{"id":"F2006B07721","name":"Airworthiness Directives 2004 - Revocation and Remaking - AlliedSignal (Lycoming) Turbine Engines - T53 Series","slug":"airworthiness-directives-2004-revocation-and-remaking-alliedsignal-lycoming-turbine-engines-t53-seri","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":50453,"registerId":"commonwealth-F2006B07721-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"Airworthiness Directives 2004 - Revocation and Remaking - AlliedSignal (Lycoming) Turbine Engines - T53 Series","content":"Airworthiness Directives 2004\n\nI, DAVID ALAN VILLIERS, delegate of the Civil Aviation Safety\n\nAuthority, acting under subregulation 39.001 (1) of the Civil\n\nAviation Safety Regulations 1998:\n\n(a) revoke the Airworthiness Directives mentioned in\n\nSchedule 1; and\n\n(b) make, as separate instruments, each Airworthiness\n\nDirective mentioned in Schedule 1 and attached.\n\n![](image.001.png)\n\nDavid Villiers\n\nDelegate of the Civil Aviation Safety Authority\n\n20 December 2004\n\nNote: Each attached Airworthiness Directive is being re-made in exactly the\n\nsame form as appears in the latest published edition of the Directive.\n\n  \nSchedule 1 Revocation and Remaking of\n\nAirworthiness Directives\n\nAlliedSignal (Lycoming) Turbine Engines - T53 Series\n\nAD Name AD Number\n\nRotating Components - Service Life Limit - CANCELLED AD/T53/1 Amdt 2\n\nFirst Stage Power Turbine Rotor Blade Retaining Pins Retirement Life AD/T53/2\n\nRotating Component - Service Life Limits - CANCELLED AD/T53/3 Amdt 1\n\nEngine Oil Pump Drive Gear Spline - Inspection AD/T53/4\n\nAccessory Drive Gearbox - Rework AD/T53/5\n\nOverspeed Pickup Gear and Shaft - Inspection and Modification AD/T53/6\n\nImproved Gas Producer Turbine Rotor Blades - Introduction AD/T53/7\n\nSecond Stage Power Turbine Rotor Disc - Rework AD/T53/8\n\nSecond Stage Gas Producer Cylinder Bolts - Replacement AD/T53/9\n\nInlet Guide Vane Feedback Tube Assembly - Inspection AD/T53/10\n\nReplacement Of Compressor Rotor Discs and Impeller Assembly AD/T53/11\n\nFuel Regulator Main Pressure Regulator Valve Diaphragm Replacement AD/T53/12\n\nImproved Centrifugal Compressor Impeller - Introduction AD/T53/13\n\nTorque Meter Boost Pump - Replacement AD/T53/14\n\nFuel Regulator - P1 Multiplier Connector Assembly Damping AD/T53/15\n\nPower Turbine Clamping Plate - Inspection AD/T53/16\n\nCentrifugal Compressor Impellers AD/T53/17\n\nGas Producer and Power Turbine Discs and Spacers AD/T53/18\n\nN2 Accessory Drive AD/T53/19\n\nAccessory Drive Carrier AD/T53/20\n\nTachometer Drive Spur Gear AD/T53/21","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"No substantive change to regulatory scope. The instrument revokes and re-creates the listed ADs as separate instruments while keeping their content identical to the latest published editions (see Note and Schedule 1). Obligations on operators, maintainers and aircraft owners remain in force except where an AD is explicitly marked 'CANCELLED'."},"complexity_factors":["Administrative nature: revocation and remaking of instruments rather than substantive amendment reduces legal complexity","Number of ADs listed in Schedule 1 (multiple engine components and topics) increases operational complexity for affected operators","Cross-reference to Civil Aviation Safety Regulations 1998 (subreg 39.001(1)) creates a legal-basis dependency","Attachments/individual ADs are separate instruments — compliance tracking burden for operators and maintainers","Some entries explicitly marked 'CANCELLED' require attention to which obligations persist","Note stating each AD is remade 'in exactly the same form' reduces interpretive ambiguity but requires checking the attached texts"],"plain_english_summary":"This instrument revokes a package of Airworthiness Directives (ADs) applying to AlliedSignal (Lycoming) T53-series turbine engines and remakes each listed AD as a separate, current instrument. It preserves the existing mandatory inspection, maintenance and replacement requirements for operators, maintainers and aircraft owners who use T53 engines.\n\nThe change is made by a CASA delegate under subregulation 39.001(1) and is administrative in nature: each AD is reissued “in exactly the same form” as the latest published edition, so affected parties remain responsible for complying with the remade ADs."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"The legislation maintains its original narrow scope — administrative revocation and remaking of specific Airworthiness Directives for T53 engines. The note explicitly states each directive is being re-made in exactly the same form, confirming no scope creep."},"complexity_factors":["Very short document (approximately 400 words)","Only 1 defined term used (subregulation reference)","No conditional logic or nested exceptions","Simple binary structure: revoke (a) and make (b)","Schedule 1 is purely a table listing directive names and numbers","No cross-references to other legislation beyond the enabling regulation","Straightforward administrative remaking with no substantive changes to content"],"plain_english_summary":"This CASA order revokes and reissues 21 Airworthiness Directives for AlliedSignal (Lycoming) T53-series turbine engines—commonly fitted to Bell UH-1 and AH-1 helicopters—recreating them unchanged as fresh legal instruments. Two ADs (AD/T53/1 and AD/T53/3) are cancelled.\n\nIt’s housekeeping to preserve the ADs’ legal force; owners, operators, and maintenance organisations must continue to comply with the existing mandatory safety requirements."},"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/airworthiness-directives-2004-revocation-and-remaking-alliedsignal-lycoming-turbine-engines-t53-seri","history":"/api/acts/airworthiness-directives-2004-revocation-and-remaking-alliedsignal-lycoming-turbine-engines-t53-seri/history","analysis":"/api/acts/airworthiness-directives-2004-revocation-and-remaking-alliedsignal-lycoming-turbine-engines-t53-seri/analysis","conflicts":"/api/acts/airworthiness-directives-2004-revocation-and-remaking-alliedsignal-lycoming-turbine-engines-t53-seri/conflicts","importantCases":"/api/acts/airworthiness-directives-2004-revocation-and-remaking-alliedsignal-lycoming-turbine-engines-t53-seri/important-cases","documents":"/api/acts/airworthiness-directives-2004-revocation-and-remaking-alliedsignal-lycoming-turbine-engines-t53-seri/documents"}}