{"id":"F2006B10605","name":"AD/HU 269/39 Amdt 1 - Engine Exhaust System - Inspection","slug":"ad-hu-269-39-amdt-1-engine-exhaust-system-inspection","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":116473,"registerId":"commonwealth-F2006B10605-current","compilationNumber":null,"startDate":"2026-04-03","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/HU 269/39 Amdt 1 - Engine Exhaust System - 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 269/39\n\nAmdt 1\n\n\nEngine Exhaust System - Inspection 2/72\n\n \n\nApplicability: Models 269A with S/Nos. 0011 to 0314, 269A-1 with S/Nos. 0004 to 0041, 269B with S/Nos. 0001 and subsequent, 269C with S/Nos. 0001 and subsequent equipped with 269A4201 or 269A4869 exhaust cabin heater installation.\n\n \n\nDocument: Hughes SIN No. N-88.1.\n\n \n\nCompliance: Within 50 hours time in service after 29 October 1971 and thereafter at intervals not exceeding 100 hours time in service.\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":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a straightforward amendment (Amdt 1) to an existing Airworthiness Directive. It maintains the original narrow scope of requiring exhaust system inspections on specific helicopter models. There is no evidence of scope creep; it remains tightly focused on aviation safety for a defined fleet subset."},"complexity_factors":["Single, specific technical requirement (exhaust inspection)","Limited applicability (4 specific model/serial number combinations plus specific part numbers)","Simple compliance timeline (initial 50 hours, then recurring 100 hours)","No defined terms section","No cross-references to other legislation beyond the source document (Hughes SIN)","No conditional logic or exceptions","Extremely short document (approximately 150 words of substantive content)"],"plain_english_summary":"This is an **Airworthiness Directive (AD)** — essentially a mandatory safety notice issued by Australia's Civil Aviation Safety Authority (CASA) for specific helicopters.\n\n**What it does:**\nOrders owners and operators of certain Schweizer (formerly Hughes) 269 series helicopters to inspect the engine exhaust system at regular intervals. This is to check for cracks, corrosion, or other damage that could lead to dangerous situations like carbon monoxide leaking into the cabin or exhaust system failure.\n\n**Who it affects:**\nOwners and operators of specific Schweizer/Hughes 269 helicopter models with particular serial numbers and a specific type of exhaust cabin heater installed (part numbers 269A4201 or 269A4869).\n\n**Why it matters:**\nExhaust system failures in helicopters can be catastrophic — they can cause carbon monoxide poisoning of the crew or engine fires. This directive ensures regular checks catch problems before they become deadly.\n\n**What must be done:**\n- **First inspection:** Within 50 hours of flying time after 29 October 1971\n- **Ongoing inspections:** Every 100 hours of flying time thereafter\n\n**Where the instructions come from:**\nThe actual inspection procedure is detailed in Hughes Service Information Notice (SIN) No. N-88.1 — this AD just makes compliance with that document legally mandatory."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The supplied text is the amended AD (Amdt 1) but does not include the original AD wording or prior scope for direct comparison. On the basis of the material provided, the AD prescribes inspections for the listed serial-numbered models with the two specified heater installations and sets the compliance intervals; no change of scope from an earlier instrument can be identified from this text alone."},"complexity_factors":["Narrow technical scope limited to specific models, serial-number ranges and two heater-installation part references (Applicability).","Dependence on an external manufacturer document (Hughes SIN No. N-88.1) for inspection content (Document).","Time-based compliance schedule with an initial and recurring interval (initial within 50 hours after 29 Oct 1971; then every 100 hours) requires record-keeping and flight-hour tracking (Compliance).","Potential need for qualified maintenance personnel, parts or tooling to carry out whatever the SIN prescribes (implicit from reliance on manufacturer procedure).","Labelled as an amendment (Amdt 1) but the provided text does not include the original AD text for comparison, limiting interpretive clarity."],"plain_english_summary":"This AD mandates recurring inspections of the engine exhaust/heater installation on a narrow set of Schweizer (Hughes) 269-series helicopters equipped with the 269A4201 or 269A4869 heater, using Hughes Service Instruction Note N‑88.1.  \n\nInitial inspection is required within 50 flight hours after 29 Oct 1971 and then every 100 hours; operators bear inspection, repair and downtime costs and must schedule qualified maintenance to comply."}},"importantCases":[],"_links":{"self":"/api/acts/ad-hu-269-39-amdt-1-engine-exhaust-system-inspection","history":"/api/acts/ad-hu-269-39-amdt-1-engine-exhaust-system-inspection/history","analysis":"/api/acts/ad-hu-269-39-amdt-1-engine-exhaust-system-inspection/analysis","conflicts":"/api/acts/ad-hu-269-39-amdt-1-engine-exhaust-system-inspection/conflicts","importantCases":"/api/acts/ad-hu-269-39-amdt-1-engine-exhaust-system-inspection/important-cases","documents":"/api/acts/ad-hu-269-39-amdt-1-engine-exhaust-system-inspection/documents"}}