{"id":"F2006B07395","name":"AD/TFE 731/11 - H.P. Turbine Blades P/N 3072455-10 Replacement","slug":"ad-tfe-731-11-h-p-turbine-blades-p-n-3072455-10-replacement","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":49590,"registerId":"commonwealth-F2006B07395-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/TFE 731/11 - H.P. Turbine Blades P/N 3072455-10 Replacement","content":"COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 \\- 106 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n![](image.001.png)  \nAlliedSignal (Garrett/AiResearch) Turbine Engines \\- TFE731 Series\n\nAD/TFE731/11 H.P. Turbine Blades\n\nP/N 3072455-10 Replacement\n\n  \n3/86\n\nApplicability: TFE 731-2-1C; \\-2-2B fitted with H.P. Turbine Rotor assemblies P/N 3072570-6, \\-7,\n\n\\-9, \\-10, with blades P/N 3072455-10 not frequency inspected or mixed with any other P/N H.P. Turbine blades.\n\nRequirement: Garrett S.B. TFE 731-72-3291 Rev 1 of 24 May 1985; or\n\nAD/AIR-T/52 Amdt 1.\n\nNote: This document refers to S.B. TFE 731-72-3220 which is to be reviewed and accomplished, if applicable, coincident with this directive, to remove from service those blades P/N 3072455-10 manufactured from GMR 235 material.\n\nEffectivity: Unless already accomplished, at the next removal of the H.P. Turbine Rotor assembly or at the next scheduled major periodic inspection after 31 March 1985 whichever is the sooner.\n\nBackground: a. As a result of investigation into 39 fatigue related blade separations the manufacturer has developed a frequency scan inspection. Blades not frequency inspected were fitted to rotor assemblies by the manufacturer prior to March 1980\\. This directive removes from service those blades P/N 3072455-10 which have not been frequency inspected, or which have been mixed with other P/N blades, or which were manufactured from GMR 235 material.\n\nb. This Amendment reflects the manufacturer's Revision 1 advice to the Requirement Document which now includes H.P. Turbine Rotor Assemblies P/N. 3072570-6, \\-9 that may contain H.P. Turbine Blades P/N 3072455-10 improperly identified as P/N 3072455-12.","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This AD maintains its original narrow scope. It targets a specific safety defect in specific engine models with specific part numbers. The amendment (noted in the background) merely expands the list of affected rotor assemblies to include those with misidentified blades — this is a clarification of coverage, not scope creep. The directive remains tightly focused on the original problem: preventing fatigue failures in H.P. turbine blades."},"complexity_factors":["Short, single-purpose directive (approximately 250 words)","Only 4 defined part numbers and 2 engine models in applicability section","Simple binary compliance requirement: replace the blades or inspect per specified service bulletin","Clear deadline mechanism (next removal or next major inspection after fixed date)","No nested exceptions or conditional logic — straightforward applicability test","Single cross-reference to manufacturer service bulletin and one other AD","Background section provides plain-language explanation of safety rationale"],"plain_english_summary":"This CASA Airworthiness Directive mandates removal and replacement of AlliedSignal (Garrett/AiResearch) H.P. turbine blades P/N 3072455-10 from certain TFE731-2-1C and TFE731-2-2B engines (rotors ending in -6, -7, -9, -10) if blades lack a frequency-scan inspection, were mixed with different P/N blades on the same rotor, or are made from GMR 235. It responds to repeated fatigue failures (39 separations) that can destroy an engine in flight, requiring replacement at the next rotor removal or next major inspection after 31 March 1985."},"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":true,"description":"This Amendment expands the directive's scope to include additional H.P. turbine rotor assemblies (P/N 3072570-6 and -9) that may contain blades improperly identified as P/N 3072455-12, and clarifies removal of blades manufactured from GMR 235. Source: Background b and Note."},"complexity_factors":["Technical inspection requirement: compliance requires a specialist frequency-scan inspection method developed after fatigue events (Requirement; Background a).","Parts identification risk: blades may be misidentified or mixed with other P/Ns, requiring historical traceability and possible physical verification (Applicability; Background b).","Material issue: blades manufactured from GMR 235 are specifically excluded and must be identified and removed (Note; Background a).","Multiple referenced documents: compliance depends on following the manufacturer's Service Bulletin Rev 1 and an earlier AD (Requirement), creating cross‑document dependency.","Timing conditionality: effectivity is at next rotor removal or next scheduled major periodic inspection, so operators must track maintenance cycles to comply (Effectivity).","Safety consequence sensitivity: inspection/removal decisions are safety‑critical and may impose operational downtime and replacement costs on operators (Background a; Effectivity)."],"plain_english_summary":"Mechanically, this directive requires removal from service of H.P. turbine blades P/N 3072455-10 on certain TFE731-2 engines unless the blades have passed the manufacturer's frequency-scan inspection, are not mixed with other part‑numbers, and are not made from GMR 235 material. It affects operators of TFE731-2-1C and -2-2B engines fitted with the listed rotor assemblies; CASA issues the directive, and operators must pay for inspections or replacements at the next rotor removal or at the next major periodic inspection (Applicability; Requirement; Effectivity; Background a–b)."},"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"}},"importantCases":[],"_links":{"self":"/api/acts/ad-tfe-731-11-h-p-turbine-blades-p-n-3072455-10-replacement","history":"/api/acts/ad-tfe-731-11-h-p-turbine-blades-p-n-3072455-10-replacement/history","analysis":"/api/acts/ad-tfe-731-11-h-p-turbine-blades-p-n-3072455-10-replacement/analysis","conflicts":"/api/acts/ad-tfe-731-11-h-p-turbine-blades-p-n-3072455-10-replacement/conflicts","importantCases":"/api/acts/ad-tfe-731-11-h-p-turbine-blades-p-n-3072455-10-replacement/important-cases","documents":"/api/acts/ad-tfe-731-11-h-p-turbine-blades-p-n-3072455-10-replacement/documents"}}