{"id":"F2006B05750","name":"AD/PA-31/46 - Exhaust System - Modification","slug":"ad-pa-31-46-exhaust-system-modification","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":135591,"registerId":"commonwealth-F2006B05750-current","compilationNumber":null,"startDate":"2026-04-03","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/PA-31/46 - Exhaust System - 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)  Piper PA-31 Series Aeroplanes\n\n \n\nAD/PA-31/46 Exhaust System - Modification 6/76\n\nApplicability: Model PA-31 with S/Nos. 31P-1 to 31P-7400222, 31P-7400224 to 31P-7630004, 31P-3630006 and 31P-7630007.\n\n \n\nDocument: Piper SB No. 492.\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 \n\n \n","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"The supplied AD excerpt does not indicate any change in scope from prior material. It sets a specific, limited scope: modification of the exhaust system for the PA-31 serial numbers listed and refers to Piper SB No. 492 for the technical work. No text in the supplied document shows an expansion or narrowing of scope relative to an earlier instrument."},"complexity_factors":["Very short text with narrowly defined applicability (serial numbers explicitly listed) (Applicability)","No procedural or timing details included in the supplied excerpt (absence of compliance timeline/enforcement text)","References an external technical document (Piper SB No. 492) for implementation details (Document: Piper SB No. 492)","Legal basis and issuing authority are clearly identified (Commonwealth Civil Aviation Regulations Part 39 — CASA)"],"plain_english_summary":"What this instrument does (mechanically)\n\n- This is Airworthiness Directive AD/PA-31/46 titled \"Exhaust System - Modification\" (dated 6/76). It requires a modification to the exhaust system of certain Piper PA-31 aeroplanes. (AD/PA-31/46 Exhaust System - Modification 6/76)\n- The directive applies only to Model PA-31 aeroplanes with the serial numbers listed: 31P-1 to 31P-7400222, 31P-7400224 to 31P-7630004, 31P-3630006 and 31P-7630007. (Applicability)\n- The AD references Piper Service Bulletin No. 492 as the document that contains the modification instructions. (Document: Piper SB No. 492)\n- The AD is published in the Schedule of Airworthiness Directives under the Commonwealth Civil Aviation Regulations (Part 39 — Civil Aviation Safety Authority). (COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY)\n\nWho is affected and who decides\n\n- The set of affected parties is limited to owners/operators of the specific PA-31 serial-numbered aircraft listed in the Applicability section. (Applicability)\n- The Civil Aviation Safety Authority (CASA), under the Civil Aviation Regulations Part 39 framework, is the issuer of the Schedule of Airworthiness Directives in which this AD appears. (COMMONWEALTH ... PART 39 - 105)\n\nHow it works in practice (implementation pointers and what's not in the text)\n\n- The AD directs modification of the exhaust system by reference to Piper SB No. 492; the Service Bulletin is the detailed technical document for performing the work. (Document: Piper SB No. 492)\n- The AD text supplied does not specify a compliance time, cost allocation, enforcement mechanism, or any exemptions. Those operational details are not present in the supplied text and would normally be found in the full AD text or the referenced service bulletin. (No compliance timing/cost/enforcement text present)\n\nWho pays, incentives, compliance burden and discretion (source-grounded)\n\n- The text does not state who pays for the modification. The AD identifies the affected aircraft and the technical document to be used (Piper SB No. 492) but includes no explicit funding or reimbursement rules. (Applicability; Document: Piper SB No. 492)\n- The directive creates a compliance obligation for the aircraft identified (the obligation is implicit from the AD's presence in the Schedule), but the supplied excerpt does not set out timelines, penalties, or approval/discretion arrangements. (AD listing; absence of enforcement/ timing language)\n- Because the AD points to a manufacturer service bulletin for the modification method, practical implementation depends on the content of that service bulletin (parts required, labour, and procedural steps). Those details are external to the supplied text. (Document: Piper SB No. 492)\n\nTrade-offs and operational effects (mechanical effects, not policy judgments)\n\n- The AD narrows the regulatory action to a defined subset of aircraft by serial number, which concentrates the directive's effect on those owners/operators while leaving other PA-31 airframes outside the listed scope. (Applicability)\n- The supplied text does not quantify costs, downtime, or safety outcomes; it only establishes the requirement and the technical reference. (AD text as supplied)\n\nWhere to look next\n\n- For the exact modification steps, compliance time, parts lists, estimated labour and any acceptance/inspection criteria, consult Piper SB No. 492 and the complete AD notice as published by CASA. (Document: Piper SB No. 492; AD/PA-31/46)\n"},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, single-issue airworthiness directive from 1976 addressing a specific exhaust system modification. It has not expanded beyond its original scope of ensuring exhaust system integrity on specific Piper PA-31 aircraft."},"complexity_factors":["Very short document (approximately 150 words)","Only 1 defined term (applicability by serial number)","No cross-references to other legislation or regulations","Single, clear action required (comply with Piper SB 492)","No conditional logic, exceptions, or nested provisions","Straightforward applicability test (specific serial number ranges)"],"plain_english_summary":"**What this is:** This is an **Airworthiness Directive (AD)** — a mandatory safety order issued by the Civil Aviation Safety Authority (CASA) that requires owners or operators of specific aircraft to take action to fix a safety problem.\n\n**What it does:** This AD applies to **Piper PA-31 series aeroplanes** (twin-engine aircraft commonly used for charter, freight, and air ambulance work). It requires a **modification to the exhaust system** on specific aircraft identified by their serial numbers.\n\n**Who it affects:** Owners and operators of Piper PA-31 aircraft with serial numbers in the ranges:\n- 31P-1 to 31P-7400222\n- 31P-7400224 to 31P-7630004\n- 31P-3630006\n- 31P-7630007\n\n**What must be done:** The aircraft must be modified according to **Piper Service Bulletin No. 492** (a technical instruction document from the manufacturer). The \"6/76\" indicates this directive was issued in June 1976.\n\n**Why it matters:** Exhaust system failures can cause carbon monoxide poisoning (a deadly, odourless gas that can enter the cabin), engine power loss, or fire. This AD ensures affected aircraft are modified to prevent these hazards.\n\n**Key point:** Compliance is **mandatory** — you cannot legally fly these aircraft without completing this modification."}},"importantCases":[],"_links":{"self":"/api/acts/ad-pa-31-46-exhaust-system-modification","history":"/api/acts/ad-pa-31-46-exhaust-system-modification/history","analysis":"/api/acts/ad-pa-31-46-exhaust-system-modification/analysis","conflicts":"/api/acts/ad-pa-31-46-exhaust-system-modification/conflicts","importantCases":"/api/acts/ad-pa-31-46-exhaust-system-modification/important-cases","documents":"/api/acts/ad-pa-31-46-exhaust-system-modification/documents"}}