{"id":"F2021L01090","name":"AD/LTS/13 Amdt 1 Improved Power Turbine Retention","slug":"ad-lts-13-amdt-1-improved-power-turbine-retention","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":101998,"registerId":"commonwealth-F2021L01090-current","compilationNumber":null,"startDate":"2026-04-03","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"Honeywell International Turbine Engines ","sectionType":"part","heading":"Honeywell International Turbine Engines - LTS 101 Series","content":"# Honeywell International Turbine Engines - LTS 101 Series\n\n| AD/LTS/13 Amdt 1 | Improved Power Turbine Retention | 16/2021 |\n| ---------------- | -------------------------------- | ------- |\n\n| Applicability: | Honeywell International (formerly AlliedSignal and Textron Lycoming) LTS101‑650B1, -750B1, -650C and -750C model turboshaft engines. |\n| -------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement: | 1. To prevent a power turbine overspeed and an uncontained engine failure, install an improved power turbine retention system and improved power turbine rotor assembly in accordance with the following Honeywell International Service Bulletins (SBs):(a) LTS 101B-72-50-0122 Revision 4 as in force on the commencement date of this AD, or(b) LTS 101B-72-50-0116 Revision 6 as in force on the commencement date of this AD, or(c) LTS 101C-72-50-0119 Revision 2 as in force on the commencement date of this AD, as applicable, and2. Install an improved electronic power turbine rotor overspeed controller in accordance with the following Honeywell International SBs:(a) LTS 101B-73-10-0127 Revision 2 as in force on the commencement date of this AD, or(b) LTS 101C-73-10-0129 Revision 3 as in force on the commencement date of this AD, as applicable.Note 1: United States of America Federal Aviation Administration (FAA) AD 95‑26‑01 is the basis for this AD.Note 2: CASA Airworthiness Directives AD/JBK 117/9, AD/GBK 117/7 and AD/BELL 222/19, as in force from time to time, address the airframe wiring requirements for the installation of an electronic power turbine overspeed controller. |\n| Compliance: | Requirement 1. Before further flight after the commencement date of this AD, unless accomplished previously.Requirement 2. Concurrent with Airworthiness Directives AD/JBK 117/9, AD/GBK 117/7 and AD/BELL 222/19, as applicable, but before further flight after the commencement date of this AD, unless accomplished previously. |\n| | This AD commences on 20 August 2021. |\n\n| Background: | This Directive has been issued to require the installation of an improved power turbine rotor and an improved power turbine rotor overspeed controller. The requirements address reports of uncontained power turbine failure events.Amendment 1 removes obsolete references and makes minor editorial changes to reflect current requirements. |\n| ----------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n\n![Text\nDescription automatically generated](image.001.jpeg)\n\nDavid Punshon \nDelegate of the Civil Aviation Safety Authority\n\n6 August 2021","sortOrder":0},{"sectionNumber":"AD/LTS/13 Amdt 1","sectionType":"part","heading":"AD/LTS/13 Amdt 1","content":"## AD/LTS/13 Amdt 1","sortOrder":1},{"sectionNumber":"Improved Power Turbine Retention","sectionType":"part","heading":"Improved Power Turbine Retention","content":"## Improved Power Turbine Retention","sortOrder":2},{"sectionNumber":"16/2021","sectionType":"part","heading":"16/2021","content":"## 16/2021","sortOrder":3}],"analysis":{"flash_summary":{"complexity_score":5,"scope_assessment":{"changed":false,"description":"Amendment 1 removes obsolete references and makes minor editorial changes but does not alter the substantive technical requirements. The directive still mandates the same installations for the listed LTS101 engine models (Background; Requirement)."},"complexity_factors":["Targeted applicability to specific engine models (LTS101‑650B1, ‑750B1, ‑650C, ‑750C) creates a narrow affected population but requires engine-level work (Applicability).","Requirement to install both mechanical retention/rotor parts and an electronic overspeed controller increases technical scope and integration complexity (Requirement 1 & 2).","Mandatory compliance timing: installations must be completed before further flight after the AD commencement, imposing immediate grounding/repair scheduling pressure on operators (Compliance).","Reference to multiple Honeywell Service Bulletins by revision and the phrase 'as in force on the commencement date' means operators must match specific SB revisions in force at the AD start, adding document-versioning complexity (Requirement).","Concurrent wiring-related airworthiness directives for airframe installations are mandated for the controller installation, creating coordination needs with airframe owners/operators and additional work scope (Requirement Note 2; Compliance).","Regulatory linkage to a foreign authority (FAA AD 95‑26‑01) and to CASA ADs increases cross-reference complexity for compliance verification (Requirement Note 1; Requirement Note 2).","Amendment 1 states it removes obsolete references and makes editorial changes, indicating no substantive technical expansion but requiring users to confirm the current text versus prior citations (Background).","Compliance burden (parts, labour, possible downtime) falls on aircraft owners/operators because the AD mandates installation before further flight (Applicability; Compliance).","Potential supply/installation lead times for specific Honeywell parts and certified modification procedures could affect operational availability, though the AD does not specify cost or provisioning mechanisms (Requirement)."],"plain_english_summary":"This directive requires fitting an improved power-turbine retention system and rotor assembly, and an improved electronic power-turbine rotor overspeed controller, to specified Honeywell LTS101 turboshaft engines. It affects owners/operators of LTS101‑650B1, ‑750B1, ‑650C and ‑750C engines because they must install the prescribed hardware and controller before further flight to address reported uncontained turbine failures; Amendment 1 only removes obsolete references and makes editorial changes."},"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"},"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This is Amendment 1 to an existing AD (AD/LTS/13). The amendment makes minor editorial changes and removes obsolete references but does not expand the scope beyond the original safety purpose of preventing power turbine overspeed and uncontained failures. The core mandate remains unchanged."},"complexity_factors":["Short, single-purpose directive with only 2 substantive requirements","Cross-references to 5 specific Honeywell Service Bulletins (SBs) for technical implementation details","Cross-references to 3 other Airworthiness Directives (AD/JBK 117/9, AD/GBK 117/7, AD/BELL 222/19) for airframe wiring requirements","Simple conditional logic: 'unless accomplished previously' exemptions for both requirements","No defined terms section — relies on external technical documents (SBs) for specifications","Clear, tabular format with distinct Applicability, Requirement, Compliance, and Background sections"],"plain_english_summary":"This AD requires operators of helicopters fitted with certain Honeywell LTS101 engines to install a stronger power-turbine retention system and an improved electronic overspeed controller to prevent catastrophic, uncontained turbine failures. It targets aircraft types using these engines (e.g., BK 117, Bo 105, Bell 222) and responds to actual incidents. The mandated upgrades must be completed before the aircraft next flies after the AD takes effect."}},"importantCases":[],"_links":{"self":"/api/acts/ad-lts-13-amdt-1-improved-power-turbine-retention","history":"/api/acts/ad-lts-13-amdt-1-improved-power-turbine-retention/history","analysis":"/api/acts/ad-lts-13-amdt-1-improved-power-turbine-retention/analysis","conflicts":"/api/acts/ad-lts-13-amdt-1-improved-power-turbine-retention/conflicts","importantCases":"/api/acts/ad-lts-13-amdt-1-improved-power-turbine-retention/important-cases","documents":"/api/acts/ad-lts-13-amdt-1-improved-power-turbine-retention/documents"}}