{"id":"F2006B03270","name":"AD/B747/92 - Horizontal Stabiliser","slug":"ad-b747-92-horizontal-stabiliser","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":42694,"registerId":"commonwealth-F2006B03270-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/B747/92 - Horizontal Stabiliser","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/B747/92 Horizontal Stabiliser 6/91\n\nApplicability: Model 747 series with line numbers 002 through 226.\n\n \n\nRequirement: Action in accordance with the technical requirements of FAA AD 91-05-17 Amdt 39- 6917.\n\n \n\nNote: Boeing Alert SB 747-53A 2332 refers.\n\n \n\nCompliance: As specified in the Requirement Document with a revised effective date of 13 June 1991 for Australian registered aircraft.\n\n \n\nBackground: The FAA has received reports of additional cracking detected by the inspections required by a current Airworthiness Directive. This condition, if not corrected, could result in loss of the horizontal stabilizer. Effective date required by the FAA is extended by two months.\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 standard, narrow airworthiness directive focused on a specific safety defect in specific aircraft. It has not expanded beyond its original purpose of mandating inspection and repair of horizontal stabiliser cracking."},"complexity_factors":["Very short document (under 200 words)","Only 1 defined applicability criterion (line numbers 002-226)","Single requirement: comply with external FAA document","No nested conditions, exceptions, or cross-references within the instrument itself","Minimal legislative machinery — essentially a pointer to US technical standards"],"plain_english_summary":"This is an **Airworthiness Directive (AD)** — essentially a mandatory safety order for aircraft. It applies to specific **Boeing 747 aeroplanes** (those built with line numbers 002 through 226, which covers early production models).\n\n**What it does:**\n- Requires owners and operators of these aircraft to follow specific technical instructions from the US Federal Aviation Administration (FAA) to inspect and fix potential cracking in the **horizontal stabiliser** — the large wing at the tail that keeps the plane level.\n- The cracking was found during earlier inspections. If left unfixed, it could cause the stabiliser to fail, potentially leading to loss of control of the aircraft.\n\n**Who it affects:**\n- Australian-registered Boeing 747 operators with these specific early-model aircraft.\n\n**Why it matters:**\n- This is a **critical safety issue**. The horizontal stabiliser is essential for flight control. The directive extends the original US deadline by two months for Australian operators, giving them until **13 June 1991** to comply.\n\n**Key reference:** Operators must follow **FAA AD 91-05-17** and can also check **Boeing Alert Service Bulletin 747-53A2332** for technical details."},"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":true,"description":"The instrument adopts the FAA AD's technical requirements but alters the timing for Australian aircraft by providing a revised effective date (13 June 1991) — the text states the FAA's effective date is extended by two months and sets the Australian date accordingly. Apart from the timing adjustment and the line‑numbered applicability (002–226), the substantive technical scope follows FAA AD 91‑05‑17 as referenced."},"complexity_factors":["Cross-reference to an external FAA AD (FAA AD 91‑05‑17 Amdt 39‑6917): the Australian instrument mandates compliance with another regulator's technical document rather than reproducing procedures, so operators must obtain and follow that external material.","Reference to manufacturer service information (Boeing Alert SB 747‑53A2332): requires coordination between regulator, manufacturer guidance, and operator maintenance practice.","Narrow applicability by line number (\"Model 747 series with line numbers 002 through 226\"): limits which fleet aircraft are affected but requires operators to verify airframe lineage.","Revised effective date (\"revised effective date of 13 June 1991 for Australian registered aircraft\"): timing differs from the FAA; Australian operators must track the amended compliance start.","Safety‑critical technical inspections and possible corrective actions: implies direct maintenance cost, downtime, parts and certified personnel to detect and repair cracking.","Compliance burden is not detailed in this text (\"Compliance: As specified in the Requirement Document\"): enforcement requires consulting the Requirement Document/FAA AD for intervals, methods and corrective steps.","Operational risk and substitution effects: inspections/repairs can ground aeroplanes, affecting schedules and maintenance resource allocation.","Limited discretion in this AD: it mandates following the FAA document, leaving little room for alternative methods unless that document allows them."],"plain_english_summary":"This Airworthiness Directive requires operators of Boeing 747 series aeroplanes (line numbers 002–226) to carry out the inspections and corrective work set out in FAA AD 91‑05‑17 (Amdt 39‑6917). It applies to Australian‑registered aircraft and sets a revised effective date of 13 June 1991 after reports of additional horizontal stabiliser cracking that, if not fixed, could lead to loss of the stabiliser."}},"importantCases":[],"_links":{"self":"/api/acts/ad-b747-92-horizontal-stabiliser","history":"/api/acts/ad-b747-92-horizontal-stabiliser/history","analysis":"/api/acts/ad-b747-92-horizontal-stabiliser/analysis","conflicts":"/api/acts/ad-b747-92-horizontal-stabiliser/conflicts","importantCases":"/api/acts/ad-b747-92-horizontal-stabiliser/important-cases","documents":"/api/acts/ad-b747-92-horizontal-stabiliser/documents"}}