{"id":"F2006B05361","name":"AD/P68/35 - LH and RH Muffler Assemblies","slug":"ad-p68-35-lh-and-rh-muffler-assemblies","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":45913,"registerId":"commonwealth-F2006B05361-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/P68/35 - LH and RH Muffler Assemblies","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)  Partenavia P68 Series Aeroplanes\n\n \n\nAD/P68/35 LH and RH Muffler Assemblies 6/91\n\nApplicability: All models excluding the ‘TC’ series.\n\n \n\nRequirement: Action in accordance with the Technical Requirements of RAI AD No 91-125/P68- 42.\n\n \n\nNote: Partenavia Service Bulletin No 83 refers.\n\n \n\nCompliance: In accordance with the Requirement Document with revised effective date 30 June 1991.\n\n \n\nBackground:  Due to the possibility of carbon monoxide entering the aircraft cabin through the heating system a repetitive inspection of the muffler assemblies has been introduced.\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":false,"description":"The instrument's stated purpose is to introduce repetitive inspection of the LH and RH muffler assemblies to address the risk of carbon monoxide entering the cabin (Background). The AD applies to all P68 models except the 'TC' series (Applicability) and requires operators to follow the technical instructions in RAI AD No 91-125/P68-42 (Requirement). Nothing in the text indicates a change of scope from that objective; the AD directs compliance to the referenced technical requirement with a revised effective date (Compliance)."},"complexity_factors":["Relies on external technical documents (RAI AD No 91-125/P68-42 and Partenavia Service Bulletin No 83) for the operative technical detail rather than containing full procedures in the AD itself (Requirement; Note).","Inspection regime described as \"repetitive\" but the AD text does not specify intervals or acceptance criteria — those are in the referenced documents (Background; Requirement).","Applicability carve-out (excludes ‘TC’ series) requires operators to confirm model classification before applying the AD (Applicability).","Compliance depends on a revised effective date (30 June 1991), which matters for retrospective scheduling and record-keeping (Compliance).","Enforcement and legal obligation are imposed by the CASA AD but technical compliance rests with another authority’s AD (RAI), introducing coordination/interpretation needs (Requirement).","Operational impact (aircraft downtime and maintenance scheduling) is recurring rather than one-off, increasing administrative and cost burden over time (Background)."],"plain_english_summary":"What this instrument does (mechanics)\n\n- It requires operators of Partenavia P68 series aeroplanes (all models except the ‘TC’ series) to carry out inspections and any associated actions set out in another technical directive: RAI AD No 91-125/P68-42 (Requirement).  The AD points operators to Partenavia Service Bulletin No 83 for reference (Note).  The stated compliance regime is to follow the Requirement Document and the AD gives a revised effective date of 30 June 1991 (Compliance).\n\nWhy it was introduced (official rationale)\n\n- The AD says the inspections are required because of the possibility that carbon monoxide could enter the cabin through the heating system; to address that risk a repetitive inspection of the left-hand and right-hand muffler assemblies has been introduced (Background).\n\nWho it affects, who decides, and who pays\n\n- Who it affects: owners and operators of Partenavia P68 aeroplanes except those in the ‘TC’ series (Applicability).\n- Who decides enforcement and legal obligation: the Civil Aviation Safety Authority (CASA) through this Airworthiness Directive and by reference to the Technical Requirements in RAI AD No 91-125/P68-42 (Requirement).\n- Who pays and bears the burden: aircraft owners/operators pay for the inspections, any maintenance or replacement work identified by those inspections, and any aircraft downtime required to comply (Requirement; Note; Compliance).\n\nWhat behaviour changes for operators\n\n- Operators must obtain and follow the technical inspection and corrective-action instructions contained in RAI AD No 91-125/P68-42 and may consult Partenavia Service Bulletin No 83 for details (Requirement; Note).  The inspections are described as repetitive, so they recur at whatever intervals the Requirement document specifies (Background; Requirement).  Compliance must be effected from the revised effective date of 30 June 1991 (Compliance).