{"id":"F2006B07408","name":"AD/TFE 731/31 - HP Compressor Impeller","slug":"ad-tfe-731-31-hp-compressor-impeller","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":49633,"registerId":"commonwealth-F2006B07408-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"AIRWORTHINESS DIRECTIVE","sectionType":"part","heading":"AIRWORTHINESS DIRECTIVE","content":"# AIRWORTHINESS DIRECTIVE\n\n![](image.001.png)\n\n![](image.001.png)  \nFor the reasons set out in the background section, the CASA delegate whose signature appears below issues the following Airworthiness Directive (AD) under subregulation 39.1 (1) of CAR 1998. The AD requires that the action set out in the requirement section (being action that the delegate considers necessary to correct the unsafe condition) be taken in relation to the aircraft or aeronautical product mentioned in the applicability section: (a) in the circumstances mentioned in the requirement section; and (b) in accordance with the instructions set out in the requirement section; and (c) at the time mentioned in the compliance section.\n\nAlliedsignal (Garrett/Airesearch) Turbine Engines \\- TFE 731 Series","sortOrder":0},{"sectionNumber":"AD/TFE731/31 HP Compressor Impeller 4/20","sectionType":"part","heading":"AD/TFE731/31 HP Compressor Impeller 4/2001","content":"# AD/TFE731/31 HP Compressor Impeller 4/2001\n\nApplicability: TFE731 engines detailed by model in Honeywell Alert Service Bulletin TFE731- A72-3641 Revision 2 incorporating a high pressure compressor (HPC) impeller part number (P/N) 3073393-1, 3073394-1, 3073433-1, 3073434-1, 3073398-All,\n\n3073435-All, 3075171-All, 3075765-1, 3075768-1 and 3075769-1.\n\nRequirement: Remove and inspect applicable HPC impeller in accordance with Honeywell Alert Service Bulletin TFE731-A72-3641 Revision 2.\n\nNote: FAA AD 2000-15-09 refers.\n\nCompliance: 1. From the effective date of this Directive; at the next compressor zone inspection or access to the HPC module, whichever occurs first, and\n\n    2. Thereafter at each compressor zone inspection, or\n\n    3. At next access to the HPC module if the HPC impeller has accumulated more than 1,000 cycles since last eddy current inspection (ECI).\n\nThis Airworthiness Directive becomes effective on 19 April 2001.\n\nBackground: This Directive has been issued to require removal and inspection of certain HPC impellers by part number. The FAA has determined that low cycle fatigue cracking in the high stress areas of the impeller may led to an uncontained impeller separation.\n\n![Signature of Eugene Paul Holzapfel Delegate of the Civil Aviation Safety Authority](image.002.png)  \n\nEugene Paul Holzapfel\n\nDelegate of the Civil Aviation Safety Authority 8 March 2001\n\n![](image.001.png)  \n\nThe above AD is notified in the Commonwealth of Australia Gazette on 21 March 2001.","sortOrder":1}],"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"},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The supplied AD text imposes inspection requirements for a defined set of HPC impeller part numbers consistent with the FAA finding of low‑cycle fatigue. The instrument itself does not indicate any expansion or narrowing of scope beyond those specified part numbers or the timing conditions set out in the Compliance paragraph."},"complexity_factors":["Single, safety‑critical corrective action: removal and eddy‑current inspection of specified HPC impellers (Requirement; Compliance).","Applicability limited to specific impeller part numbers listed in the service bulletin, requiring part‑level identification during maintenance.","Conditional compliance timing: next compressor‑zone inspection, next HPC access, or earlier if >1,000 cycles since last ECI—requires engine cycle tracking.","Dependence on an external document (Honeywell Alert Service Bulletin TFE731‑A72‑3641 Rev 2) for inspection instructions.","Reference to FAA AD 2000‑15‑09 as related authority, introducing cross‑jurisdictional technical alignment.","Operational burden: scheduling HPC access or inspections may require additional maintenance downtime and remove/replace effort."],"plain_english_summary":"This Airworthiness Directive requires operators and maintainers of Alliedsignal/Honeywell TFE731 series engines fitted with specified high‑pressure compressor (HPC) impeller part numbers to remove and inspect those impellers in line with Honeywell Alert Service Bulletin TFE731‑A72‑3641 Revision 2. Compliance is required at the next compressor‑zone inspection or the next access to the HPC module (or sooner if an impeller has accumulated more than 1,000 cycles since its last eddy‑current inspection). CASA cites FAA findings of low‑cycle fatigue that can lead to uncontained impeller separation; operators pay inspection and access costs."},"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This AD maintains its original narrow scope — addressing a specific safety defect in specific engine part numbers. It has not expanded beyond its initial purpose of mandating inspection for fatigue cracking in HPC impellers."},"complexity_factors":["Short, single-purpose directive (approximately 300 words)","Only 3 main operative sections: Applicability, Requirement, and Compliance","10 specific part numbers listed but no complex cross-referencing between sections","Simple conditional logic in compliance section (3 alternative timing triggers)","Single external reference to Honeywell Service Bulletin and FAA AD 2000-15-09","No defined terms section — technical terms (HPC, ECI) used in context without formal definitions","Clear, linear structure without nested exceptions or sub-delegations"],"plain_english_summary":"Owners/operators of Honeywell TFE731 engines fitted with certain HPC impeller part numbers must remove and inspect those impellers for cracking. CASA mandates this action because the FAA found low-cycle fatigue can cause uncontained impeller separation, risking aircraft damage and lives. The AD applies to engines with the listed part numbers and directs inspections at the next compressor access or inspection interval, using Honeywell’s service bulletin procedures."}},"importantCases":[],"_links":{"self":"/api/acts/ad-tfe-731-31-hp-compressor-impeller","history":"/api/acts/ad-tfe-731-31-hp-compressor-impeller/history","analysis":"/api/acts/ad-tfe-731-31-hp-compressor-impeller/analysis","conflicts":"/api/acts/ad-tfe-731-31-hp-compressor-impeller/conflicts","importantCases":"/api/acts/ad-tfe-731-31-hp-compressor-impeller/important-cases","documents":"/api/acts/ad-tfe-731-31-hp-compressor-impeller/documents"}}