{"id":"F2006B02429","name":"AD/APU/11 - TSCP700 HPT Disc","slug":"ad-apu-11-tscp700-hpt-disc","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":41684,"registerId":"commonwealth-F2006B02429-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/APU/11 - TSCP700 HPT Disc","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/11 TSCP700 HPT Disc 1/97\n\nApplicability: AlliedSignals TSCP700 Series Auxiliary Power Units, incorporating a High Pressure Turbine (HPT) disc identified with a serial number listed in AlliedSignals Service Bulletin TSCP700-49-A7168.\n\n \n\nRequirement: Remove from service affected HPT discs as identified in AlliedSignals Service Bulletin TSCP700-49-A7168.\n\n \n\nNote: FAA AD 96-18-17 also refers.\n\n \n\nCompliance: Effective 2 January 1997; prior to accumulating 7500 cycles since new or no later than 2 January 2000, whichever occurs first.\n\n \n\nBackground: The manufacturer has advised that some HPT discs have been manufactured from nonconforming material which has required a reduction in service life.\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":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, time-bound safety directive targeting a specific manufacturing defect. It has not expanded beyond its original purpose of grounding faulty HPT discs."},"complexity_factors":["Single, specific mechanical component targeted (HPT disc)","Only one substantive requirement: remove affected parts","Clear compliance deadline with simple 'whichever occurs first' condition","Minimal cross-referencing (one FAA AD and one manufacturer service bulletin)","No defined terms section, no nested exceptions, no conditional logic beyond the compliance date formula","Document is essentially a one-page safety notice"],"plain_english_summary":"**What this is:** This is an Airworthiness Directive (AD) — a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA).\n\n**What it does:** It orders the removal from service of specific high-pressure turbine (HPT) discs used in AlliedSignal TSCP700 auxiliary power units (APUs). These are small jet engines that provide power to aircraft when the main engines are off.\n\n**Who it affects:** Anyone operating aircraft with these specific APUs — the discs in question have serial numbers listed in a manufacturer service bulletin (TSCP700-49-A7168).\n\n**Why it matters:** Some of these discs were made from faulty material, making them wear out faster than designed. Flying with them risks engine failure. The directive gives operators a deadline: remove the disc before it hits 7,500 flight cycles **or** by 2 January 2000, whichever comes first.\n\n**Key deadline:** The rule took effect on 2 January 1997, giving operators roughly three years maximum to comply."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"Scope remains limited to the HPT discs identified by serial number in the manufacturer's service bulletin; the instrument shortens allowable service life and mandates removal rather than broadening affected equipment or operators."},"complexity_factors":["Narrow applicability tied to serial numbers listed in AlliedSignals Service Bulletin TSCP700-49-A7168 (Applicability)","Fixed dual compliance trigger: removal before 7,500 cycles since new or by 2 January 2000, whichever occurs first (Compliance)","Obligation on operators to identify affected units, track cycles, remove and replace components — direct compliance cost and logistical burden (Requirement; Compliance)","Dependence on the manufacturer's service bulletin for identification of affected parts and on manufacturer information about material nonconformance (Requirement; Background)","Cross-reference to FAA AD 96-18-17 may require coordination or harmonisation for internationally operated aircraft (Note)","Effective date (2 January 1997) creates an immediate compliance window for some operators (Compliance)"],"plain_english_summary":"This airworthiness directive requires operators to remove from service specific AlliedSignals TSCP700 high‑pressure turbine (HPT) discs identified by serial number in AlliedSignals Service Bulletin TSCP700‑49‑A7168 (Requirement; Applicability). Removal must occur before a disc reaches 7,500 cycles since new or by 2 January 2000, whichever is earlier (Compliance). Operators bear the cost and administrative burden; CASA issued the AD after the manufacturer advised some discs were made from non‑conforming material (Background; Note)."}},"importantCases":[],"_links":{"self":"/api/acts/ad-apu-11-tscp700-hpt-disc","history":"/api/acts/ad-apu-11-tscp700-hpt-disc/history","analysis":"/api/acts/ad-apu-11-tscp700-hpt-disc/analysis","conflicts":"/api/acts/ad-apu-11-tscp700-hpt-disc/conflicts","importantCases":"/api/acts/ad-apu-11-tscp700-hpt-disc/important-cases","documents":"/api/acts/ad-apu-11-tscp700-hpt-disc/documents"}}