{"id":"F2006B11177","name":"AD/LTS/14 - Power Turbine Rotor","slug":"ad-lts-14-power-turbine-rotor","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":56875,"registerId":"commonwealth-F2006B11177-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/LTS/14 - Power Turbine Rotor","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 (Lycoming) Turbine Engines \\- LTS 101 Series\n\nAD/LTS/14 Power Turbine Rotor 10/96\n\nApplicability: All LTS101 series engines, other than the LTS101-750B-2 model.\n\nRequirement: To prevent power turbine rotor failure resulting in the loss of engine power, identify the serial number of the power turbine rotor assembly installed in applicable engines and remove from service rotor assemblies as listed by serial number in Textron Lycoming Service Bulletin Number LT 101-72-50-0144.\n\nNote: FAA Airworthiness Directive 96-12-05 refers.\n\nCompliance: As detailed in the requirement document with an effective date of 12 September 1996.\n\nBackground: This directive has been issued to require the removal from service of certain power turbine rotor assemblies. The requirement reflects advice from the manufacturer of workmanship deficiencies in certain power turbine discs that could result in a reduction of the fatigue life of those discs.","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, targeted safety directive addressing a specific manufacturing defect in specific engine models. The scope remains tightly focused on the original safety issue without expansion into broader operational or maintenance requirements."},"complexity_factors":["Very short document (approximately 200 words)","Only 1 defined applicability criterion (engine model exclusion)","Single, straightforward requirement with clear action (identify serial number, remove if listed)","No nested conditional logic or exceptions","Cross-reference to only 1 external document (FAA AD 96-12-05) and 1 manufacturer service bulletin","No interpretation section or defined terms"],"plain_english_summary":"This is an **Airworthiness Directive (AD)** — essentially a mandatory safety order for aircraft engines. It applies to **AlliedSignal (Lycoming) LTS 101 series turbine engines** (except one specific model, the LTS101-750B-2).\n\n**What it does:**\n- Requires aircraft operators to **check the serial numbers** of their engine's power turbine rotor assemblies\n- **Mandates removal from service** of specific rotor assemblies identified in a manufacturer service bulletin (LT 101-72-50-0144)\n\n**Why it matters:**\nCertain power turbine discs were manufactured with **workmanship defects** that reduce their fatigue life. If these rotors aren't removed, they could fail in flight, causing **complete engine power loss** — a serious safety risk.\n\n**Who must comply:**\nAnyone operating aircraft with these engines must follow this directive, with compliance required by **12 September 1996**.\n\n**Key point:** This isn't optional maintenance advice — it's a **legally binding safety requirement** issued by the Civil Aviation Safety Authority (CASA) under Commonwealth aviation regulations."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The directive’s scope aligns with the stated original intent in the document: to require the removal from service of specific power turbine rotor assemblies identified because of manufacturer-advised workmanship deficiencies. The applicability is limited to LTS101 series engines except the LTS101-750B-2 model, and the requirement is to follow the serial-number list in the named Textron Lycoming service bulletin. The instrument does not expand its scope to other components or broader classes of engines beyond that stated intention. (Applicability; Requirement; Background)"},"complexity_factors":["Narrow technical focus limited to power turbine rotor assemblies in LTS101 series engines (Applicability)","Mandatory action is defined by reference to an external manufacturer service bulletin rather than by listing serial numbers in the text (Requirement)","Compliance requires serial-number identification and physical removal, imposing operational and administrative tasks on owners/operators (Requirement)","Effective compliance date is specified but the directive does not detail replacement, remediation, or cost allocation (Compliance; Requirement)","Delegation to manufacturer for the substantive list creates dependence on an external document and cross-reference to FAA AD for related context (Requirement; Note)"],"plain_english_summary":"What this directive does (mechanically)\n\n- It requires operators/owners of affected AlliedSignal (Lycoming) LTS101 turbine engines to identify the serial number of the power turbine rotor assembly fitted to each engine and to remove from service those rotor assemblies that appear on a serial-number list published in