{"id":"F2006B03148","name":"AD/B747/25 - Wing Leading Edge Flap System - Modification","slug":"ad-b747-25-wing-leading-edge-flap-system-modification","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":42520,"registerId":"commonwealth-F2006B03148-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/B747/25 - Wing Leading Edge Flap System - Modification","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/B747/25 Wing Leading Edge Flap System - Modification 1/81\n\nApplicability: All models 747.\n\n \n\nDocument: 1. FAA AD 80-19-05, Amdt. 39-3906; or\n\n \n\n2. Boeing SB No. 747-27-2204.\n\n \n\nCompliance: As per requirement document No. 1.\n\n \n\nBackground:  Investigation has revealed that a single electrical fault in the leading edge flap circuits could cause an unscheduled deployment of the flaps.\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":3,"scope_assessment":{"changed":false,"description":"The instrument's scope—mandating modification of the leading edge flap system for all Boeing 747 models to address a specific electrical-fault risk—is stated explicitly. There is no indication within the text that the applicability or substantive scope differs from its stated purpose; compliance is directed to the referenced FAA AD (Document No. 1)."},"complexity_factors":["Cross-reference to external technical documents (FAA AD 80-19-05 and Boeing SB 747-27-2204) rather than including technical detail in the instrument itself","Applicability covers all models of a complex aircraft type (Boeing 747), increasing operational scope","Compliance mandated to follow a specific external document (FAA AD) which determines the substantive requirements and schedule","Safety-critical subject matter (flight control/flap system) requiring precise technical execution, though the AD text here is brief","Limited detail in the instrument about timing, cost allocation, or alternative compliance routes, requiring consultation of the referenced material"],"plain_english_summary":"This AD requires all Boeing 747 operators/owners to modify the wing leading‑edge flap electrical system to mitigate an electrical fault that can cause unscheduled flap deployment. Compliance is mandatory by following FAA AD 80‑19‑05 (the named requirement document); the instrument delegates technical details, timing and methods to that FAA AD. Operators bear the cost and must schedule the work."},"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 specific aircraft type. It has not expanded beyond its original purpose of mandating a wing flap system modification for electrical fault protection."},"complexity_factors":["Very short document (approximately 150 words of substantive content)","Only 2 defined technical references (FAA AD and Boeing SB numbers)","No conditional logic or nested exceptions — simple universal applicability ('All models 747')","Single compliance pathway ('As per requirement document No. 1')","No cross-references to other legislation beyond the parent Civil Aviation Regulations 1998","Straightforward cause-and-effect: identified fault → mandatory modification"],"plain_english_summary":"This is an **Airworthiness Directive (AD)** — essentially a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA) for aircraft.\n\n**What it does:**\nRequires owners and operators of **all Boeing 747 aircraft** to modify the **wing leading edge flap system**. This is the movable surface on the front of the wing that extends during takeoff and landing to create more lift.\n\n**Why it matters:**\nInvestigations found a dangerous flaw: a single electrical fault in the flap circuits could cause the flaps to deploy unexpectedly during flight. Unscheduled flap deployment at the wrong time (such as during cruise) could severely damage the aircraft or cause loss of control.\n\n**Who must comply:**\nAnyone operating a Boeing 747 in Australia — all models are affected.\n\n**How to comply:**\nOperators must follow the technical instructions in either:\n- **FAA AD 80-19-05** (the US aviation safety regulator's equivalent order), or\n- **Boeing Service Bulletin 747-27-2204** (the manufacturer's official repair instructions)\n\nThis is a **safety-critical maintenance requirement** — not optional, and non-compliance grounds the aircraft."}},"importantCases":[],"_links":{"self":"/api/acts/ad-b747-25-wing-leading-edge-flap-system-modification","history":"/api/acts/ad-b747-25-wing-leading-edge-flap-system-modification/history","analysis":"/api/acts/ad-b747-25-wing-leading-edge-flap-system-modification/analysis","conflicts":"/api/acts/ad-b747-25-wing-leading-edge-flap-system-modification/conflicts","importantCases":"/api/acts/ad-b747-25-wing-leading-edge-flap-system-modification/important-cases","documents":"/api/acts/ad-b747-25-wing-leading-edge-flap-system-modification/documents"}}