{"id":"F2006B03025","name":"AD/B747/124 - H-11 Steel Bolts","slug":"ad-b747-124-h-11-steel-bolts","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":42384,"registerId":"commonwealth-F2006B03025-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/B747/124 - H-11 Steel Bolts","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/B747/124 H-11 Steel Bolts 7/94\n\nApplicability: Model 747 series aircraft with line numbers 641 through 708, excluding Model 747- 400 series aircraft.\n\n \n\nRequirement: Action in accordance with the technical requirements of FAA AD 94-07-06 Amendment 39-8864.\n\n \n\nNote: Boeing SB 747-51-2048 refers.\n\n \n\nCompliance: As specified in the Requirement Document.\n\n \n\nBackground: Reports were received of cracked and fractured H-11 steel bolts installed at certain locations of the airframe structure. The actions specified in this Directive are intended to prevent the failure of attachment bolts at critical locations.\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 mechanical defect in a defined aircraft population. It has not expanded beyond its original purpose of mandating bolt inspection/replacement."},"complexity_factors":["Very short document (under 200 words)","Only 1 defined applicability criterion (line numbers 641–708)","Single requirement referencing an external FAA document rather than spelling out technical steps","No nested exceptions or conditional logic — straightforward compliance obligation","Minimal cross-referencing (only one Boeing Service Bulletin mentioned in a note)"],"plain_english_summary":"This is an **Airworthiness Directive (AD)** — essentially a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA). It applies to specific Boeing 747 aircraft (production line numbers 641–708, but not the newer 747-400 models).\n\n**What it does:**\n- Requires airlines and aircraft operators to inspect and replace certain **H-11 steel bolts** used in the airframe structure of these planes.\n- The bolts have been found to crack and fracture, which could cause critical structural failures.\n- Operators must follow the technical instructions set out in a corresponding US Federal Aviation Administration (FAA) directive (AD 94-07-06).\n\n**Who it affects:**\n- Owners and operators of specific older Boeing 747 aircraft registered in Australia.\n- Maintenance engineers responsible for airframe inspections.\n\n**Why it matters:**\n- Cracked bolts in critical structural locations could lead to catastrophic failure during flight. This directive prevents that by mandating proactive replacement before failure occurs."},"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":false,"description":"The Directive’s stated scope is narrow and limited to Model 747 aircraft with line numbers 641–708, excluding the 747-400 series, and it requires actions specified in an FAA AD and a Boeing service bulletin. The text presents this scope as the response to reported cracked and fractured H-11 steel bolts. There is no indication within the instrument that the scope has been broadened or narrowed beyond that stated intent."},"complexity_factors":["References external technical documents (FAA AD 94-07-06 and Boeing SB 747-51-2048) for all procedural detail, requiring users to obtain and reconcile multiple sources.","Narrow applicability (specific line numbers and explicit exclusion of -400 series) requires accurate aircraft identification and record checks.","Safety-critical, technical subject matter (bolt inspection and replacement) typically requires specialised maintenance personnel and parts.","Compliance is mandated but the AD text delegates procedural specifics, limiting interpretive discretion but increasing procedural dependence on external documents.","Potential operational impact (aircraft downtime) creates scheduling and logistical complexity for operators."],"plain_english_summary":"This Airworthiness Directive requires owners/operators of specific Boeing 747s (line numbers 641–708; excludes -400 series) to follow the inspection, corrective-action and replacement measures set out in FAA AD 94-07-06 (with Boeing Service Bulletin 747-51-2048 noted). It responds to reported cracked H‑11 steel bolts and aims to prevent attachment-bolt failures. Compliance costs, downtime and procedural specifics fall to the affected operators, who must obtain and follow the referenced technical documents."}},"importantCases":[],"_links":{"self":"/api/acts/ad-b747-124-h-11-steel-bolts","history":"/api/acts/ad-b747-124-h-11-steel-bolts/history","analysis":"/api/acts/ad-b747-124-h-11-steel-bolts/analysis","conflicts":"/api/acts/ad-b747-124-h-11-steel-bolts/conflicts","importantCases":"/api/acts/ad-b747-124-h-11-steel-bolts/important-cases","documents":"/api/acts/ad-b747-124-h-11-steel-bolts/documents"}}