{"id":"F2005L03572","name":"AD/B737/266 - Upper and Lower Skins of the Fuselage Lap Joint","slug":"ad-b737-266-upper-and-lower-skins-of-the-fuselage-lap-joint","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":39142,"registerId":"commonwealth-F2005L03572-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"Boeing 737 Series Aeroplanes","sectionType":"division","heading":"Boeing 737 Series Aeroplanes","content":"### Boeing 737 Series Aeroplanes\n\n| AD/B737/266 | Upper and Lower Skins ofthe Fuselage Lap Joint | 13/2005 |\n| ----------- | ---------------------------------------------- | ------- |\n\n| Applicability: | Model 737-100, -200, and -200C series aircraft, line numbers 1 through 291.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       |\n| -------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement:   | Action in accordance with the technical requirements of FAA AD 2003-23-03Amdt 39-13367.Note: Boeing Alert Service Bulletins 737-53A1224 original issue, and Revision 1, or later FAA approved revisions, refer.                                                                                                                                                                                                                                                                                                                                                                                                                                                   |\n| Compliance:    | As specified in the Requirement document.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         |\n|                | This Airworthiness Directive becomes effective on 22 December 2005.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               |\n| Background:    | The FAA received a report of an in-flight rapid decompression of a Model 737 series aircraft. Investigation revealed that the skin above the forward entry door was separated at the stringer S-4R lap joint, with a 28-inch tear running along the lap joint. Further investigation revealed that numerous scratches on the skin of the lap joint had initiated fatigue cracks and subsequent tearing of the skin. Fatigue cracking and corrosion was also detected in other lap joints at various locations. Such discrepancies, if not corrected, could result in sudden fracture and failure of a lap joint and rapid decompression of the aircraft fuselage. |\n\n![](image.001.png)  \nDavid Villiers  \nDelegate of the Civil Aviation Safety Authority\n\n11 November 2005","sortOrder":0},{"sectionNumber":"AD/B737/266","sectionType":"part","heading":"AD/B737/266","content":"## AD/B737/266","sortOrder":1},{"sectionNumber":"Upper and Lower Skins ofthe Fuselage Lap","sectionType":"part","heading":"Upper and Lower Skins ofthe Fuselage Lap Joint","content":"## Upper and Lower Skins of  \nthe Fuselage Lap Joint","sortOrder":2},{"sectionNumber":"13/2005","sectionType":"part","heading":"13/2005","content":"## 13/2005","sortOrder":3}],"analysis":{"flash_summary":{"complexity_score":6,"scope_assessment":{"changed":false,"description":"This AD adopts the FAA AD and Boeing Alert Service Bulletin requirements for specified early-model 737s (models -100, -200, -200C; line numbers 1–291). The instrument does not expand the listed applicability or impose additional types of actions beyond those referenced, so scope remains aligned with the FAA/Boeing documents cited in the Requirement."},"complexity_factors":["Reliance on external normative documents (FAA AD 2003-23-03 and Boeing Alert Service Bulletin 737-53A1224) creates cross-reference dependency and requires access to and interpretation of those technical documents.","Technical subject-matter (fatigue cracking, lap-joint inspection and repair) requires specialised engineering and maintenance capability.","Applicability is narrowly defined (specific models and line numbers 1–291), increasing identification and tracking burden for operators with mixed fleets.","Compliance timing and detailed procedures are delegated to the referenced Requirement document rather than fully specified here, adding interpretive complexity.","Potential for operational disruption (aircraft out-of-service for inspection/repair) raises logistical and cost-management issues for operators.","Regulatory enforcement relies on CASA adopting and enforcing FAA-origin requirements, creating inter-jurisdictional procedural dependencies."],"plain_english_summary":"This Airworthiness Directive requires operators of early Boeing 737s (models -100, -200, -200C; line numbers 1–291) to inspect and repair fuselage lap joints in accordance with FAA AD 2003-23-03 and Boeing Alert Service Bulletin 737-53A1224. It becomes effective 22 December 2005.\n\nThe action follows reports of a 28‑inch tear and fatigue/corrosion at a forward-entry-door lap joint; the directive places inspection and repair costs and potential operational disruption on aircraft operators, and enforces maintenance via regulator-referenced technical documents."},"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 specific aircraft models. It has not expanded beyond its original safety purpose."},"complexity_factors":["Very short document (approximately 250 words of substantive content)","Only 1 defined term implicitly used ('line numbers' referring to production sequence)","No cross-references to other Australian legislation — only references to external FAA directive and Boeing technical document","Simple conditional structure: single applicability test (model and line number) triggers single requirement","No exceptions, exemptions, or nested conditions","Technical complexity is outsourced to external Boeing service bulletin (not contained in this instrument itself)"],"plain_english_summary":"This CASA Airworthiness Directive mandates inspections and repairs to the fuselage lap joints on early Boeing 737-100/200/200C aircraft (line numbers 1–291) to address scratches, corrosion and fatigue cracks that can cause sudden tearing and rapid decompression. It requires compliance with Boeing Alert Service Bulletin 737-53A1224 (or approved revisions) and follows FAA technical guidance; the AD took effect 22 December 2005."},"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"}},"importantCases":[],"_links":{"self":"/api/acts/ad-b737-266-upper-and-lower-skins-of-the-fuselage-lap-joint","history":"/api/acts/ad-b737-266-upper-and-lower-skins-of-the-fuselage-lap-joint/history","analysis":"/api/acts/ad-b737-266-upper-and-lower-skins-of-the-fuselage-lap-joint/analysis","conflicts":"/api/acts/ad-b737-266-upper-and-lower-skins-of-the-fuselage-lap-joint/conflicts","importantCases":"/api/acts/ad-b737-266-upper-and-lower-skins-of-the-fuselage-lap-joint/important-cases","documents":"/api/acts/ad-b737-266-upper-and-lower-skins-of-the-fuselage-lap-joint/documents"}}