Textron Lycoming Service Bulletin Number LT 101-72-50-0144. (Requirement)\n- The Compliance provision makes the directive effective from 12 September 1996. (Compliance)\n\nWho it affects\n\n- All LTS101 series engines except the LTS101-750B-2 model. The directive applies to engines meeting that applicability statement. (Applicability)\n- The immediate actors who must act are the owners/operators of those engines: they must identify serial numbers and remove any listed assemblies. The directive itself does not specify who supplies replacements or pays for them. (Requirement)\n\nWhy the directive was issued (source's stated purpose)\n\n- The directive states its purpose is to prevent power turbine rotor failure that could lead to loss of engine power. It cites manufacturer advice of workmanship deficiencies in certain power turbine discs that could reduce fatigue life. (Requirement; Background)\n\nTesting that stated purpose against practical mechanics, costs, incentives and risks\n\n- Mechanism: The regulatory action delegates the detailed list of affected parts to the manufacturer’s service bulletin. The regulator mandates compliance with that list rather than publishing the list directly. That means the operational effect (which serial numbers must be removed) is governed by the service bulletin named in the Requirement. (Requirement)\n\n- Who pays / who decides: The directive obliges owners/operators to identify and remove listed rotor assemblies. The text does not specify funding, replacement provision, or indemnity, so the directive does not itself allocate payment responsibility. Any cost of removing or replacing assemblies is not described in this instrument. (Requirement; Compliance)\n\n- Compliance burden and implementation risk: Operators must inspect serial numbers against an external manufacturer document and remove identified parts. That creates an administrative and operational burden (inspection, removal, out-of-service time). The directive sets an effective date for compliance but does not set out procedures for replacement or return-to-service in this text. (Requirement; Compliance)\n\n- Bureaucratic discretion and delegation: The directive relies on the manufacturer’s service bulletin to identify specific affected serial numbers. That delegates substantive technical identification to the manufacturer instead of listing them in the directive. (Requirement)\n\n- Incentives and trade-offs for private parties: Operators face a trade-off between complying (removing parts and incurring inspection and maintenance time) and the safety risk the directive addresses. The directive reduces the ability of an operator to continue using a rotor assembly if it appears on the manufacturer’s list. The instrument does not discuss supply of replacements or market effects such as price or availability of spare rotor assemblies. (Requirement; Background)\n\n- Opportunity costs and substitution effects: The directive may cause engines to be withdrawn from service while affected rotors are removed; the text does not specify mitigations such as temporary approvals or alternative parts. Any operational substitution (use of different engines, leasing, or deferred flights) is not addressed here. (Requirement; Background)\n\n- Concentrated benefits and diffuse costs: The stated benefit (reducing risk of rotor failure) accrues to any user of the affected engines and to airworthiness generally; the immediate compliance costs (inspection, removal, maintenance downtime and replacement) would fall on the specific owners/operators of the affected engines. The directive text does not indicate compensation or sharing of those costs. (Requirement; Background)\n\nOther cross-references\n\n- The directive notes a corresponding FAA Airworthiness Directive (96-12-05) as a reference. (Note)\n\nSummary statement\n\n- In practical terms, this instrument forces identification and removal from service of certain power turbine rotor assemblies in most LTS101 engines by reference to a manufacturer’s serial-number list. It cites manufacturer-reported workmanship deficiencies as the reason. The directive prescribes what owners/operators must do but delegates the precise identification of affected parts to the named service bulletin and does not, within this text, specify cost allocation, replacement procedures or remedial steps beyond removal. (Applicability; Requirement; Background; Compliance)"}},"importantCases":[],"_links":{"self":"/api/acts/ad-lts-14-power-turbine-rotor","history":"/api/acts/ad-lts-14-power-turbine-rotor/history","analysis":"/api/acts/ad-lts-14-power-turbine-rotor/analysis","conflicts":"/api/acts/ad-lts-14-power-turbine-rotor/conflicts","importantCases":"/api/acts/ad-lts-14-power-turbine-rotor/important-cases","documents":"/api/acts/ad-lts-14-power-turbine-rotor/documents"}}