{"id":"F2006B10598","name":"AD/HU 269/27 Amdt 1 - Lower Coupling Drive Shaft - Inspection","slug":"ad-hu-269-27-amdt-1-lower-coupling-drive-shaft-inspection","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":116459,"registerId":"commonwealth-F2006B10598-current","compilationNumber":null,"startDate":"2026-04-03","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/HU 269/27 Amdt 1 - Lower Coupling Drive Shaft - 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)  Schweizer (Hughes) 269 Series Helicopters\n\n \n\nAD/HU 269/27\n\nAmdt 1\n\n\nLower Coupling Drive Shaft - Inspection 2/69\n\n \n\nApplicability: Model 269A with S/Nos. 0011 thru 0893, Model 269A-1 with S/Nos. 0001 thru 0041, Model 269A-2 with S/Nos. 0001 and 0002, Model 269B with S/Nos. 0001 thru 0359.\n\n \n\nDocument: 1. Hughes SIN No. N-55.1; or\n\n \n\n2. FAA AD 68-26-1.\n\n \n\nCompliance: For installed shafts - within 25 hours time in service after 4 November 1968.\n\n \n\nFor new replacement shafts - before installation on a helicopter after 4 November 1968.\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":true,"description":"The instrument is presented as Amendment 1 to AD/HU 269/27 (Amdt 1). The supplied text does not include the original AD’s wording, so the exact nature of any change in scope or requirements relative to the original AD cannot be determined from the material provided. The present text prescribes inspections for specified model/serial-number helicopters and delegates procedures to Hughes SIN N-55.1 or FAA AD 68-26-1 (Applicability; Document; Compliance)."},"complexity_factors":["Narrow, serial-numbered applicability (specific models and S/N ranges) which reduces breadth but requires precise fleet identification (Applicability).","Short, absolute compliance windows tied to a historical date (installed shafts within 25 hours TIS after 4 November 1968; replacements before installation after that date) which impose scheduling pressure (Compliance).","Procedural content is delegated to external documents (Hughes SIN N-55.1 or FAA AD 68-26-1), so users must obtain and interpret those materials to implement the AD (Document).","The instrument is an amendment (Amdt 1) but the supplied text does not include the original AD text, which complicates assessment of what changed (header).","No procedural detail or corrective-action steps are included in the supplied text, increasing reliance on cross-referenced material for actual work implementation (Document)."],"plain_english_summary":"What this instrument does (mechanically)\n\n- This is an airworthiness directive titled “Lower Coupling Drive Shaft - Inspection” for Schweizer (Hughes) 269 series helicopters (AD/HU 269/27 Amdt 1). (header)\n- It requires an inspection of the lower coupling drive shaft on specified 269-series helicopters. The directive points operators to existing inspection procedures in either Hughes Service Instruction No. N-55.1 or FAA AD 68-26-1 and makes compliance with one of those documents mandatory. (Document)\n- It sets two timing rules: for shafts already installed, the inspection must be done within 25 hours time in service after 4 November 1968; for new replacement shafts, the inspection must be completed before installation on a helicopter after 4 November 1968. (Compliance)\n\nWho is affected\n\n- Owners/operators of Schweizer (Hughes) 269 helicopters with the serial numbers listed in the Applicability section. The affected models and serial-number ranges are:\n  - Model 269A: S/N 0011 through 0893\n  - Model 269A-1: S/N 0001 through 0041\n  - Model 269A-2: S/N 0001 and 0002\n  - Model 269B: S/N 0001 through 0359\n  (Applicability)\n\nWhy it matters (stated purpose and practical implications)\n\n- The directive’s title and text impose a mandatory inspection regime; the instrument itself does not set out any separate explanatory rationale beyond requiring the inspection. The operative effect is to create a near-term inspection obligation for operators of the listed helicopters. (title; Compliance)\n\nWho pays, who decides, and what changes in behaviour\n\n- Who pays: Operators or owners of the listed helicopters will bear the direct costs of performing the inspections and any consequent maintenance actions, because the Compliance section makes the inspection mandatory for those machines. (Applicability; Compliance)\n- Who decides: The directive is issued under the Commonwealth of Australia (Civil Aviation Regulations 1998), Part 39 — Civil Aviation Safety Authority; it requires following an external Hughes or FAA document for the inspection procedure. The AD prescribes what must be done and delegates the technical