{"id":"F2005L03544","name":"AD/B727/198 - Lower Lobe Frames of Body Section 43","slug":"ad-b727-198-lower-lobe-frames-of-body-section-43","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":39052,"registerId":"commonwealth-F2005L03544-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"Boeing 727 Series Aeroplanes","sectionType":"division","heading":"Boeing 727 Series Aeroplanes","content":"### Boeing 727 Series Aeroplanes\n\n| AD/B727/198 | Lower Lobe Frames of Body Section 43 | 13/2005 |\n| ----------- | ------------------------------------ | ------- |\n\n| Applicability: | All Model 727, 727C, 727-100, 727-100C, 727-200, and 727-200F series aircraft.                                                                                                                                                                                                                                  |\n| -------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement:   | Action in accordance with the technical requirements of FAA AD 2005-20-13Amdt 39-14307.Note: Boeing Alert Service Bulletin 727-53A0227 original issue, or later FAA revision, refers.                                                                                                                           |\n| Compliance:    | As specified in the Requirement document, with a revised effective date of22 December 2005.                                                                                                                                                                                                                     |\n|                | This Airworthiness Directive becomes effective on 22 December 2005.                                                                                                                                                                                                                                             |\n| Background:    | The FAA received the results from reports of cracks at open tooling holes in the lower lobe frames of body section 43. The actions required by this Directive are intended to detect and correct cracks in the frames, which could result in cracks in the skin panels and rapid decompression of the aircraft. |\n\n![](image.001.png)  \nDavid Villiers  \nDelegate of the Civil Aviation Safety Authority\n\n8 November 2005","sortOrder":0},{"sectionNumber":"AD/B727/198","sectionType":"part","heading":"AD/B727/198","content":"## AD/B727/198","sortOrder":1},{"sectionNumber":"Lower Lobe Frames of Body Section 43","sectionType":"part","heading":"Lower Lobe Frames of Body Section 43","content":"## Lower Lobe Frames of Body Section 43","sortOrder":2},{"sectionNumber":"13/2005","sectionType":"part","heading":"13/2005","content":"## 13/2005","sortOrder":3}],"analysis":{"flash_summary_failed":{"failed":true,"reason":"Unauthenticated. Configure AI_GATEWAY_API_KEY or use a provider module. Learn more: https://ai-sdk.dev/unauthenticated-ai-gateway","source":"analysis-cron"},"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":false,"description":"This instrument does not change the scope beyond its original safety-focused purpose. It requires operators of the listed Boeing 727 variants to follow the inspection and corrective actions in the referenced FAA AD and Boeing Service Bulletin to detect and fix cracks in lower lobe frames of body section 43. The only substantive administrative modification shown is a revised effective date (22 December 2005). The instrument’s scope remains limited to identifying and correcting the specific structural cracking risk described in the Background; it does not add other subjects or broaden applicability beyond the listed aircraft types. (Applicability / Requirement / Compliance)"},"complexity_factors":["Short instrument text but relies on external technical documents (FAA AD 2005-20-13 and Boeing Alert Service Bulletin 727-53A0227) for operative detail","Cross-referencing to later FAA-approved revisions (allows future technical changes without reissuing the Australian instrument)","Applicability spans multiple closely related models (six model groups), requiring fleet-level checks","Compliance timing is set by an effective date but specific inspection intervals and repair procedures are not reproduced in the instrument (requires reading referenced documents)","Potentially significant operational complexity (maintenance scheduling, parts supply, and engineering approvals) despite simple statutory wording","Limited number of conditional clauses in this instrument itself (simplicity of drafting) but practical complexity arises from technical content in the referenced material","Enforcement/oversight complexity: CASA enforces compliance but relies on FAA/Boeing technical content, creating multijurisdictional dependency"],"plain_english_summary":"**What this instrument does (mechanically)\n\n- Requires owners/operators of specified Boeing 727 series aeroplanes to carry out the inspection and corrective actions set out in a referenced FAA Airworthiness Directive (FAA AD 2005-20-13, amendment 39-14307) and the Boeing Alert Service Bulletin 727-53A0227 (original issue, or any later FAA-approved revision). (Requirement)\n- Applies to all Model 727, 727C, 727-100, 727-100C, 727-200 and 727-200F aircraft operated in Australia. (Applicability)\n- Sets the effective compliance start date as 22 December 2005; operators must comply from that date. (Compliance)\n\n\nWhy the rule exists (stated