{"id":"F2006B07411","name":"AD/TFE 731/5 - Compressor Tie Rod - Replacement","slug":"ad-tfe-731-5-compressor-tie-rod-replacement","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":49643,"registerId":"commonwealth-F2006B07411-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/TFE 731/5 - Compressor Tie Rod - 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/TFE731/5 Compressor Tie Rod \\- Replacement 3/86\n\nApplicability: All TFE731-2-1C, \\-2-2B, \\-3-1E, \\-3-1G, \\-3-1F, \\-3-1C, \\-3-1H, \\-2-2J, \\-3-1K models.\n\nDocument: AiResearch Alert SB No. TFE731-A72-3140, or AD/AIR-T/37.\n\nRequirement: Part 1 \\- For engines listed by their S/Nos. in paragraph \"D\" of the requirement document:\n\nChange the compressor tie rod in accordance with the requirement document.\n\nPart 2 \\- For all applicable models whose engine S/Nos. is not listed in Paragraph \"D\" of requirement document:\n\nReplace any compressor tie rod of a S/No. listed under the heading of \"Special Category\" in Paragraph \"D\" of the requirement document.\n\nCompliance: Part 1 \\- Within 100 hours time in service after 30 September 1980.\n\nPart 2 \\- At the next hot end inspection or at the next time access to the area is gained for another purpose whichever occurs first.\n\nBackground: This Directive is issued as the result of notification from the engine manufacturer that some tie rods made from suspect material were used during engine manufacture or overhaul.","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This AD remains tightly focused on its original purpose: addressing a specific manufacturing defect in compressor tie rods for TFE731 engines. The scope has not expanded beyond this safety-critical component replacement."},"complexity_factors":["Short, single-purpose directive (approximately 200 words)","Only 2 defined compliance paths (Part 1 and Part 2) based on serial number matching","Minimal cross-referencing (only references one manufacturer service bulletin and one related AD)","Simple conditional logic: 'if serial number in list D, do X; if not in list D but part number in Special Category, do Y'","No nested exceptions or sub-exceptions","Clear, fixed compliance dates and triggers (100 hours TIS, or next inspection/access)","Single technical subject matter (one component replacement on one engine series)"],"plain_english_summary":"This CASA Airworthiness Directive orders mandatory replacement of certain compressor tie rods on AlliedSignal (Garrett/AiResearch) TFE731 engines because some rods were made from suspect material that could fail and cause catastrophic engine loss. It applies to engines and tie-rod serial numbers identified by the manufacturer; some engines required replacement within 100 flight hours after 30 September 1980, while others could wait until the next scheduled inspection if only specific tie-rod serials were affected."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The directive targets engines and specific tie rods identified by the manufacturer as suspect and mandates replacement per the referenced service document. The text shows no indication the scope was expanded or narrowed beyond addressing the manufacturer’s notification (engines listed in Paragraph D or ties in the 'Special Category')."},"complexity_factors":["References an external requirement document (AiResearch Alert SB No. TFE731-A72-3140 / AD/AIR-T/37) and a serial-number list in 'Paragraph D', requiring cross-checking external material.","Two-part requirement structure: Part 1 applies to engines with S/Ns listed in Paragraph D; Part 2 applies to other engines but targeting tie rods with S/Ns in a 'Special Category' — creates conditional applicability.","Different compliance triggers and timings (within 100 hours after 30 Sep 1980 versus at next hot-end inspection or next access) require operational scheduling and record checks.","Applicability spans multiple TFE731 model variants, so fleet managers must identify affected engines across airframes.","Cost and logistics of parts replacement and access/inspection fall to operators and maintenance organisations; procurement and downtime planning required."],"plain_english_summary":"This directive requires replacement of compressor tie rods on specified AlliedSignal TFE731 engine models and serial numbers, using the manufacturer's service document. It affects aircraft operators and maintenance organisations that must remove and fit replacement tie rods. The action responds to manufacturer advice that some tie rods were made from suspect material, and sets compliance deadlines — within 100 flight hours or at the next hot-end inspection/access — to address the risk of component failure."}},"importantCases":[],"_links":{"self":"/api/acts/ad-tfe-731-5-compressor-tie-rod-replacement","history":"/api/acts/ad-tfe-731-5-compressor-tie-rod-replacement/history","analysis":"/api/acts/ad-tfe-731-5-compressor-tie-rod-replacement/analysis","conflicts":"/api/acts/ad-tfe-731-5-compressor-tie-rod-replacement/conflicts","importantCases":"/api/acts/ad-tfe-731-5-compressor-tie-rod-replacement/important-cases","documents":"/api/acts/ad-tfe-731-5-compressor-tie-rod-replacement/documents"}}