\n\nPractical trade-offs, costs and implementation points to note\n\n- The AD itself does not specify inspection intervals, acceptance criteria, or required corrective work: those technical details sit in the referenced RAI AD and the Service Bulletin. That means operators must obtain and follow external documents to know the exact technical steps and timing (Requirement; Note).\n- Direct costs to operators are the time and money for repetitive inspections, any repairs or muffler replacements found necessary, and any aircraft grounding or downtime while work is done (Requirement; Background).\n- The AD increases demand for maintenance activity specific to these mufflers; independent maintenance providers can perform the work if they follow the referenced technical requirements and the Service Bulletin (Requirement; Note).\n- Implementation risk and compliance burden include ensuring the correct model classification (excluding ‘TC’ series), obtaining the referenced technical documents, and scheduling repeated inspections into operational maintenance programs (Applicability; Requirement; Note).\n\nConcentrated benefits and diffuse costs\n\n- The principal (concentrated) beneficiary is aircraft occupants: the stated aim is to reduce the risk of carbon monoxide entering the cabin by inspecting mufflers (Background). The costs (inspection and maintenance) are borne by the dispersed group of affected aircraft owners and operators (Applicability; Requirement).\n\nSources in the instrument\n\n- Applicability: \"All models excluding the ‘TC’ series.\" (Applicability)\n- Requirement: \"Action in accordance with the Technical Requirements of RAI AD No 91-125/P68-42.\" (Requirement)\n- Note: \"Partenavia Service Bulletin No 83 refers.\" (Note)\n- Compliance: \"In accordance with the Requirement Document with revised effective date 30 June 1991.\" (Compliance)\n- Background: description of carbon monoxide risk and introduction of repetitive inspection (Background)\n\nSummary statement\n\n- Mechanically, this AD mandates that applicable P68 aircraft be inspected and any required corrective actions taken as specified in RAI AD No 91-125/P68-42 (with Service Bulletin No 83 as a reference). It imposes a recurring inspection obligation (repetitive) to address a stated risk of carbon monoxide entering the cabin. Operators must acquire and follow the referenced technical documents and bear the associated inspection and maintenance costs (Requirement; Note; Background; Compliance)."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, targeted safety directive addressing a specific mechanical defect in a specific aircraft type. It has not expanded beyond its original purpose of preventing carbon monoxide poisoning through muffler inspection."},"complexity_factors":["Very short document (approximately 150 words)","Only 1 defined applicability exclusion ('TC' series)","Single cross-reference to external technical document (RAI AD No 91-125/P68-42)","No nested conditions or exceptions","Straightforward compliance deadline","Minimal legislative machinery — essentially a notice adopting an overseas directive"],"plain_english_summary":"This is an **Airworthiness Directive (AD)** — essentially a mandatory safety order — issued by Australia's Civil Aviation Safety Authority (CASA) for certain Partenavia P68 aircraft.\n\n**What it does:**\n- Requires owners and operators of Partenavia P68 aeroplanes (except the 'TC' series) to conduct **repetitive inspections of the left-hand and right-hand muffler assemblies** (parts of the exhaust system).\n\n**Why it matters:**\n- There's a risk of **carbon monoxide** (a deadly, odourless gas) leaking into the aircraft cabin through the heating system. Faulty or cracked mufflers can allow exhaust gases to contaminate the cabin air.\n\n**What must happen:**\n- Aircraft operators must follow the technical requirements set out in **RAI AD No 91-125/P68-42** (an Italian aviation safety directive that CASA has adopted).\n- They must also consult **Partenavia Service Bulletin No 83** for guidance.\n- The inspections must be done by **30 June 1991** (the revised effective date).\n\n**Who it affects:**\n- Owners, operators, and maintenance organisations responsible for Partenavia P68 series aircraft registered in Australia."}},"importantCases":[],"_links":{"self":"/api/acts/ad-p68-35-lh-and-rh-muffler-assemblies","history":"/api/acts/ad-p68-35-lh-and-rh-muffler-assemblies/history","analysis":"/api/acts/ad-p68-35-lh-and-rh-muffler-assemblies/analysis","conflicts":"/api/acts/ad-p68-35-lh-and-rh-muffler-assemblies/conflicts","importantCases":"/api/acts/ad-p68-35-lh-and-rh-muffler-assemblies/important-cases","documents":"/api/acts/ad-p68-35-lh-and-rh-muffler-assemblies/documents"}}