{"id":"F2006B11174","name":"AD/LTS/11 - Engine Electronic Overspeed Protection System","slug":"ad-lts-11-engine-electronic-overspeed-protection-system","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":56872,"registerId":"commonwealth-F2006B11174-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/LTS/11 - Engine Electronic Overspeed Protection System","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/11 Engine Electronic Overspeed Protection System 8/95\n\nDM\n\nApplicability: AlliedSignal (formerly Textron Lycoming) model LTS101-650B1, -750B1, - 650C3/3A and -750C1 engines incorporating engine electronic overspeed protection systems installed during production prior to 9 May 1995, or retrofitted in accordance with either of the following Textron Lycoming Service Bulletins (SB) or their previous revisions:\n\nLTS101B-73-10-0127 Revision 2 dated 14 August 1992, and\n\nLTS101C-73-10-0129 Revision 3 dated 14 August 1992.\n\nNote: These engines are known to be installed on but not limited to Messerschmitt- Bolkow-Blohm BK117 series and Bell Helicopter Textron 222 series helicopters.\n\nRequirement: 1. Either replace the magnetic speed pickup, part number (PN) 4-301-356-01 in the engine electronic overspeed protection system with a serviceable speed pickup, in accordance with AlliedSignal Engines SB LTS101-73-10-0169 dated 12 December 1994, or inspect the magnetic speed pickup to determine the correct polarity in accordance with the same SB.\n\n    2. If, as a result of the Requirement 1 inspection, the magnetic speed pickup is determined to have the incorrect polarity, replace the pickup with a serviceable speed pickup in accordance with AlliedSignal Engines SB LTS101-73-10-0169 dated 12 December 1994.\n\n    3. Inspect uninstalled magnetic speed pickups PN 4-301-356-01 in accordance with AlliedSignal Engines SB LTS101-73-10-0169 dated 12 December 1994.\n\nNote: FAA AD 95-08-14 Amdt 39-9203 refers.\n\nCompliance: 1. If not previously accomplished, then within 100 hours time in service from 9 June 1995.\n\n    2. Before further flight.\n\n    3. Prior to installation on an engine.\n\nBackground: AlliedSignal has advised that a manufacturing error has resulted in improper sensor polarity of magnetic speed pickups, this could cause the engine electronic overspeed protection system to fail to function as designed. Compliance with this Directive is designed to ensure that the overspeed system operates correctly.","sortOrder":0}],"analysis":{"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"},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The directive confines itself to specified LTS101 engine models with pickups installed before 9 May 1995 or retrofitted under listed service bulletins, and to uninstalled pickups of the same PN (Applicability; Requirement 3). The text contains no provision that expands scope beyond those engines, parts, and retrofit conditions."},"complexity_factors":["Technical specificity of affected engines and exact part number PN 4-301-356-01 (Applicability; Requirement).","Dependence on multiple Textron Lycoming service bulletins for procedures and acceptable revisions (Applicability; Requirement).","Different compliance deadlines tied to distinct triggers: 100 hours from a date, before further flight, and prior to installation (Compliance).","Inspection requires verification of magnetic pickup polarity, which involves technical maintenance judgement and equipment (Requirement 1–2).","Applicability hinges on installation date or prior retrofit status, requiring operators to check maintenance/installation history (Applicability).","Costs and logistics: operators bear inspection/replacement work and parts provisioning (Requirements 1–3).","Cross-reference to FAA AD creates regulatory coordination considerations (Note/Background)."],"plain_english_summary":"This airworthiness directive requires owners/operators of certain AlliedSignal (Lycoming) LTS101 turboshaft engines (those produced before 9 May 1995 or retrofitted per specified service bulletins) to inspect or replace the magnetic speed pickup PN 4-301-356-01 to confirm correct polarity, and to inspect unused pickups before installation. The action responds to a manufacturing error that can reverse sensor polarity and cause the engine electronic overspeed protection to fail; deadlines for replacement/inspection are set in the AD."},"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This Airworthiness Directive maintains its original narrow scope — addressing a specific manufacturing defect in a specific engine series. The applicability criteria, requirements, and compliance deadlines all align with the stated purpose of correcting improper sensor polarity in electronic overspeed protection systems."},"complexity_factors":["Multiple applicability conditions requiring cross-referencing with manufacturer service bulletins (SB LTS101B-73-10-0127, SB LTS101C-73-10-0129)","Three distinct compliance deadlines depending on circumstances (100 hours TIS, before further flight, prior to installation)","Nested conditional logic: Requirement 2 only triggers if Requirement 1 inspection reveals incorrect polarity","Specific part number identification required (PN 4-301-356-01)","Reference to foreign regulatory instrument (FAA AD 95-08-14) for additional context"],"plain_english_summary":"This AD requires owners/operators of AlliedSignal (formerly Lycoming) LTS101-650/750 series turbine engines (notably in MBB BK117 and Bell 222 helicopters) to inspect and, if necessary, replace magnetic speed pickups installed before 9 May 1995 or retrofitted per specified service bulletins. A batch of pickups had reversed polarity, which can disable the electronic overspeed protection.\n\nCompliance is required within 100 flight hours (immediate grounding if wrong polarity is found) and spares must be checked before installation to prevent catastrophic engine overspeed."}},"importantCases":[],"_links":{"self":"/api/acts/ad-lts-11-engine-electronic-overspeed-protection-system","history":"/api/acts/ad-lts-11-engine-electronic-overspeed-protection-system/history","analysis":"/api/acts/ad-lts-11-engine-electronic-overspeed-protection-system/analysis","conflicts":"/api/acts/ad-lts-11-engine-electronic-overspeed-protection-system/conflicts","importantCases":"/api/acts/ad-lts-11-engine-electronic-overspeed-protection-system/important-cases","documents":"/api/acts/ad-lts-11-engine-electronic-overspeed-protection-system/documents"}}