{"id":"F2006B02430","name":"AD/APU/12 - Compressor Wheel","slug":"ad-apu-12-compressor-wheel","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":41686,"registerId":"commonwealth-F2006B02430-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/APU/12 - Compressor Wheel","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 - 107 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n \n\n![](image.001.png)  Auxiliary Power Units\n\n \n\nAD/APU/12 Compressor Wheel 8/97\n\nApplicability: Sundstrand Aerospace T-62T-40C series Auxiliary Power Units incorporating Compressor Wheel, P/No 162690-1, 165111-1 or 167200-1\n\n \n\nRequirement: Replace affected compressor wheels in accordance with Sundstrand Aerospace Service Bulletin T-62T-49-120 Revision 2 dated 5 November 1996.\n\n \n\nNote: FAA AD 96-25-12 also refers.\n\n \n\nCompliance: As detailed in the requirement document.\n\n \n\nThis airworthiness directive becomes effective on 17 July 1997.\n\n \n\nBackground: The manufacturer has advised three compressor wheel failures have occurred as a result of fatigue cracks propagating from screw holes on the backface of the compressor wheel.\n\n \n\nCompressor wheel rupture could result in an uncontained APU failure and damage to an aircraft.\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 discrete safety directive addressing a specific mechanical failure mode. It has not expanded beyond its original purpose of mandating replacement of faulty compressor wheels."},"complexity_factors":["Single, specific mechanical component targeted (compressor wheel)","Only three part numbers affected","One clear action required (replacement per service bulletin)","No nested conditions, exceptions, or alternative compliance methods","Cross-reference to only one external document (FAA AD) and one service bulletin","No defined terms section — uses standard aviation terminology"],"plain_english_summary":"This CASA Airworthiness Directive mandates replacing certain compressor wheels in Sundstrand T-62T-40C series APUs (P/Ns 162690-1, 165111-1, 167200-1) because three have failed from metal fatigue at screw holes. \n\nIf a wheel ruptures it can produce uncontained debris that could damage the aircraft or injure people; operators must follow the manufacturer's service bulletin to swap the wheels by the bulletin’s compliance deadline."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"No. The directive targets the identified Sundstrand T-62T-40C compressor wheels and requires replacement per the cited service bulletin; it does not expand or narrow the set of affected parts beyond those listed, aside from referencing a related FAA AD."},"complexity_factors":["Narrow technical applicability: only three specific compressor wheel part numbers affected.","Single mandated remedial action (replacement) reduces procedural complexity.","Compliance detail outsourced to manufacturer's Service Bulletin (external document dependency).","Cross-reference to FAA AD increases cross-jurisdictional traceability requirements.","Safety-critical nature raises enforcement and timing sensitivity despite simple action.","Potential operational impacts: parts availability, scheduling downtime and labour for operators.","Directive gives limited internal detail on compliance deadlines (refers to requirement document)."],"plain_english_summary":"Requires replacement of specified Sundstrand T-62T-40C APU compressor wheels (P/No 162690-1, 165111-1, 167200-1) in accordance with Sundstrand Service Bulletin T-62T-49-120 Rev 2. CASA enforces the directive; aircraft operators (owners) must arrange and pay for the replacements and follow the service bulletin's compliance steps, because the manufacturer reported three failures from fatigue cracks at screw holes that could cause uncontained APU rupture and aircraft damage."}},"importantCases":[],"_links":{"self":"/api/acts/ad-apu-12-compressor-wheel","history":"/api/acts/ad-apu-12-compressor-wheel/history","analysis":"/api/acts/ad-apu-12-compressor-wheel/analysis","conflicts":"/api/acts/ad-apu-12-compressor-wheel/conflicts","importantCases":"/api/acts/ad-apu-12-compressor-wheel/important-cases","documents":"/api/acts/ad-apu-12-compressor-wheel/documents"}}