australian legislative instruments, civil aviation regulations, or matters such as design organisation approval, continuing airworthiness management approvals, or air operator certification. It also does not reference any state-level transport legislation. The AD is therefore narrowly framed, and any broader interaction with the Australian regulatory framework (for example, how CASA might enforce, approve alternatives, or record ICA revisions) is not addressed in the text.

Finally, the AD's cross-reference to FAA AD 2008-11-15 indicates that operators should be mindful of the FAA AD's content and AMOC process. The AD does not provide details about that FAA AD beyond the reference, so the compliance environment for an Australian operator who wishes to pursue an AMOC or rely on a later revision requires engagement with the FAA approval process cited.

The AD text provided identifies the following chronology and documentary links. The AD itself is dated 13 June 2008 and signed by James Coyne, Delegate of the Civil Aviation Safety Authority. It is captioned 8/2008 with the identifier AD/B717/29. The AD states the relevant Boeing compliance document as "Report MDC-92K9145, Revision G, dated 7 June 2007." The AD also contains two notes: Note 1 defines the term "Report MDC-92K9145" to mean the Boeing Twinjet Special Compliance Items Report, MDC-92K9145, Revision G, dated 7 June 2007. Note 2 records that "FAA AD 2008-11-15 Amdt 39-15538 refers."

The AD sets two formal dates in its operative text. It states that it "becomes effective on 31 July 2008" and that compliance is required "before 16 December 2008." There is no schedule of later amendments or subsequent ADs within the document. The AD permits a method of compliance that relies on a later revision of the referenced report, but only if that later revision is approved by the Manager, Los Angeles ACO of the FAA. That approval mechanism signals that amendments to the technical requirements could occur through the revision process overseen by the FAA manager, but the AD itself contains no record of subsequent amendments.

The AD also references FAA AD 2008-11-15; the AD therefore acts as an implementing instrument that ties Australian operator obligations to a specific revision of a Boeing report and to an FAA AD. The AD does not list any prior versions of AD/B717/29, nor does it reference prior CASA ADs concerning Model 717-200 aeroplanes. It also does not record any CASA amendments or revocations beyond the dates and references already mentioned.

Given the AD's instruction that "Accomplishing the revision in accordance with a later revision of Report MDC-92K9145 is an acceptable method of compliance if the revision is approved by the Manager, Los Angeles ACO," the amendment history relevant to operators would be the sequence of revisions to Report MDC-92K9145 approved by the FAA manager. Those later revisions, if approved, would be acceptable for compliance in place of Revision G. The AD does not list any such later revisions; it only sets the mechanism by which later revisions become acceptable.

No other amendment notes, revocation clauses, or sunset provisions appear in the AD text provided.

The AD text supplied does not include or reference any litigation history. It does not cite decisions, court challenges, administrative appeals, or dispute resolution processes relating to this directive. The document is purely a regulatory instrument and its text contains no record of judicial or administrative challenges.

Because the AD references an FAA AMOC process and FAA AD 2008-11-15, any litigation that might have arisen over those FAA instruments is not recorded in this AD. The AD itself contains no notes that any part of its requirement has been stayed, suspended, appealed, or otherwise contested.

Therefore, based solely on the AD text, there is no litigation history to report. The AD's compliance and approval mechanisms are administrative and point to the Manager, Los Angeles ACO for approvals of later revisions or AMOCs; the AD does not specify any review or appeal path within its own text.

Readers who require information on whether any legal challenges were brought against the FAA AD referenced, or whether CASA took further administrative action after this AD, will need to consult sources beyond this AD, because no such matters are recorded here.

This AD contains several operational pitfalls that arise from its specific wording and the approval channels it designates. The following list sets out concrete points that operators and maintainers should be aware of when implementing the directive.

1. Single-source normative material. The AD requires incorporation of "Appendixes B, C, and D of Report MDC-92K9145." The AD does not reproduce those appendices, so operators must obtain the specified revision of the report (Revision G dated 7 June 2007) to know the exact tasks, intervals and CDCCLs they are required to adopt. Failing to acquire the correct revision risks non-compliance with the AD.

2. No partial adoption permitted. The AD requires the AWL section to be revised "to incorporate the information specified in Appendixes B, C, and D." The AD language does not provide an option to adopt only selected items from those appendices. Operators should not attempt to cherry-pick tasks or intervals from the appendices without securing approval under the AMOC or later revision process.

3. Post-adoption freeze on alternatives. The AD explicitly states that after the AWL revision is accomplished no alternative inspections, inspection intervals, or CDCCLs may be used unless they are part of a later revision approved by the Manager, Los Angeles ACO, or are approved as an AMOC to FAA AD 2008-11-15 by that Manager. This means that once operators have incorporated the mandated AWLs, any desire to deviate will require FAA managerial approval. Operators should not assume local CASA approval mechanisms permit deviation.

4. Reliance on FAA managerial approval. The AD names the Manager, Los Angeles ACO of the FAA as the approval authority for later revisions and AMOCs. Obtaining those approvals may require engagement with FAA processes that are external to domestic CASA procedures. Operators should not overlook lead times and documentation requirements that the FAA manager may require.

5. Dates are binding and not soft. The AD becomes effective on 31 July 2008 and requires compliance "before 16 December 2008." There is no grace period described in the AD text. Operators must plan to have the ICA AWL revised and the changes implemented within that window.