how-to to the referenced documents. (header; Document)\n- Behaviour changes required of affected parties: schedule and carry out the mandated inspection within the stated deadline (installed shafts within 25 hours TIS after 4 November 1968; replacement shafts before installation after 4 November 1968) and follow the procedures in the named documents. This may require grounding aircraft until the inspection is completed and documented. (Compliance; Document)\n\nTrade-offs, costs, and practical risks (as grounded in the instrument)\n\n- Compliance burden: The AD imposes a short, specific time window for inspections (25 hours TIS after 4 November 1968 for installed shafts), which requires operators to track flight hours precisely and to arrange inspections quickly. (Compliance)\n- Reliance on external documents: The AD mandates use of Hughes Service Instruction N-55.1 or FAA AD 68-26-1 for the inspection procedure; the directive does not include the inspection steps itself, so effective implementation depends on access to and clarity of those referenced documents. (Document)\n- Concentration of effects: The obligations apply only to a defined set of serial-numbered helicopters, so costs fall on a concentrated group of owners/operators. Any safety or operational benefits also accrue primarily to that same group and to entities relying on their aircraft. (Applicability)\n- Opportunity cost and operational impact: Operators may have to reallocate maintenance resources and aircraft availability to meet the inspection timetable. The directive’s deadlines could force short-term changes to flight scheduling. (Compliance)\n- Implementation risk: Because the AD does not itself describe the inspection steps, differences between the two referenced documents or difficulty obtaining them could create ambiguity about compliance. (Document)\n\nWhat the instrument does not say (in the supplied text)\n\n- The supplied text does not include a descriptive rationale (for example, a statement of the specific defect or incident prompting the AD), does not list the inspection steps, and does not describe corrective action if inspection finds a problem. Instead, it refers operators to external documents for those technical details. (Document)"},"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 in specific helicopter models. It has not expanded beyond its original purpose of mandating inspection of lower coupling drive shafts."},"complexity_factors":["Very short document (approximately 200 words)","Only 4 defined applicability categories (specific helicopter models and serial number ranges)","Simple binary compliance structure (installed shafts vs new replacement shafts)","No cross-references to other legislation beyond citing source documents (Hughes SIN and FAA AD)","Single technical requirement (inspection) with clear deadline","No nested exceptions or conditional logic"],"plain_english_summary":"**What this is:** This is an **Airworthiness Directive (AD)** — a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA) that requires specific maintenance action on certain helicopters.\n\n**What it does:** It orders owners and operators of specific **Schweizer (formerly Hughes) 269 series helicopters** to inspect the **lower coupling drive shaft** — a critical component that transfers power in the helicopter's rotor system. The directive applies to particular serial numbers of Models 269A, 269A-1, 269A-2, and 269B.\n\n**Who must comply:**\n- **For shafts already installed:** Inspect within 25 hours of flight time after 4 November 1968\n- **For new replacement shafts:** Inspect *before* installing them on any helicopter after 4 November 1968\n\n**Why it matters:** Drive shaft failures in helicopters can be catastrophic. This directive addresses a known safety issue (referenced in Hughes Service Information Notice N-55.1 and a US FAA directive) to prevent mechanical failure that could lead to loss of control or crash.\n\n**Key point:** This is not optional — compliance is legally mandatory under the Civil Aviation Regulations 1998, Part 39."}},"importantCases":[],"_links":{"self":"/api/acts/ad-hu-269-27-amdt-1-lower-coupling-drive-shaft-inspection","history":"/api/acts/ad-hu-269-27-amdt-1-lower-coupling-drive-shaft-inspection/history","analysis":"/api/acts/ad-hu-269-27-amdt-1-lower-coupling-drive-shaft-inspection/analysis","conflicts":"/api/acts/ad-hu-269-27-amdt-1-lower-coupling-drive-shaft-inspection/conflicts","importantCases":"/api/acts/ad-hu-269-27-amdt-1-lower-coupling-drive-shaft-inspection/important-cases","documents":"/api/acts/ad-hu-269-27-amdt-1-lower-coupling-drive-shaft-inspection/documents"}}