{"id":"F2006B03251","name":"AD/B747/72 - Fuselage Crown Crease Beam","slug":"ad-b747-72-fuselage-crown-crease-beam","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":42675,"registerId":"commonwealth-F2006B03251-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/B747/72 - Fuselage Crown Crease Beam","content":"---\nmeta-content-style-type: text/css\nmeta-content-type: application/xhtml+xml; charset=utf-8\nmeta-generator: Aspose.Words for .NET 22.10.0\n---\n\n?xml version=\"1.0\" encoding=\"utf-8\" standalone=\"no\"?>\n\nCOMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n \n\n![](image.001.png)  Boeing 747 Series Aeroplanes\n\n \n\nAD/B747/72 Fuselage Crown Crease Beam 10/89\n\nApplicability:  Line numbers 66 through 603 except models 747 SP, 747-200 SUD and 747-300 SUD.\n\n \n\nRequirement:  Perform periodic detailed visual and dye penetrant inspections of the body crown crease beam for cracks, in accordance with Boeing Service Bulletin 747-53-2297 Revision 1, dated 26 January 1989. FAA AD 89-08-03 also refers.\n\n \n\nCompliance: In accordance with FAA AD 89-08-03, except that pressurised flight cycles may be taken in lieu of landings.\n\n \n\nBackground: Five operators have reported cracks in the subject area, which has been determined to be critical to the aircrafts structural integrity. Hence an inspection program which will continue throughout the life of the affected aircraft is prescribed.\n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, targeted safety directive addressing a specific structural defect in specific aircraft. It has not expanded beyond its original purpose of mandating inspections for fuselage crown crease beam cracks."},"complexity_factors":["Single, specific technical requirement with clear reference to external Boeing Service Bulletin","Only one defined applicability criterion (line numbers 66-603 with three model exclusions)","Minimal conditional logic — essentially 'inspect this part, this way, on this schedule'","Short document (approximately 150 words of substantive content)","Single cross-reference to FAA AD 89-08-03 for compliance timing","No nested exceptions or layered definitions"],"plain_english_summary":"This CASA Airworthiness Directive requires operators of specified Boeing 747s (line numbers 66–603, excluding 747 SP and SUD variants) to carry out recurring detailed visual and dye‑penetrant inspections of the fuselage crown crease beam. Prompted by multiple crack discoveries, the measure protects structural integrity under repeated pressurisation cycles; CASA allows compliance to be measured in pressurised flight cycles rather than landings."},"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":false,"description":"The directive, as written, limits application to specified line numbers and model exceptions and prescribes periodic inspections for life of the aircraft. The text provides no indication that the scope has been broadened or narrowed from an earlier instrument; it treats the specified applicability and lifetime inspection programme as the operative scope."},"complexity_factors":["Applicability defined by production line numbers with model exceptions (source: \"Applicability: Line numbers 66 through 603 except models 747 SP, 747-200 SUD and 747-300 SUD\").","External incorporation: compliance depends on following Boeing Service Bulletin 747-53-2297 Rev 1 and FAA AD 89-08-03 (source: \"Requirement\" and \"FAA AD 89-08-03 also refers\").","Technical inspection methods specified (detailed visual and dye penetrant), requiring specialised skills, equipment and aircraft access (source: \"Perform periodic detailed visual and dye penetrant inspections\").","Operational compliance substitution: allows pressurised flight cycles to be counted instead of landings, which affects monitoring and record-keeping systems (source: \"Compliance: ... pressurised flight cycles may be taken in lieu of landings\").","Temporal scope: inspection programme is ongoing throughout the life of the aircraft, implying recurring costs and long-term maintenance planning (source: \"Background: ... inspection program which will continue throughout the life of the affected aircraft\").","Safety-critical context: area is described as critical to structural integrity, increasing the stakes for inspection accuracy and timely corrective action (source: \"which has been determined to be critical to the aircrafts structural integrity\")."],"plain_english_summary":"This Airworthiness Directive requires operators of Boeing 747 aeroplanes (line numbers 66–603, excluding 747 SP, 747‑200 SUD and 747‑300 SUD) to carry out periodic detailed visual and dye‑penetrant inspections of the fuselage crown crease beam for cracks, following Boeing Service Bulletin 747‑53‑2297 Revision 1 and FAA AD 89‑08‑03. Pressurised flight cycles may be used in lieu of landings for counting compliance. The inspections are required to continue for the life of affected aircraft."}},"importantCases":[],"_links":{"self":"/api/acts/ad-b747-72-fuselage-crown-crease-beam","history":"/api/acts/ad-b747-72-fuselage-crown-crease-beam/history","analysis":"/api/acts/ad-b747-72-fuselage-crown-crease-beam/analysis","conflicts":"/api/acts/ad-b747-72-fuselage-crown-crease-beam/conflicts","importantCases":"/api/acts/ad-b747-72-fuselage-crown-crease-beam/important-cases","documents":"/api/acts/ad-b747-72-fuselage-crown-crease-beam/documents"}}