{"id":"F2006B11180","name":"AD/LTS/17 - Compressor Impeller","slug":"ad-lts-17-compressor-impeller","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":56879,"registerId":"commonwealth-F2006B11180-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"AIRWORTHINESS DIRECTIVE","sectionType":"part","heading":"AIRWORTHINESS DIRECTIVE","content":"# ![](image.001.png)  \nAIRWORTHINESS DIRECTIVE\n\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\n![](image.001.png)\n\nAlliedSignal (Lycoming) Turbine Engines \\- LTS 101 Series","sortOrder":0},{"sectionNumber":"AD/LTS/17 Compressor Impeller 6/2002","sectionType":"part","heading":"AD/LTS/17 Compressor Impeller 6/2002","content":"# AD/LTS/17 Compressor Impeller 6/2002\n\nApplicability: LTS 101Series turboshaft engines incorporating a centrifugal compressor impeller part numbers 4-101-052-57 or 4-101-052-62, except for impellers with serial numbers or part numbers listed in paragraphs 1.A. (1) through 1.A. (3) in Honeywell Service Bulletin (SB) LT 101-72-30-0186 Revision 1, or AlliedSignal SB LT 101-72-30- 0186.\n\nRequirement: 1. Visual / Fluorescent Inspection: Conduct a one time visual inspection for surface finish, and fluorescent inspection of impellers as per the accomplishment instructions of Honeywell SB LT 101-72-30-0186 Revision 1, or AlliedSignal SB LT 101-72-30-0186.\n\n    2. Impeller Removal: Remove from service all impellers that exceed the acceptable limits of the accomplishment instructions of Honeywell SB LT 101- 72-30-0186 Revision 1, or AlliedSignal SB LT 101-72-30-0186.\n\n    3. Impeller Replacement: Impellers with part numbers as listed in applicability of this Directive shall not be fitted unless the inspection criteria of Honeywell SB LT 101-72-30-0186 Revision 1, or AlliedSignal SB LT 101-72-30-0186 is met.\n\nNote: FAA AD 2002-03-09 R1 refers.\n\nCompliance: 1. Visual / Fluorescent Inspection: Unless previously accomplished; within 900 gas generator (Ng) cycles after the effective date of this Directive.\n\n    2. Impeller Replacement: Before further flight.\n\n    3. Spare Impellers: Prior to installation in an aircraft.\n\nThis Airworthiness Directive becomes effective on 13 June 2002.","sortOrder":1}],"analysis":{"flash_summary_failed":{"failed":true,"reason":"Unauthenticated. Configure AI_GATEWAY_API_KEY or use a provider module. Learn more: https://ai-sdk.dev/unauthenticated-ai-gateway","source":"analysis-cron"},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The Directive sticks to the manufacturer’s corrective action: it applies only to LTS 101 engines with the listed impeller part numbers and defers to Honeywell/AlliedSignal Service Bulletin LT 101-72-30-0186 (Requirement). Exceptions for specific serial/part numbers are those listed in the SB (Applicability). Actions are limited to inspection, removal and replacement with defined compliance windows (Compliance). There is no expansion beyond the SB’s technical scope."},"complexity_factors":["Narrow applicability: specific impeller part numbers only (Applicability).","Reliance on external manufacturer service bulletin for inspection criteria and limits (Requirement cites Honeywell/AlliedSignal SB LT 101-72-30-0186 Rev 1).","Technical inspection method required (visual + fluorescent), which requires trained personnel and equipment (Requirement 1).","Quantified compliance metric based on engine cycles (900 Ng cycles) rather than calendar time (Compliance 1).","Immediate operational consequence for defects (remove before further flight) creates potential aircraft downtime and replacement cost (Requirement 2; Compliance 2).","Restriction on fitting spare impellers unless they meet SB criteria (Requirement 3; Compliance 3) affecting spare‑parts inventory management."],"plain_english_summary":"This Airworthiness Directive requires operators of AlliedSignal (Lycoming) LTS 101 turboshaft engines fitted with specific centrifugal compressor impeller part numbers to carry out a one‑time visual and fluorescent inspection, remove and replace impellers that exceed the allowable limits, and not fit those impellers unless they meet the inspection criteria. Operators pay for and arrange the inspections and any replacements; the CASA delegate enforces the Directive under CAR 1998 subregulation 39.1(1). Key deadlines: inspection within 900 gas‑generator (Ng) cycles; removal before further flight; spares checked before installation."},"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This is a standard airworthiness directive with a narrow, specific safety purpose — addressing a known defect in particular engine components. It has not expanded beyond its original intent of mandating inspection and replacement of faulty compressor impellers."},"complexity_factors":["Short, single-purpose directive with only 3 requirements","Heavy reliance on external technical documents (Honeywell/AlliedSignal Service Bulletins) for actual inspection procedures — the AD doesn't spell out the inspection method itself","Cross-reference to FAA AD 2002-03-09 R1 for additional context","Conditional applicability based on part numbers AND serial numbers, requiring cross-checking against an external service bulletin list","Three different compliance deadlines depending on the action (inspection, removal, spare parts installation)"],"plain_english_summary":"This CASA safety order requires operators and maintainers of AlliedSignal/Honeywell LTS 101 helicopter engines with specific impeller part numbers to inspect compressor impellers for cracks using visual and fluorescent dye checks within 900 engine cycles (from 13 June 2002). Failed impellers must be removed before flight and spares cannot be fitted unless inspected; exemptions apply only if a Honeywell service bulletin lists the serial number. The rule prevents uncontained impeller failure and catastrophic engine loss."}},"importantCases":[],"_links":{"self":"/api/acts/ad-lts-17-compressor-impeller","history":"/api/acts/ad-lts-17-compressor-impeller/history","analysis":"/api/acts/ad-lts-17-compressor-impeller/analysis","conflicts":"/api/acts/ad-lts-17-compressor-impeller/conflicts","importantCases":"/api/acts/ad-lts-17-compressor-impeller/important-cases","documents":"/api/acts/ad-lts-17-compressor-impeller/documents"}}