{"id":"F2009L03645","name":"AD/B747/163 Amdt 4 - Fuselage Internal Structure","slug":"ad-b747-163-amdt-4-fuselage-internal-structure","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":141479,"registerId":"commonwealth-F2009L03645-current","compilationNumber":null,"startDate":"2026-04-03","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"Boeing 747 Series Aeroplanes","sectionType":"division","heading":"Boeing 747 Series Aeroplanes","content":"### Boeing 747 Series Aeroplanes\n\n| AD/B747/163 Amdt 4 | Fuselage Internal Structure | 11/2009 |\n| ------------------ | --------------------------- | ------- |\n\n| Applicability: | Model 747-100, -100B, -100B SUD, -200B, -300, 747SP, and 747SR series aircraft, identified in Boeing Alert Service Bulletin 747-53A2349 Revision 3, dated2 October 2008, or later FAA approved revision.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       |\n| -------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement:   | Acton in accordance with the technical requirements of FAA AD 2009-18-07Amdt 39-16003.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         |\n| Compliance:    | As specified in the Requirement document, with a revised effective date of22 October 2009.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     |\n|                | This Amendment becomes effective on 22 October 2009.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           |\n| Background:    | The manufacturer conducted pressure fatigue tests that identified areas of the fuselage internal structure where fatigue cracking occurred. Such cracking, if not detected and repaired, could result in loss of structural integrity of the fuselage and rapid depressurisation of the aircraft.Amendment 1 corrected compliance, and added an inspection area in accordance with Boeing Service Letter 747-SL-53-074.Amendment 2 added new repetitive inspections for cracking of certain areas of the upper chord of the upper deck floor beams and, if necessary, repair.Amendment 3 required repetitive inspections of additional areas of the fuselage internal structure, and related actions if necessary. The new FAA AD resulted from fatigue testing of the fuselage structure of a Model 747SR series aircraft.Amendment 4 is issued in response to a new FAA AD, which results from fatigue tests and analysis by Boeing that identified areas of the fuselage where cracks can occur; and requires additional repetitive inspections for cracking of certain fuselage structure. |\n\n![](image.001.png)  \nDavid Villiers  \nDelegate of the Civil Aviation Safety Authority\n\n4 September 2009","sortOrder":0},{"sectionNumber":"AD/B747/163 Amdt 4","sectionType":"part","heading":"AD/B747/163 Amdt 4","content":"## AD/B747/163 Amdt 4","sortOrder":1},{"sectionNumber":"Fuselage Internal Structure","sectionType":"part","heading":"Fuselage Internal Structure","content":"## Fuselage Internal Structure","sortOrder":2},{"sectionNumber":"11/2009","sectionType":"part","heading":"11/2009","content":"## 11/2009","sortOrder":3}],"analysis":{"flash_summary_failed":{"failed":true,"reason":"A positive credit balance is required for all requests, including BYOK, so fallback providers remain available. Add credits at https://vercel.com/d?to=%2F%5Bteam%5D%2F%7E%2Fai%3Fmodal%3Dtop-up to continue.","source":"analysis-cron"},"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This Airworthiness Directive maintains its original scope: ensuring structural integrity of Boeing 747 fuselages through mandatory inspections. While Amendment 4 expands the inspection requirements to cover additional areas identified in new fatigue testing, this represents a natural evolution within the original safety purpose rather than scope creep. The document remains tightly focused on fuselage internal structure inspections for the specified aircraft models."},"complexity_factors":["Short, single-purpose document (approximately 300 words)","Only 2 substantive requirements: (1) comply with FAA AD 2009-18-07, and (2) meet the specified compliance date","No defined terms section — relies on external Boeing and FAA documents for technical specifications","Simple amendment history narrative in Background section (4 sequential amendments clearly described)","Single cross-reference to external technical document (FAA AD 2009-18-07)","No conditional logic or nested exceptions — straightforward mandatory compliance structure","Clear applicability table identifying specific aircraft models by reference to Boeing service bulletin"],"plain_english_summary":"This CASA Airworthiness Directive mandates repetitive internal fuselage inspections and required repairs on specified Boeing 747 series to detect and correct fatigue cracking that could cause loss of structural integrity or rapid depressurisation. It updates prior ADs with new inspection requirements based on Boeing’s fatigue testing, applies to affected 747 variants covered by Boeing Alert Service Bulletin 747-53A2349 Revision 3 (or later FAA-approved versions), and implements FAA AD 2009-18-07."},"flash_summary":{"complexity_score":6,"scope_assessment":{"changed":true,"description":"Amendment 4 expands the inspection scope compared with earlier versions by adding additional repetitive inspections for identified fuselage areas following Boeing fatigue tests and the new FAA AD. It therefore increases required inspection coverage and associated repair actions for the models listed in the Boeing Alert Service Bulletin (Background; Requirement; Applicability)."},"complexity_factors":["Cross-reference to an external FAA AD (FAA AD 2009-18-07) rather than standalone text — increases dependency on another instrument for full compliance (Requirement).","Reliance on a specific Boeing Alert Service Bulletin (747-53A2349 Rev 3) to identify affected serials and procedures — requires access to manufacturer documentation (Applicability).","Multiple prior amendments and cumulative changes to inspection scope (Amendments 1–3 referenced in Background) — creates layered compliance history.","Technical requirement for repetitive inspections and repairs of structural items — entails specialised inspection techniques, engineering judgement and possible part repairs or replacements (Requirement; Background).","Operational burden on aircraft operators: scheduling, aircraft downtime, labour and parts costs, record-keeping to meet inspection intervals (Compliance).","Prescriptive effective date and mandatory compliance language reduce operational discretion for operators (Compliance).","Potentially large scope of affected aircraft types across many variants of the 747 series — broad population for enforcement (Applicability).","Risk that updated inspection areas and thresholds will require bespoke repairs or design approval, increasing interactions with regulators and OEM (Background; Requirement)."],"plain_english_summary":"This airworthiness directive requires operators of specified Boeing 747 models to carry out repetitive inspections and any necessary repairs of the fuselage internal structure in accordance with FAA AD 2009-18-07 and Boeing Alert Service Bulletin 747-53A2349 Rev 3. It takes effect on 22 October 2009. CASA issued Amendment 4 to add further inspection areas after Boeing fatigue testing identified cracking risks; operators must follow the quoted technical requirements and bear the cost and operational disruption of inspections and repairs."}},"importantCases":[],"_links":{"self":"/api/acts/ad-b747-163-amdt-4-fuselage-internal-structure","history":"/api/acts/ad-b747-163-amdt-4-fuselage-internal-structure/history","analysis":"/api/acts/ad-b747-163-amdt-4-fuselage-internal-structure/analysis","conflicts":"/api/acts/ad-b747-163-amdt-4-fuselage-internal-structure/conflicts","importantCases":"/api/acts/ad-b747-163-amdt-4-fuselage-internal-structure/important-cases","documents":"/api/acts/ad-b747-163-amdt-4-fuselage-internal-structure/documents"}}