{"id":"F2006B02721","name":"AD/B727/21 - Inboard Trailing Edge Upper Wing Panel - Replacement","slug":"ad-b727-21-inboard-trailing-edge-upper-wing-panel-replacement","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":42037,"registerId":"commonwealth-F2006B02721-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/B727/21 - Inboard Trailing Edge Upper Wing Panel - Replacement","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 727 Series Aeroplanes\n\n \n\nAD/B727/21 Inboard Trailing Edge Upper Wing Panel - Replacement\n\n\n2/66\n\n \n\nApplicability: All models. Document: Boeing SB No. 57-58.\n\nCompliance: Before 6000 hours total time in service.\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\n \n\n \n\n \n\n \n\n \n\n \n\n \n","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"The supplied text sets a single, specific mandatory action (replacement of the inboard trailing edge upper wing panel), applicable to all Boeing 727 models, to be completed before 6,000 hours TIS (Applicability; Compliance; Document). The excerpt contains no information indicating that the scope of the requirement has been expanded or narrowed relative to any prior instrument or original intent; therefore there is no evidence in the provided text that the scope has changed."},"complexity_factors":["Narrow, single-action requirement (replace a specific panel) reduces procedural complexity.","Clear, single deadline (before 6,000 hours total time in service) simplifies compliance timing.","Reference to an external procedural document (Boeing SB No. 57-58) requires operators to consult that bulletin for technical steps, increasing practical complexity modestly.","Regulatory authority and enforcement are established under Part 39, but the excerpt omits any alternative-compliance or enforcement detail, leaving some implementation ambiguity."],"plain_english_summary":"This Airworthiness Directive from CASA requires operators of all Boeing 727 models to replace the inboard trailing‑edge upper wing panel using Boeing Service Bulletin No. 57‑58 before each aeroplane reaches 6,000 total flight hours. Operators bear the direct costs and must schedule parts and maintenance to meet the uniform, time‑certain compliance obligation."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a standard, narrow airworthiness directive focused on a specific technical repair. It has not expanded beyond its original purpose of mandating a single safety modification to Boeing 727 wing panels."},"complexity_factors":["Extremely short document (approximately 150 words)","Only 2 substantive operative provisions (applicability and compliance)","No defined terms section","No cross-references to other legislation beyond the enabling Civil Aviation Regulations 1998","Single, unambiguous compliance deadline (6000 hours time in service)","References only one external technical document (Boeing SB 57-58)"],"plain_english_summary":"This is an **Airworthiness Directive (AD)** — a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA). It requires owners and operators of **Boeing 727 aircraft** to replace a specific part: the **inboard trailing edge upper wing panel**.\n\n**Who it affects:**\n- Anyone who owns or operates a Boeing 727 series aircraft in Australia\n- Maintenance organisations servicing these aircraft\n\n**What it requires:**\n- The wing panel must be replaced **before the aircraft reaches 6,000 hours of total flight time**\n- The replacement must follow the technical instructions in **Boeing Service Bulletin No. 57-58**\n\n**Why it matters:**\nAirworthiness Directives are legally binding safety instructions. They are issued when a safety defect or unsafe condition is discovered in an aircraft type. Failing to comply means the aircraft cannot legally fly in Australian airspace. This particular AD addresses a structural issue with the wing panel that could affect flight safety if left unaddressed."}},"importantCases":[],"_links":{"self":"/api/acts/ad-b727-21-inboard-trailing-edge-upper-wing-panel-replacement","history":"/api/acts/ad-b727-21-inboard-trailing-edge-upper-wing-panel-replacement/history","analysis":"/api/acts/ad-b727-21-inboard-trailing-edge-upper-wing-panel-replacement/analysis","conflicts":"/api/acts/ad-b727-21-inboard-trailing-edge-upper-wing-panel-replacement/conflicts","importantCases":"/api/acts/ad-b727-21-inboard-trailing-edge-upper-wing-panel-replacement/important-cases","documents":"/api/acts/ad-b727-21-inboard-trailing-edge-upper-wing-panel-replacement/documents"}}