{"id":"F2006B05742","name":"AD/PA-31/38 - Heater Solenoid Shut-Off Valve - Modification","slug":"ad-pa-31-38-heater-solenoid-shut-off-valve-modification","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"repealed","isInForce":false,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":135565,"registerId":"commonwealth-F2006B05742-current","compilationNumber":null,"startDate":"2026-04-03","status":"Repealed","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/PA-31/38 - Heater Solenoid Shut-Off Valve - 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-31/38 Heater Solenoid Shut-Off Valve - Modification 12/75\n\nApplicability: Models PA-31 and PA-31-300 with S/Nos. 31-2 to 31-103.\n\n \n\nRequirement: Install shroud assembly Piper P/N 43493 with associated cover, over- board drain tube, sealing grommets and clamp, over heater solenoid shut-off valve P/N 756513 in accordance with Piper installation drawing No. 41923 and Parts Catalogue No.\n\n753703-Fig. 38.\n\n \n\nCompliance: Within 100 hours time in service after 31 December 1975.\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":{"kimi_summary":{"_metrics":{"model":"kimi-k2.5","source":"moonshot-batch","completionTokens":2275},"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This appears to be the original 1975 directive. The scope remains tightly focused on the specific heater valve modification for the designated aircraft models and has not expanded beyond this original safety requirement."},"complexity_factors":["Single specific technical requirement with no exceptions or conditional logic","Narrow applicability limited to specific aircraft models and serial number range","No cross-references to other legislative provisions within the operative text","Simple compliance calculation based on flight hours after a fixed date"],"plain_english_summary":"**What this does:** This safety directive mandates a specific modification on certain Piper Navajo aircraft to prevent fire hazards. Owners must install a protective shroud assembly (Piper part 43493) with a drain tube over the heater fuel shut-off valve.\n\n**Who it affects:** Owners and operators of Piper PA-31 and PA-31-300 aeroplanes with serial numbers 31-2 through 31-103.\n\n**What you must do:** Install the shroud, cover, over-board drain tube, sealing grommets and clamp over the heater solenoid shut-off valve (part 756513), following Piper installation drawing 41923 and the parts catalogue.\n\n**When:** Within 100 hours of flight time after 31 December 1975.\n\n**Why it matters:** This modification protects against fuel leaks from the heater valve. The shroud contains any leaking fuel, and the drain tube directs it outside the aircraft rather than allowing it to pool near hot components or inside the cabin, reducing the risk of fire."}},"importantCases":[],"_links":{"self":"/api/acts/ad-pa-31-38-heater-solenoid-shut-off-valve-modification","history":"/api/acts/ad-pa-31-38-heater-solenoid-shut-off-valve-modification/history","analysis":"/api/acts/ad-pa-31-38-heater-solenoid-shut-off-valve-modification/analysis","conflicts":"/api/acts/ad-pa-31-38-heater-solenoid-shut-off-valve-modification/conflicts","importantCases":"/api/acts/ad-pa-31-38-heater-solenoid-shut-off-valve-modification/important-cases","documents":"/api/acts/ad-pa-31-38-heater-solenoid-shut-off-valve-modification/documents"}}