{"id":"F2006B07414","name":"AD/TFE 731/8 - Second Stage Turbine Disc Inspection","slug":"ad-tfe-731-8-second-stage-turbine-disc-inspection","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":49653,"registerId":"commonwealth-F2006B07414-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/TFE 731/8 - Second Stage Turbine Disc Inspection","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 - 106 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n \n\n![](image.001.png)  AlliedSignal (Garrett/AiResearch) Turbine Engines - TFE731 Series\n\n \n\nAD/TFE731/8 Second Stage Turbine Disc Inspection 3/86\n\nApplicability: TFE 731 series as listed in Garrett SB TFE 731-72-3252 Rev 1. Document:  Garrett SB. TFE 731-72-3252 Rev. 1., or AD/AIR-T/46 Amdt 1.\n\nCompliance: At first access or next scheduled major periodic inspection, whichever occurs first.\n\n \n\nBackground: This Directive is raised in issue to include additional requirements of Revision 1 of Garrett SB TFE 731-72-3252.\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":{"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":true,"description":"The AD explicitly states it was issued to include additional requirements introduced by Revision 1 of Garrett SB TFE 731-72-3252. That indicates the directive expands or modifies previous requirements to incorporate the new items in SB Rev 1, thereby changing the scope of obligations on operators compared with the prior issuance."},"complexity_factors":["Short directive text with a single, clear action: inspection of second-stage turbine disc.","References an external document (Garrett SB TFE 731-72-3252 Rev. 1) for technical detail, requiring consult of that SB to implement.","Timing rule uses two possible triggers (first access or next scheduled major periodic inspection), which requires maintenance scheduling decisions.","Applicability limited to engines listed in the referenced SB, so implementers must cross-check engine serials/variants with the SB.","No detailed inspection procedures in the AD itself; technical complexity depends on the content of the referenced service bulletin."],"plain_english_summary":"This AD requires operators of AlliedSignal (Garrett/AiResearch) TFE731 engines to carry out the Garrett Service Bulletin TFE 731-72-3252 Rev 1 inspection of the second‑stage turbine disc at next engine access or the next major periodic inspection. It affects engine owners, operators and maintenance organisations listed in the SB, who must follow the SB’s inspection and corrective steps; compliance costs, downtime and any specialised repair demand fall to the operators."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, targeted airworthiness directive addressing a specific safety issue with a specific engine component. It has not expanded beyond its original technical safety purpose. The 'Background' note indicates this version simply updates requirements to match a revised manufacturer service bulletin — a routine maintenance of scope, not an expansion."},"complexity_factors":["Extremely short document (under 200 words)","No defined terms section — relies entirely on external technical documents (Garrett SB TFE 731-72-3252 Rev 1)","Single compliance trigger with simple alternative timing ('whichever occurs first')","No nested exceptions or conditional logic","Cross-references only to specific external technical bulletins, not to other legislative provisions","Purpose-built for a narrow, specific technical application (one engine series, one component)"],"plain_english_summary":"This is an **Airworthiness Directive (AD)** — essentially a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA). It requires owners and operators of certain **AlliedSignal (Garrett/AiResearch) TFE731 series turbine engines** to perform a specific inspection of the **second stage turbine disc**.\n\n**Who it affects:**\n- Aircraft operators using TFE731 series engines (common in business jets)\n- Maintenance organisations servicing these engines\n\n**What it requires:**\n- Operators must follow the inspection procedures outlined in **Garrett Service Bulletin TFE 731-72-3252 Revision 1** (or an alternative Australian directive AD/AIR-T/46 Amdt 1)\n- The inspection must happen at the **first opportunity** when the engine is opened up for maintenance, or at the **next major scheduled inspection** — whichever comes first\n\n**Why it matters:**\nThis directive was updated to incorporate new safety requirements from a revised service bulletin. Turbine discs operate under extreme stress and temperatures; failures can be catastrophic. The directive ensures potential defects are caught before they cause engine failure.\n\n**Key point:** This is a **compliance document**, not a law that creates new offences — but failing to follow it breaches civil aviation safety regulations and can ground aircraft or lead to enforcement action."}},"importantCases":[],"_links":{"self":"/api/acts/ad-tfe-731-8-second-stage-turbine-disc-inspection","history":"/api/acts/ad-tfe-731-8-second-stage-turbine-disc-inspection/history","analysis":"/api/acts/ad-tfe-731-8-second-stage-turbine-disc-inspection/analysis","conflicts":"/api/acts/ad-tfe-731-8-second-stage-turbine-disc-inspection/conflicts","importantCases":"/api/acts/ad-tfe-731-8-second-stage-turbine-disc-inspection/important-cases","documents":"/api/acts/ad-tfe-731-8-second-stage-turbine-disc-inspection/documents"}}