{"id":"F2007L00353","name":"AD/B747/354 - Crown Crease Beam","slug":"ad-b747-354-crown-crease-beam","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":63354,"registerId":"commonwealth-F2007L00353-current","compilationNumber":null,"startDate":"2026-04-02","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/B747/354 | Crown Crease Beam | 3/2007 |\n| ----------- | ----------------- | ------ |\n\n| Applicability: | Model 747-100B SUD, -200B, -300, -400, -400D, and 747SP series aircraft; as identified in Boeing Alert Service Bulletin 747-53A2591 original issue, or later FAA approved revision.                                                                  |\n| -------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement:   | Action in accordance with the technical requirements of FAA AD 2007-01-09 Amdt 39-14881.                                                                                                                                                             |\n| Compliance:    | As specified in the Requirement document, with a revised effective date of15 March 2007.                                                                                                                                                             |\n|                | This Airworthiness Directive becomes effective on 15 March 2007.                                                                                                                                                                                     |\n| Background:    | The FAA received a report of cracking of the crown crease beam on two Model 747 aircraft. Such cracking, unless detected and corrected, could expand and result in depressurisation and inability of the airframe structure to sustain flight loads. |\n\n![](image.001.png)  \nDavid Villiers  \nDelegate of the Civil Aviation Safety Authority\n\n1 February 2007","sortOrder":0},{"sectionNumber":"AD/B747/354","sectionType":"part","heading":"AD/B747/354","content":"## AD/B747/354","sortOrder":1},{"sectionNumber":"Crown Crease Beam","sectionType":"part","heading":"Crown Crease Beam","content":"## Crown Crease Beam","sortOrder":2},{"sectionNumber":"3/2007","sectionType":"part","heading":"3/2007","content":"## 3/2007","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":2,"scope_assessment":{"changed":false,"description":"This is a standard airworthiness directive with a narrow, specific purpose: addressing a known structural defect in particular aircraft models. The scope remains tightly focused on the crown crease beam cracking issue as originally identified."},"complexity_factors":["Very short document (under 300 words)","Only one substantive requirement: comply with an external FAA directive","No defined terms section — relies entirely on the referenced FAA document for technical details","Simple conditional logic: if you operate these specific aircraft models, you must comply","Single cross-reference to external document (FAA AD 2007-01-09)","No nested exceptions or conditional compliance pathways"],"plain_english_summary":"This CASA Airworthiness Directive makes FAA AD 2007-01-09 legally binding in Australia, requiring inspections and repairs for cracking in the crown-crease beam of certain Boeing 747 types (747-100B SUD, -200B, -300, -400, -400D, -SP). It targets a structural defect found by the FAA that could cause cabin depressurisation or structural failure if untreated. The requirement has applied since 15 March 2007."},"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":false,"description":"The AD adopts the FAA's requirements for the listed 747 models and does not alter applicability or substantive technical requirements; the instrument only sets Australia’s enforcement and a revised effective date of 15 March 2007 (see 'Requirement' and 'Compliance')."},"complexity_factors":["Cross-reference to external FAA AD 2007-01-09 for technical mandates (requires consulting another instrument)","Dependence on Boeing Alert Service Bulletin 747-53A2591 for applicability and technical detail","Multiple aircraft models covered (several 747 variants) increasing fleet-level compliance planning","Safety-critical structural inspections and potential repairs create variable cost and scheduling burdens","Limited procedural detail in the CASA instrument itself (it delegates technical steps to the FAA AD/SB)","Revised effective date (administrative change) requires timetable adjustment by operators"],"plain_english_summary":"This Airworthiness Directive requires operators of listed Boeing 747 variants to carry out the inspections and corrective actions specified in FAA AD 2007-01-09 and Boeing Alert Service Bulletin 747-53A2591. It is enforced by the Civil Aviation Safety Authority and becomes effective on 15 March 2007.\n\nAircraft operators must perform the mandated inspections/repairs and bear the costs of those works to detect and correct cracking of the crown crease beam that could cause depressurisation or loss of structural load capability."}},"importantCases":[],"_links":{"self":"/api/acts/ad-b747-354-crown-crease-beam","history":"/api/acts/ad-b747-354-crown-crease-beam/history","analysis":"/api/acts/ad-b747-354-crown-crease-beam/analysis","conflicts":"/api/acts/ad-b747-354-crown-crease-beam/conflicts","importantCases":"/api/acts/ad-b747-354-crown-crease-beam/important-cases","documents":"/api/acts/ad-b747-354-crown-crease-beam/documents"}}