{"id":"F2006B03231","name":"AD/B747/50 - Inboard Pylon Upper Link","slug":"ad-b747-50-inboard-pylon-upper-link","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":42655,"registerId":"commonwealth-F2006B03231-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/B747/50 - Inboard Pylon Upper Link","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/B747/50  Inboard Pylon Upper Link 6/86 Applicability:              All models, line No’s 1 to 616, with JT9D-3 or -7, or CF6-45 or -50 engine struts. Requirement:               Inspect in accordance with:\n\n1. FAA AD 86-07-06 (Sections A and C) or,\n\n\n \n\n2.    Boeing Service Bulletin 747-54-2111, Revision 1.\n\n \n\nCompliance: As detailed in Requirement Document No. 1. until modified in accordance with Requirement Document No.2.\n\n \n\nBackground: Cracks have occurred in the forward lug of the inboard pylon upper link. If not corrected, this could result in separation of an engine from an aircraft.\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 focused on a specific mechanical defect in a specific aircraft type. It has not expanded beyond its original purpose of addressing the cracked pylon upper link issue identified in 1986."},"complexity_factors":["Very short document (approximately 150 words of substantive content)","Only 4 defined applicability criteria (aircraft models, line numbers, engine types)","Simple binary compliance path (two alternative documents to follow)","No nested exceptions or conditional logic","Single technical requirement with clear background explanation","No cross-references to other legislation beyond the two external technical documents"],"plain_english_summary":"This is an **Airworthiness Directive (AD)** — a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA) that requires specific inspections or repairs on aircraft.\n\n**What it does:**\nOrders owners and operators of certain Boeing 747 aircraft to inspect a specific part called the \"inboard pylon upper link\" — a structural component that helps hold the engine to the wing.\n\n**Who it affects:**\n- All Boeing 747 models with serial numbers 1 through 616\n- Specifically those fitted with JT9D-3, JT9D-7, CF6-45, or CF6-50 engines\n\n**What must be done:**\nOperators must inspect the forward lug (a type of connector/joint) of this engine mounting link for cracks. They can follow either:\n- **Option 1:** A US Federal Aviation Administration directive (FAA AD 86-07-06, Sections A and C), OR\n- **Option 2:** Boeing's own service bulletin (747-54-2111, Revision 1)\n\n**When:**\nThe inspection must be done according to the timeline in the FAA directive (Option 1) until the aircraft is modified according to Boeing's service bulletin (Option 2).\n\n**Why it matters:**\nCracks have already been found in this part. If left unchecked, the engine could literally fall off the aircraft in flight — a catastrophic failure. This directive is designed to catch the problem before it causes an accident."},"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":false,"description":"The instrument, as written, applies inspections to all Boeing 747s line numbers 1–616 with the listed engine strut types and requires following either the FAA AD or the Boeing service bulletin until modified by the Boeing service bulletin (Applicability; Requirement; Compliance). The text does not indicate any change from an earlier stated scope within this document; it sets a clear, limited scope and links obligation termination to completion of the specified modification (Compliance)."},"complexity_factors":["Reliance on external technical documents (FAA AD 86-07-06 and Boeing Service Bulletin 747-54-2111) for the substantive inspection and modification steps (Requirement).","Applicability limited to a subset of airframes by line number and specific engine strut types, requiring operators to check serial/line records (Applicability).","Compliance structure that requires initial action per one document until modification per another document is completed (Compliance).","Safety-critical nature of the subject matter increases implementation risk and the need for specialised maintenance skills and parts (Background).","The directive text does not itself specify inspection intervals, thresholds for repair, or detailed procedures—those are in the referenced documents, increasing procedural dependence on external material (Requirement)."],"plain_english_summary":"The directive requires operators of specified Boeing 747s (line numbers 1–616 with JT9D-3/7 or CF6-45/50 struts) to inspect the inboard pylon upper link per FAA AD 86-07-06 or Boeing Service Bulletin 747-54-2111 Rev 1, and to carry out the Boeing modification to terminate recurring inspections. It was issued because cracks found in the forward lug could lead to engine separation, creating mandatory inspection, repair and cost obligations for operators and increased demand for specialist maintenance."}},"importantCases":[],"_links":{"self":"/api/acts/ad-b747-50-inboard-pylon-upper-link","history":"/api/acts/ad-b747-50-inboard-pylon-upper-link/history","analysis":"/api/acts/ad-b747-50-inboard-pylon-upper-link/analysis","conflicts":"/api/acts/ad-b747-50-inboard-pylon-upper-link/conflicts","importantCases":"/api/acts/ad-b747-50-inboard-pylon-upper-link/important-cases","documents":"/api/acts/ad-b747-50-inboard-pylon-upper-link/documents"}}