{"id":"F2006B02758","name":"AD/B727/56 - Main Landing Gear Shock Strut Outer Cylinder - Inspection","slug":"ad-b727-56-main-landing-gear-shock-strut-outer-cylinder-inspection","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":42100,"registerId":"commonwealth-F2006B02758-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/B727/56 - Main Landing Gear Shock Strut Outer Cylinder - Inspection","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 727 Series Aeroplanes\n\n \n\nAD/B727/56 Main Landing Gear Shock Strut Outer Cylinder - Inspection\n\n\n4/68\n\n \n\nApplicability: All models.\n\n \n\nRequirement: Inspect for cracking, all chrome plated main landing gear outer cylinder aft trunnion extensions which have been overhauled in a manner other than specifically described by Boeing 727 Overhaul Manual Section 32/12/1.\n\n \n\nCompliance: Forthwith.\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\n \n","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"Based solely on the supplied text, there is no indication that the directive’s scope has been changed from its original formulation. The document states applicability (all Boeing 727 models), a specific inspection requirement tied to a particular overhaul-history condition, and an immediate compliance timeframe. No amendments, narrowed or expanded provisions, or later modifications are shown in the excerpt provided."},"complexity_factors":["Narrow technical target: inspection limited to a specific component (chrome-plated main landing gear outer cylinder aft trunnion extensions). (Requirement)","External reference: compliance determination depends on whether overhaul was performed per Boeing 727 Overhaul Manual Section 32/12/1, requiring access to and interpretation of that manual and overhaul records. (Requirement)","Urgent timing: compliance required \"forthwith\", increasing logistical pressure on operators to identify affected parts quickly. (Compliance)","Record-verification burden: need to trace overhaul history for parts across the fleet to determine applicability. (Requirement)","Absence of specified corrective action in the text: the directive mandates inspection but does not set out follow-on repairs or acceptance criteria in this excerpt, leaving further steps to other maintenance rules or guidance. (Requirement)"],"plain_english_summary":"This directive requires immediate (\"forthwith\") physical inspections for cracking of chrome‑plated main‑landing‑gear outer‑cylinder aft trunnion extensions on all Boeing 727 models, but only where those parts were overhauled other than as described in Boeing 727 Overhaul Manual Section 32/12/1. \n\nIt obliges aircraft operators/owners to identify affected parts and arrange inspections; maintenance providers bear labour/materials, with operators ultimately responsible for costs. The AD creates an urgent operational duty and incentives to follow the cited overhaul procedure."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, targeted safety directive addressing a specific technical defect in a specific aircraft type. It has not expanded beyond its original purpose of ensuring airworthiness of Boeing 727 landing gear components."},"complexity_factors":["Extremely short document (under 150 words)","Only 1 defined term implicitly referenced ('overhaul' understood by industry context)","No cross-references to other legislation or regulations beyond the enabling authority (Civil Aviation Regulations 1998, Part 39)","Single, unambiguous requirement with one clear condition (overhaul method)","No nested exceptions or conditional logic — straightforward applicability and compliance trigger"],"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 727 aircraft** to immediately inspect a specific part of the main landing gear — the chrome-plated outer cylinder at the rear attachment point (the \"aft trunnion extension\") — but **only** if that part was overhauled using a method different from Boeing's official instructions.\n\n**Who it affects:**\nAnyone who owns, operates, or maintains Boeing 727 series aircraft in Australia.\n\n**Why it matters:**\nCracks in landing gear components can lead to catastrophic failure during takeoff or landing. This directive targets a specific risk: parts that were serviced \"off-book\" (not following Boeing's prescribed overhaul manual) may have hidden defects. The \"forthwith\" compliance means **do it immediately** — no grace period.\n\n**Key takeaway:** If your Boeing 727's main landing gear was overhauled using non-standard methods, you must inspect it now for cracks."}},"importantCases":[],"_links":{"self":"/api/acts/ad-b727-56-main-landing-gear-shock-strut-outer-cylinder-inspection","history":"/api/acts/ad-b727-56-main-landing-gear-shock-strut-outer-cylinder-inspection/history","analysis":"/api/acts/ad-b727-56-main-landing-gear-shock-strut-outer-cylinder-inspection/analysis","conflicts":"/api/acts/ad-b727-56-main-landing-gear-shock-strut-outer-cylinder-inspection/conflicts","importantCases":"/api/acts/ad-b727-56-main-landing-gear-shock-strut-outer-cylinder-inspection/important-cases","documents":"/api/acts/ad-b727-56-main-landing-gear-shock-strut-outer-cylinder-inspection/documents"}}