{"id":"F2006B02740","name":"AD/B727/4 - Main Landing Gear Manual Extension Torque Tube - Modification","slug":"ad-b727-4-main-landing-gear-manual-extension-torque-tube-modification","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":42082,"registerId":"commonwealth-F2006B02740-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/B727/4 - Main Landing Gear Manual Extension Torque Tube - 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 727 Series Aeroplanes\n\n \n\nAD/B727/4 Main Landing Gear Manual Extension\n\nTorque Tube - Modification\n\nApplicability: All models with S/Nos. specified in SB 32-54. Document:  Boeing SB 32-54.\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\n \n\n \n\n\n9/65\n","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The AD itself does not indicate any change to scope from an earlier instrument. It applies to all models with serial numbers specified in Boeing SB 32-54 (\"Applicability\") and requires compliance immediately (\"Compliance: Forthwith\"). There is no text in this AD that expands or narrows that applicability compared to a prior scope; any detailed scope determination depends on the serial numbers listed in Boeing SB 32-54."},"complexity_factors":["Narrow, well-defined scope limited to Boeing 727 serial numbers listed in an external document (Boeing SB 32-54) which requires consulting that bulletin to identify affected aircraft (see \"Applicability\" and \"Document: Boeing SB 32-54\").","Mandatory immediate compliance language (\"Forthwith\") leaves little regulatory flexibility and creates operational scheduling pressure (see \"Compliance: Forthwith\").","The AD delegates technical detail to an external service bulletin rather than reproducing modification steps, so implementation depends on an external document (see \"Document: Boeing SB 32-54\").","Limited text in the AD about alternative compliance methods, cost, or exemptions increases practical complexity for operators who may need to liaise with CASA or seek approvals.","Potential logistical complexity (sourcing parts, arranging maintenance slots) is implied by the requirement to perform a mechanical modification, though the AD does not quantify those burdens."],"plain_english_summary":"### What this directive does, in plain terms\n\nThis Airworthiness Directive (AD) orders a modification to the main landing gear manual extension torque tube on certain Boeing 727 aeroplanes. The AD requires work to be carried out according to the Boeing Service Bulletin identified in the document (Boeing SB 32-54) (see \"Document: Boeing SB 32-54\").\n\nMechanically: the AD changes the configuration or parts of the torque tube used for manual extension of the main landing gear by requiring the modification set out in the Boeing service bulletin.\n\nWho it affects\n\n- Operators and owners of Boeing 727 aircraft whose serial numbers are listed in Boeing SB 32-54 (see \"Applicability: All models with S/Nos. specified in SB 32-54\").\n- Maintenance organisations and suppliers that perform or supply parts for the modification specified in Boeing SB 32-54.\n\nHow it works and how quickly it must be done\n\n- The AD makes compliance mandatory and requires the modification to be carried out immediately: the compliance instruction is \"Forthwith\" (see \"Compliance: Forthwith\").\n- The AD points operators to Boeing SB 32-54 for the technical instructions and the list of affected serial numbers (see \"Document: Boeing SB 32-54\" and \"Applicability\").\n\nWho pays, who decides, and how behaviour changes\n\n- Operators/owners pay for the modification work, including labour, parts and any aircraft downtime needed to complete the SB instructions (the AD requires compliance with Boeing SB 32-54). The AD itself does not allocate funding or exemptions.\n- The Civil Aviation Safety Authority (CASA) issues the AD; compliance is mandatory for affected aircraft. The technical steps and parts are those given in Boeing SB 32-54.\n- Behaviourally, operators must schedule and complete the modification before further operation (or as soon as practicable, consistent with \"Forthwith\"). Maintenance organisations must follow the Boeing service bulletin instructions.\n\nCosts, incentives and trade-offs (mechanically stated)\n\n- Direct costs: parts, labour and aircraft downtime to perform the modification per Boeing SB 32-54.\n- Administrative/compliance burden: identifying affected aircraft requires consulting Boeing SB 32-54 for serial numbers; documenting completion for regulatory compliance.\n- Implementation risk and discretion: the AD gives little operational discretion because it requires compliance \"Forthwith\"; the AD itself does not set alternative compliance methods or timelines, so operators must follow the SB or seek CASA-approved alternative means of compliance.\n\nDocument references in the AD\n\n- Applicability: \"All models with S/Nos. specified in SB 32-54.\" (Applicability)\n- Technical instructions: \"Document: Boeing SB 32-54.\" (Document)\n- Timing: \"Compliance: Forthwith.\" (Compliance)\n"},"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 component of a specific aircraft type. It has not expanded beyond its original purpose of mandating a safety modification."},"complexity_factors":["Extremely short document (approximately 150 words)","No defined terms section — relies entirely on external Boeing document (SB 32-54)","No conditional logic or exceptions","Single, unambiguous compliance requirement ('forthwith')","No cross-references to other legislation beyond the enabling Civil Aviation Regulations 1998","Minimal structural elements (applicability, document reference, compliance date only)"],"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:**\n- Requires a specific modification to the **main landing gear manual extension torque tube** on Boeing 727 aircraft.\n- The torque tube is a mechanical component that helps pilots manually extend the landing gear if the normal hydraulic system fails.\n\n**Who it affects:**\n- Owners and operators of **Boeing 727 series aeroplanes** with specific serial numbers listed in Boeing Service Bulletin 32-54.\n\n**What must be done:**\n- The modification described in **Boeing Service Bulletin 32-54** must be carried out **\"forthwith\"** (immediately, without delay).\n\n**Why it matters:**\n- This directive addresses a safety-critical system. If the manual landing gear extension system fails, pilots may be unable to lower the wheels in an emergency, potentially leading to a crash landing. The modification fixes a known defect in the torque tube design."}},"importantCases":[],"_links":{"self":"/api/acts/ad-b727-4-main-landing-gear-manual-extension-torque-tube-modification","history":"/api/acts/ad-b727-4-main-landing-gear-manual-extension-torque-tube-modification/history","analysis":"/api/acts/ad-b727-4-main-landing-gear-manual-extension-torque-tube-modification/analysis","conflicts":"/api/acts/ad-b727-4-main-landing-gear-manual-extension-torque-tube-modification/conflicts","importantCases":"/api/acts/ad-b727-4-main-landing-gear-manual-extension-torque-tube-modification/important-cases","documents":"/api/acts/ad-b727-4-main-landing-gear-manual-extension-torque-tube-modification/documents"}}