{"id":"F2006B03254","name":"AD/B747/76 Amdt 1 - H-11 Steel Bolts","slug":"ad-b747-76-amdt-1-h-11-steel-bolts","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":42678,"registerId":"commonwealth-F2006B03254-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/B747/76 Amdt 1 - H-11 Steel Bolts","content":"COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 \\- 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n![](image.001.png)  \nBoeing 747 Series Aeroplanes\n\nAD/B747/76\n\nAmdt 1\n\n  \nH-11 Steel Bolts 7/90\n\nApplicability: Model 747 with line numbers 001 through 648.\n\nRequirement: 1. Visually inspect H-11 steel bolts for cracks or fractures at locations in accordance with Boeing SB 747-51-2043 Rev 1.\n\n2. Replace all H-11 steel bolts with Inconel 718 bolts at locations in accordance with Boeing SB 747-51-2043 Rev 1.\n\nNote: FAA AD 89-23-07 refers.\n\nCompliance: For Requirement 1: Prior to exceeding 4 years since date of manufacture or within 15 calendar months after 22 February 1990, whichever occurs later, and thereafter at intervals not exceeding 18 calendar months until H-11 bolts are replaced with Inconel 718 bolts.\n\nFor Requirement 2: Prior to 22 February 1994.\n\nBackground: Country of origin AD. Fracture or cracking of H-11 steel bolts at critical locations has been reported. This condition if not corrected could result in severe structural damage. Amendment 1 references the latest revision to the Requirement document.","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This is an amendment to an existing Airworthiness Directive, but it does not expand scope. Amendment 1 simply updates the reference to the latest revision of Boeing's technical document (SB 747-51-2043 Rev 1). The original purpose — addressing H-11 steel bolt failures through inspection and replacement — remains unchanged."},"complexity_factors":["Short, single-purpose directive with only 2 requirements","Minimal defined terms (only standard aviation references like 'line numbers' and 'SB' for Service Bulletin)","Simple conditional logic for compliance dates (whichever occurs later)","Single cross-reference to FAA AD 89-23-07 and Boeing Service Bulletin","No nested exceptions or complex sub-clauses","Total length: approximately 200 words"],"plain_english_summary":"This CASA Airworthiness Directive requires operators of early Boeing 747s (line numbers 001–648) to inspect H‑11 steel fasteners for cracking and ultimately replace them with more durable Inconel 718 bolts. It mandates compliance with Boeing's service instructions (updated in this amendment) to prevent catastrophic structural failure and aligns with the FAA's related AD."},"flash_summary":{"complexity_score":5,"scope_assessment":{"changed":false,"description":"Amendment 1 updates the referenced Boeing service bulletin revision and clarifies requirements and intervals but does not broaden applicability beyond Model 747 line numbers 001–648. The AD keeps the same affected fleet and adds a replacement deadline and inspection schedule rather than extending scope."},"complexity_factors":["Applicability limited to Model 747, line numbers 001–648 (narrow but technically specific).","Two-tiered requirements: recurring visual inspections (Requirement 1) plus mandatory full replacement (Requirement 2).","Time-based compliance windows combining manufacture-date thresholds and fixed calendar deadlines (Compliance: pre-4 years or within 15 months after 22 Feb 1990; thereafter 18‑month intervals; replacement by 22 Feb 1994).","Cross-reference to an external service document (Boeing SB 747-51-2043 Rev 1) as the procedural standard for inspection/locations, adding reliance on a non-statutory document.","Reference to a foreign regulator's AD (FAA AD 89-23-07), creating dependence on overseas certification actions.","Technical judgement required for visual detection of cracks (potential for variable inspection accuracy and rework), affecting maintenance workload and operator costs.","Replacement material specification (Inconel 718) imposes procurement and compatibility requirements.","Record-keeping and scheduling burden for operators to track manufacture dates, inspection intervals and the mandated replacement deadline.","Regulatory amendment character: Amendment 1 updates the referenced service bulletin revision rather than changing fleet scope, requiring attention to the current SB revision."],"plain_english_summary":"This airworthiness directive requires operators of Boeing 747 aeroplanes (line numbers 001–648) to inspect specific H‑11 steel bolts for cracking and to replace them with Inconel 718 bolts. The AD sets inspection intervals tied to manufacture date and a firm replacement deadline. The stated purpose is to prevent bolt fracture and ensuing structural damage; operators pay for inspections, parts and downtime and must follow Boeing SB 747-51-2043 Rev 1 as the compliance method."}},"importantCases":[],"_links":{"self":"/api/acts/ad-b747-76-amdt-1-h-11-steel-bolts","history":"/api/acts/ad-b747-76-amdt-1-h-11-steel-bolts/history","analysis":"/api/acts/ad-b747-76-amdt-1-h-11-steel-bolts/analysis","conflicts":"/api/acts/ad-b747-76-amdt-1-h-11-steel-bolts/conflicts","importantCases":"/api/acts/ad-b747-76-amdt-1-h-11-steel-bolts/important-cases","documents":"/api/acts/ad-b747-76-amdt-1-h-11-steel-bolts/documents"}}