{"id":"F2006B07415","name":"AD/TFE 731/9 - L.P. Turbine Blade - Review, Inspection and Replacement","slug":"ad-tfe-731-9-l-p-turbine-blade-review-inspection-and-replacement","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":49657,"registerId":"commonwealth-F2006B07415-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/TFE 731/9 - L.P. Turbine Blade - Review, Inspection and 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/TFE731/9 L.P. Turbine Blade \\- Review, Inspection and Replacement\n\n  \n3/86\n\nApplicability: TFE 731-3 models listed by part number in the Requirement Document which have\n\nL.P. turbine rotor assemblies Part Number 3072352 installed. Requirement: AiResearch S.B. TFE 731-72-3225 Rev. 1.\n\n    Review engine life limited parts log cards to determine applicability in accordance with SB accomplishment instructions 'Note' of Para 2A.\n\n    2. Inspect/replace suspect blades of L.P. turbine rotor assy. Pt. No. 3072352 in accordance with S.B. accomplishment instructions Para 2A(1) to (12), or\n\n    3. AD/AIR-T/48.\n\nCompliance: For item 1 above: within 100 hours time in service after 31 July 1984.\n\nFor item 2 above:\n\n    (i) prior to exceeding 1100 cycles on suspect blades; or\n\n    (ii) at the next access to the L.P. rotor assembly; or\n    (iii) at the next scheduled major periodic inspection, whichever is the sooner. Background: The manufacturer has identified specific rotor assemblies which may contain L.P.\n\nturbine blades which have been subjected to an incorrect coating process during manufacture. This reduces the blade service life to 1100 cycles.","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":false,"description":"Scope aligns with the manufacturer's identification of affected rotor assemblies: it applies only to TFE731-3 engines with L.P. rotor assembly P/N 3072352 and imposes inspection/replacement deadlines because of an incorrect coating that reduces blade life to 1100 cycles (Applicability; Requirement; Background)."},"complexity_factors":["Part-specific applicability: targets TFE731-3 engines with L.P. turbine rotor assembly P/N 3072352 (Applicability).","Requires review of engine life-limited parts log cards to determine which engines/parts are affected (Requirement ¶1).","Cross-reference to manufacturer Service Bulletin (AiResearch S.B. TFE 731-72-3225 Rev.1) for detailed inspection and replacement instructions (Requirement).","Multiple compliance triggers and timeframes (within 100 hours after 31 July 1984; prior to exceeding 1100 cycles; at next access; or at next scheduled major inspection) (Compliance).","Alternative compliance path via another directive (AD/AIR-T/48) introduces coordination/choice (Requirement ¶3).","Technical judgement needed to identify ‘suspect’ blades and determine when an L.P. rotor assembly is considered 'accessed' or due for major inspection (Requirement ¶2; Compliance)."],"plain_english_summary":"This airworthiness directive requires operators of certain AlliedSignal TFE731-3 engines fitted with L.P. turbine rotor assembly P/N 3072352 to check maintenance records, inspect and replace any suspect low-pressure turbine blades (or follow the listed alternative AD). The measure enforces set deadlines tied to flight cycles and maintenance access because some blades received an incorrect coating that limits safe life to 1100 cycles."},"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This is a discrete, targeted safety directive addressing a specific manufacturing defect in specific engine models. It has not expanded beyond its original purpose of ensuring defective turbine blades are identified and replaced before failure."},"complexity_factors":["Short, single-purpose directive (approximately 200 words)","Only 3 defined compliance pathways (items 1, 2, and reference to AD/AIR-T/48)","Clear applicability criteria limited to specific part numbers","Simple conditional logic: 'whichever is the sooner' for compliance timing","No nested exceptions or cross-references to other legislation beyond one alternative directive (AD/AIR-T/48)","Single technical reference document (Service Bulletin TFE 731-72-3225 Rev. 1)"],"plain_english_summary":"This Airworthiness Directive orders owners, operators and maintenance organisations of certain AlliedSignal (Garrett/AiResearch) TFE731-3 engines (notably those with L.P. turbine rotor assembly P/N 3072352) to verify whether potentially miscoated low-pressure turbine blades are installed and to inspect or replace them before they exceed a reduced safe life of 1,100 flight cycles.\n\nIt matters because the incorrect coating sharply shortens blade life, and failure in service could cause catastrophic engine damage and loss of aircraft control."}},"importantCases":[],"_links":{"self":"/api/acts/ad-tfe-731-9-l-p-turbine-blade-review-inspection-and-replacement","history":"/api/acts/ad-tfe-731-9-l-p-turbine-blade-review-inspection-and-replacement/history","analysis":"/api/acts/ad-tfe-731-9-l-p-turbine-blade-review-inspection-and-replacement/analysis","conflicts":"/api/acts/ad-tfe-731-9-l-p-turbine-blade-review-inspection-and-replacement/conflicts","importantCases":"/api/acts/ad-tfe-731-9-l-p-turbine-blade-review-inspection-and-replacement/important-cases","documents":"/api/acts/ad-tfe-731-9-l-p-turbine-blade-review-inspection-and-replacement/documents"}}