{"id":"F2008L02644","name":"AD/PA-31/53 - Exhaust Transition Coupling - Retirement Life - CANCELLED","slug":"ad-pa-31-53-exhaust-transition-coupling-retirement-life-cancelled","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"repealed","isInForce":false,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":74681,"registerId":"commonwealth-F2008L02644-current","compilationNumber":null,"startDate":"2026-04-02","status":"Repealed","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"Piper PA-31 Series Aeroplanes","sectionType":"division","heading":"Piper PA-31 Series Aeroplanes","content":"### Piper PA-31 Series Aeroplanes\n\n| AD/PA-31/53 | Exhaust Transition Coupling - Retirement Life | 8/2008 |\n| ----------- | --------------------------------------------- | ------ |\n\n| Requirement: | CANCELLED.                                                                                                                                                                                        |\n| ------------ | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n|              | This AD is cancelled on 31 July 2008.                                                                                                                                                             |\n| Background:  | This unique Australian AD required retirement of exhaust transition couplings after 600 hours TIS in accordance with Lycoming SB No. 395. This retirement life no longer warrants being mandated. |\n\n![](image.001.png)\n\nJames Coyne  \nDelegate of the Civil Aviation Safety Authority\n\n12 June 2008","sortOrder":0},{"sectionNumber":"AD/PA-31/53","sectionType":"part","heading":"AD/PA-31/53","content":"## AD/PA-31/53","sortOrder":1},{"sectionNumber":"Exhaust Transition Coupling - Retirement","sectionType":"part","heading":"Exhaust Transition Coupling - Retirement Life","content":"## Exhaust Transition Coupling - Retirement Life","sortOrder":2},{"sectionNumber":"8/2008","sectionType":"part","heading":"8/2008","content":"## 8/2008","sortOrder":3}],"analysis":{"kimi_summary":{"_metrics":{"model":"kimi-k2.5","source":"moonshot-batch","completionTokens":1420},"content_quality":"ok","complexity_score":1,"scope_assessment":{"changed":false,"description":"This instrument performs precisely the function stated in its title and requirement field: the cancellation of Airworthiness Directive AD/PA-31/53. It does not expand regulatory scope or introduce new requirements; it simply removes a previous mandate concerning exhaust transition couplings."},"complexity_factors":["Single, unambiguous cancellation instruction","No defined terms or interpretive provisions","No conditional logic, cross-references, or exceptions","Extremely brief - only essential information provided","Clear effective date and explicit statement of cancellation"],"plain_english_summary":"This document **cancels a previous safety rule** for specific aircraft. \n\n**What it affected:** Owners and operators of Piper PA-31 series aeroplanes (light twin-engine aircraft).\n\n**What the old rule required:** Aircraft owners had to replace \"exhaust transition couplings\" (metal joints in the engine exhaust system) after they had been used for 600 flight hours, following a manufacturer's service bulletin.\n\n**What this document does:** It removes that mandatory replacement requirement. As of 31 July 2008, owners no longer need to retire these parts at the 600-hour mark, though they must still maintain their aircraft according to other safety rules.\n\n**Why it matters:** It reduces maintenance costs and regulatory burden for operators of these aircraft, as the safety authority determined the forced retirement was no longer necessary for airworthiness."}},"importantCases":[],"_links":{"self":"/api/acts/ad-pa-31-53-exhaust-transition-coupling-retirement-life-cancelled","history":"/api/acts/ad-pa-31-53-exhaust-transition-coupling-retirement-life-cancelled/history","analysis":"/api/acts/ad-pa-31-53-exhaust-transition-coupling-retirement-life-cancelled/analysis","conflicts":"/api/acts/ad-pa-31-53-exhaust-transition-coupling-retirement-life-cancelled/conflicts","importantCases":"/api/acts/ad-pa-31-53-exhaust-transition-coupling-retirement-life-cancelled/important-cases","documents":"/api/acts/ad-pa-31-53-exhaust-transition-coupling-retirement-life-cancelled/documents"}}