6. Cross-reference to FAA AD 2008-11-15. The AD makes AMC (Alternative Method of Compliance) approval dependent on the AMOC process to FAA AD 2008-11-15. An operator seeking an alternative must review that FAA AD and its AMOC procedures to ensure conformity. The AD does not summarise the FAA AD's content, and operators should not assume their alternatives will be considered without meeting AMOC procedural requirements.

7. No enforcement mechanics in-text. The AD does not set out how CASA will enforce compliance or what records to submit upon completion. Operators should not treat the absence of enforcement language as a permission to delay compliance.

8. Who updates the ICA. The AD requires revision of the AWL section of the ICA, but does not specify whether that ICA revision must be processed through a nominated continuing airworthiness management organisation or whether it requires further CASA acceptance. Operators must ensure that the ICA revision becomes the operative maintenance control document for the aircraft.

9. No grandfathering of prior practices. The AD indicates that after the AWL revision is made "no alternative inspections, inspection intervals, or CDCCL may be used", which suggests that practices operators were using that do not match the incorporated appendices may become non-compliant unless approved. Operators relying on bespoke inspection regimes should verify compatibility before the compliance date.

10. Document identification snag. The AD defines "Report MDC-92K9145" by reference to Revision G dated 7 June 2007. Operators must ensure they reference the correct revision date and edition. Using an earlier or later revision without approval may not satisfy the AD.

Operators should treat these "gotchas" as concrete procedural risks arising from the AD's exact language and approval channels.

The AD prescribes a concise compliance path. Follow these steps, grounded in the directive's requirements and approval references.

1. Confirm applicability. Verify that the aircraft in scope are indeed "All Model 717-200 aeroplanes." If your fleet includes Model 717-200 aeroplanes, the AD applies and the tasks below are mandatory.

2. Obtain the identified report revision. Acquire Report MDC-92K9145, Revision G, dated 7 June 2007 (the Boeing Twinjet Special Compliance Items Report). The AD defines "Report MDC-92K9145" as that specific revision in Note 1. Operators must possess the appendices to know the precise tasks, intervals and CDCCLs that must be incorporated.

3. Revise the AWL section of the ICA. Update the Airworthiness Limitations (AWL) section of the Instructions for Continued Airworthiness (ICA) to incorporate the information specified in Appendices B, C and D of Report MDC-92K9145, Revision G. The AD makes this incorporation the primary required action.

4. Ensure timing. Complete the AWL revision and any associated procedural or maintenance programme changes before 16 December 2008. The AD becomes effective 31 July 2008; the compliance deadline is before 16 December 2008. Schedule resources, technical publication updates and maintenance slots accordingly.

5. Do not use alternative inspections or CDCCLs after revision unless approved. After the AWL revision is in place, do not implement alternative inspections, inspection intervals or CDCCLs unless they are either a part of a later revision of Report MDC-92K9145 that has been approved by the Manager, Los Angeles ACO, or the alternative has been approved as an AMOC to FAA AD 2008-11-15 by the Manager, Los Angeles ACO. That means any proposed deviation must be channelled to the FAA manager named in the AD.

6. If you intend to rely on a later revision of the report. If the operator prefers to adopt a later revision of Report MDC-92K9145 rather than Revision G, obtain the later revision and secure approval from the Manager, Los Angeles ACO of the FAA. The AD states that accomplishing the AWL revision in accordance with a later revision is an acceptable method of compliance only if that later revision is approved by that Manager.

7. If you intend to seek an AMOC. Any alternative method of compliance that would change inspections, intervals or CDCCLs must be submitted as an AMOC to FAA AD 2008-11-15, and must be approved by the Manager, Los Angeles ACO of the FAA. Familiarise yourself with the AMOC submission requirements in FAA AD 2008-11-15 for content, evidence and substantiation.

8. Update internal maintenance documentation and training. Once the AWL revision is incorporated into the ICA, ensure maintenance programmes, task cards, maintenance control manuals and personnel training are updated to reflect the new AWLs. The AD itself does not spell out the necessary internal record changes, but incorporation into the ICA will have practical effects on maintenance schedules and tasking.

9. Recordkeeping. Although the AD text does not prescribe a specific notification or submission obligation to CASA upon completion, maintain auditable records showing the date of the ICA AWL revision, the source document (Report MDC-92K9145 Rev G or later approved revision), and evidence that maintenance processes were updated. These records will be the primary evidence of compliance if required by regulators.

10. Engage early with approval authorities for alternatives. If you anticipate needing an alternative inspection regime or CDCCL, contact the Manager, Los Angeles ACO early and prepare supporting data. The AD makes approval dependent on that Manager where alternatives are to be used.

11. Use FAA AD 2008-11-15 as a reference. Because AMOCs are to be approved as AMOCs to FAA AD 2008-11-15, ensure your technical case and submission align with the requirements and expectations in that FAA AD. The AD does not summarise that FAA AD, so obtain and review it when preparing any AMOC.

12. Verify the exact wording. The AD requires incorporation "to incorporate the information specified in Appendixes B, C, and D of Report MDC-92K9145." Make sure that the AWL revision mirrors the appendices' requirements and does not omit required items.

These steps reflect the AD's operative obligations and the approval channels it designates. The AD leaves the detailed technical content to the incorporated appendices and to any later revisions approved by the Manager, Los Angeles ACO of the FAA.