reason)\n\n- The FAA reported crack findings at open tooling holes in the lower lobe frames of body section 43. The stated purpose of the required inspections and repairs is to detect and correct those cracks before they propagate into skin panels and create a risk of rapid decompression. (Background)\n\n\nWho this affects and who decides\n\n- Who pays: aircraft operators and their maintenance providers pay for the inspections, repairs, parts and downtime required to meet the AD. (Requirement / Applicability)\n- Who decides operationally: the Civil Aviation Safety Authority (CASA) enforces the directive in Australia by mandating compliance with the FAA AD and Boeing Service Bulletin. The technical content and specific procedures are contained in the FAA AD and Boeing Service Bulletin that the instrument references. (Requirement / Compliance)\n\n\nWhat behaviour changes for affected parties\n\n- Operators must schedule and conduct the specified inspections on the lower lobe frames of body section 43 and carry out any corrective repairs or reinforcement as required by the referenced FAA AD and Boeing Service Bulletin.\n- Maintenance organisations (approved maintenance organisations / AMOs) will perform the work, record compliance in maintenance logs, and may need to source parts or structural repairs. Aircraft may be withdrawn from service for inspection/repair, affecting flight schedules.\n\n\nPractical implications, trade-offs and implementation risks\n\n- Direct costs and business effects: operators bear the labour, parts, and facilities costs and the opportunity cost of aircraft downtime. The directive will raise short-term maintenance expenditure and may reduce available flight capacity while work is done. (Requirement / Compliance)\n- Supply and service effects: demand for specific parts, engineering support and repair services will rise; Boeing and certified MROs may supply the work and parts. Independent MROs can perform the work if they have access to the Boeing procedures and required parts/data. (Requirement)\n- Enforcement and updating: CASA enforces compliance but the technical requirements are set by the FAA AD and the Boeing Service Bulletin; those documents may be revised by FAA/Boeing, and the AD allows compliance with later FAA-approved revisions. This cross‑referencing means operators must track the FAA/Boeing documents for any updates. (Requirement)\n- Safety benefit vs cost: the intended safety benefit is prevention of structural crack growth that could lead to skin failure and rapid decompression. The trade-off is increased maintenance cost and aircraft downtime; the directive substitutes a preventive inspection/repair cost for the higher but uncertain cost and risk of an in-service structural failure. (Background / Requirement)\n- Implementation risks: if parts or approved repair methods are scarce, operators may face extended groundings. Variability in interpreting or applying the referenced FAA/Boeing instructions could cause inconsistent repairs across operators unless overseen by CASA. (Requirement / Compliance)\n\n\nOther practical notes\n\n- The instrument is short and functions mainly by mandating compliance with the referenced FAA AD and Boeing Service Bulletin; it does not repeat the technical inspection intervals or repair techniques in full — operators must consult those external documents for detailed instructions. (Requirement)\n- The effective date referenced here supersedes any earlier date mentioned elsewhere; operators must ensure compliance from 22 December 2005. (Compliance)\n\n\nSource attribution\n\n- The Directive cites FAA crack reports as the factual basis for prescribing inspections and cites Boeing Alert Service Bulletin 727-53A0227 as the procedural source; those are the documents operators must follow in practice. (Background / Requirement)\n"},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a standard, narrow Airworthiness Directive addressing a specific structural defect in a specific aircraft type. It has not expanded beyond its original safety purpose."},"complexity_factors":["Very short document (approximately 200 words of substantive content)","Only 1 defined term implicitly referenced (the FAA AD number)","No conditional logic or nested exceptions — simple mandatory requirement","Single cross-reference to external technical document (FAA AD 2005-20-13 and Boeing Service Bulletin)","Clear, unambiguous compliance date (22 December 2005)","No interpretation section or extensive definitions"],"plain_english_summary":"This mandatory AD orders operators of all Boeing 727 series aircraft in Australia to inspect and repair lower-lobe fuselage frames where cracks have been found starting at open tooling holes. Left unaddressed, these cracks can spread into skin panels and risk rapid decompression. Compliance follows the FAA’s AD 2005-20-13 and the referenced Boeing service bulletin; it’s a critical fatigue-safety measure for ageing 727 fleets."}},"importantCases":[],"_links":{"self":"/api/acts/ad-b727-198-lower-lobe-frames-of-body-section-43","history":"/api/acts/ad-b727-198-lower-lobe-frames-of-body-section-43/history","analysis":"/api/acts/ad-b727-198-lower-lobe-frames-of-body-section-43/analysis","conflicts":"/api/acts/ad-b727-198-lower-lobe-frames-of-body-section-43/conflicts","importantCases":"/api/acts/ad-b727-198-lower-lobe-frames-of-body-section-43/important-cases","documents":"/api/acts/ad-b727-198-lower-lobe-frames-of-body-section-43/documents"}}