{"id":"F2006B03274","name":"AD/B747/96 - Drain Mast Assemblies","slug":"ad-b747-96-drain-mast-assemblies","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":42702,"registerId":"commonwealth-F2006B03274-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/B747/96 - Drain Mast Assemblies","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/B747/96 Drain Mast Assemblies 7/91\n\nApplicability: Boeing 747 series aeroplanes as listed in Boeing Alert Service Bulletin 747-38A2077, dated 30 August 1990.\n\n \n\nRequirement: Action in accordance with the Technical Requirements of FAA AD 91-09-11.\n\n \n\nNote: FAA AD 91-09-11 refers to Boeing Alert Service Bulletin 747-38A2077, dated 30 August 1990.\n\n \n\nCompliance: Required within 12 months from 11 July 1991.\n\n \n\nBackground: FAA AD action prompted by two reports of fire which may have been caused by the contact of foreign material with drain mast heater elements. This condition, if not corrected, could result in structural damage to the fuselage skin, frame, and stringers, and possible uncontrolled fire.\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, single-issue airworthiness directive addressing a specific mechanical defect in a specific aircraft type. It has not expanded beyond its original purpose of mandating drain mast assembly inspections and repairs."},"complexity_factors":["Extremely short document (approximately 150 words of substantive content)","Only 1 defined term implicitly referenced (FAA AD 91-09-11)","No conditional logic or nested exceptions — single straightforward requirement","No cross-references to other legislation beyond a single external FAA directive","Simple linear structure: applicability → requirement → compliance deadline → background","Technical content is entirely delegated to external documents (FAA AD and Boeing Service Bulletin)"],"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:**\nOrders owners and operators of **Boeing 747 aircraft** to inspect and fix a specific problem with **drain mast assemblies** — these are components that drain fluids (like water or fuel) from the aircraft. The issue involves the **heater elements** in these drains, which can ignite foreign material and cause fires.\n\n**Who it affects:**\n- Airlines and operators flying Boeing 747 series planes\n- Specifically those aircraft covered by Boeing Alert Service Bulletin 747-38A2077\n\n**What must be done:**\nOperators must follow the technical instructions in **FAA AD 91-09-11** (an American aviation safety order that CASA is adopting here). This involves checking and correcting the drain mast assemblies to prevent fire risks.\n\n**Why it matters:**\nTwo fires had already been reported due to this defect. Left unfixed, it could cause:\n- Structural damage to the aircraft's fuselage (the main body of the plane)\n- Uncontrolled fire in flight\n\n**Deadline:**\nThe work had to be completed within **12 months from 11 July 1991**.\n\n**Key point:** This document doesn't contain the actual technical instructions — it simply references the American FAA directive and Boeing's service bulletin. Operators must obtain those separate documents to know exactly what mechanical work to perform."},"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"Scope remains limited to the Boeing 747 series aeroplanes listed in Boeing Alert Service Bulletin 747‑38A2077 and continues to require the technical actions specified in FAA AD 91‑09‑11, to be completed within the original 12‑month compliance window. No expansion or narrowing of applicability is indicated in the text."},"complexity_factors":["Narrow applicability to specific Boeing 747 models listed in Boeing Alert Service Bulletin 747‑38A2077 (Applicability).","Delegation of technical content to an external instrument: FAA AD 91‑09‑11 and Boeing Alert Service Bulletin (Requirement; Note).","Fixed statutory compliance deadline: 12 months from 11 July 1991, creating a clear but time‑bound obligation (Compliance).","Work is technical and requires certified maintenance/engineering resources, imposing operational and cost burdens on operators (Requirement: \"Technical Requirements\").","Underlying safety consequence is high (risk of fuselage structural damage and uncontrolled fire), which drives the mandatory nature of the action (Background)."],"plain_english_summary":"This airworthiness directive requires operators of Boeing 747 aeroplanes listed in Boeing Alert Service Bulletin 747‑38A2077 (30 Aug 1990) to carry out the technical measures set out in FAA AD 91‑09‑11 to address drain‑mast heater/fire risks. Compliance is mandatory within 12 months from 11 July 1991.\n\nIt affects aircraft owners and maintenance organisations, who must perform inspections/repairs and bear the compliance costs. The directive relies on FAA and Boeing service documents for technical detail and aims to prevent fuselage structural damage and possible uncontrolled fire."}},"importantCases":[],"_links":{"self":"/api/acts/ad-b747-96-drain-mast-assemblies","history":"/api/acts/ad-b747-96-drain-mast-assemblies/history","analysis":"/api/acts/ad-b747-96-drain-mast-assemblies/analysis","conflicts":"/api/acts/ad-b747-96-drain-mast-assemblies/conflicts","importantCases":"/api/acts/ad-b747-96-drain-mast-assemblies/important-cases","documents":"/api/acts/ad-b747-96-drain-mast-assemblies/documents"}}