{"id":"F2006B02431","name":"AD/APU/13 - Augmentation Containment Ring","slug":"ad-apu-13-augmentation-containment-ring","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":41687,"registerId":"commonwealth-F2006B02431-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/APU/13 - Augmentation Containment Ring","content":"COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 \\- 107 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n![](image.001.png)  \nAuxiliary Power Units\n\nAD/APU/13 Augmentation Containment Ring 8/97\n\nApplicability: AlliedSignal Inc., GTCP85 series auxiliary power units (APUs) incorporating a one piece cast turbine wheel, P/No 968095-xx, 3604604-xx, 3606982-xx, or 3842072-xx\n\nRequirement: Install a containment augmentation ring in accordance with either AlliedSignal Aerospace Alert Service Bulletin GTCP85-49-A6706 Revision 2 (or earlier revision) or AlliedSignal Aerospace Alert Service Bulletin GTCP85-49-A7189 Revision 2 (or earlier revision)\n\nNote 1. FAA AD 97-04-04 also refers.\n\nNote 2. This Directive supersedes AD/APU/6 Amdt1.\n\nCompliance: For flight operable APUs, within 24 months of the effective date of this directive, or for APUs that are ground operable only, within 36 months of the effective date of this directive.\n\nThis airworthiness directive becomes effective on 17 July 1997.\n\nBackground: The FAA has advised that the Hastelloy S containment shield introduced by AlliedSignal SB GTCP85-49-5700 failed to contain fragments following the rupture of a one-piece cast turbine wheel.\n\nNon-containment of high energy rotor fragments can result in penetration of the APU compartment, thereby reducing the fire protection capability of the APU and potentially causing damage to the aircraft structure.","sortOrder":0}],"analysis":{"flash_summary_failed":{"failed":true,"reason":"A positive credit balance is required for all requests, including BYOK, so fallback providers remain available. Add credits at https://vercel.com/d?to=%2F%5Bteam%5D%2F%7E%2Fai%3Fmodal%3Dtop-up to continue.","source":"analysis-cron"},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete airworthiness directive addressing a specific mechanical failure mode in specific APUs. It has not expanded beyond its original safety purpose."},"complexity_factors":["Single, specific technical requirement with clear alternative compliance paths (two acceptable service bulletins)","Limited applicability: only 4 specific part numbers and one APU series affected","Straightforward compliance timeline with simple binary distinction (flight operable vs ground operable)","No defined terms section, no cross-references to other legislation beyond a reference to FAA AD 97-04-04","Single background issue with clear causal chain (turbine rupture → shield failure → fragment escape → fire/structural risk)","Document is essentially a 1-page directive with minimal conditional logic"],"plain_english_summary":"This CASA safety order requires operators of AlliedSignal GTCP85-series APUs with the one-piece cast turbine wheel to install an augmentation containment ring because the original Hastelloy S containment shield can fail and allow high‑speed fragments to breach the APU bay, risking fire and structural damage. Flight‑operable units must be modified within 24 months and ground‑only units within 36 months of 17 July 1997, by following AlliedSignal service bulletins GTCP85‑49‑A6706 Rev 2 or GTCP85‑49‑A7189 Rev 2."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":true,"description":"This AD explicitly supersedes AD/APU/6 Amdt1 and reissues a containment requirement to install an augmentation ring on specified GTCP85 APUs, clarifying affected part numbers and setting 24‑month (flight‑operable) and 36‑month (ground‑only) compliance deadlines (see 'Applicability', 'Requirement', 'Compliance')."},"complexity_factors":["Narrow technical scope: applies only to AlliedSignal GTCP85 series APUs with specific part numbers (Applicability)","Dependence on external manufacturer documents (AlliedSignal Alert Service Bulletins Rev 2 or earlier) to define the required modification (Requirement)","Differing compliance deadlines depending on APU operability (24 vs 36 months) increases scheduling complexity (Compliance)","Supersedes a prior AD (AD/APU/6 Amdt1), requiring operators to reconcile previous compliance actions","Safety‑critical subject matter (risk of high‑energy fragment penetration) imposes strict enforcement and potential downtime","Cross-reference to FAA AD introduces external regulatory alignment considerations (Note 1)"],"plain_english_summary":"This airworthiness directive requires operators of AlliedSignal GTCP85-series APUs with the listed part numbers to install an augmentation containment ring in accordance with the AlliedSignal Alert Service Bulletins (Requirement). CASA requires installation within 24 months for flight‑operable APUs and 36 months for ground‑only APUs (Compliance).\n\nOperators pay for parts, labour and downtime; CASA enforces the directive and accepts compliance by following the listed service bulletins. The directive responds to FAA advice that a Hastelloy S shield failed to contain one‑piece cast turbine wheel fragments (Background)."}},"importantCases":[],"_links":{"self":"/api/acts/ad-apu-13-augmentation-containment-ring","history":"/api/acts/ad-apu-13-augmentation-containment-ring/history","analysis":"/api/acts/ad-apu-13-augmentation-containment-ring/analysis","conflicts":"/api/acts/ad-apu-13-augmentation-containment-ring/conflicts","importantCases":"/api/acts/ad-apu-13-augmentation-containment-ring/important-cases","documents":"/api/acts/ad-apu-13-augmentation-containment-ring/documents"}}