{"id":"F2006B10907","name":"AD/JETSTREAM/39 - Introduction Of Inverter Part No. 1B350-1B1-3 (Modification Jm 7740)","slug":"ad-jetstream-39-introduction-of-inverter-part-no-1b350-1b1-3-modification-jm-7740","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":56445,"registerId":"commonwealth-F2006B10907-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/JETSTREAM/39 - Introduction Of Inverter Part No. 1B350-1B1-3 (Modification Jm 7740)","content":"---\nmeta-content-style-type: text/css\nmeta-content-type: application/xhtml+xml; charset=utf-8\nmeta-generator: Aspose.Words for .NET 22.10.0\n---\n\n?xml version=\"1.0\" encoding=\"utf-8\" standalone=\"no\"?>\n\nCOMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n \n\n![](image.001.png)  British Aerospace BAe 3100 (Jetstream) Series Aeroplanes\n\n \n\n# AD/JETSTREAM/39 Introduction Of Inverter Part No.\n\n1B350-1B1-3 (Modification Jm 7740)\n\nApplicability: All Jetstream aircraft detailed in the Requirement Document. Requirement: Action in accordance with BAe SB 24-JM 7740.\n\nNote 1: Compliance with this SB is considered mandatory by the CAA (UK).\n\n# 3/91\n\n \n\nNote 2: Accomplishment of modification JM 7740 (Mandatory SB 24-JM 7740) in accordance with this AD does not remove the necessity to comply with the emergency procedures of the flight manual amendment introduced by Mandatory Alert SB 24-A- JA 900443 (refer AD/JETSTREAM/38, Requirement 1). The Flight Manual emergency procedures are revised only after the accomplishment of both Mandatory SB 24-JM 7740 and optional SB 24-JA 900941.\n\n \n\nCompliance: As specified in the Requirement Document.\n\n \n\nBackground:  BAe have advised that investigations into recent AC power instability problems have been concluded, and the cause has been determined to be inadequate protection within the part no 1B350-1B1-2 inverters. This AD mandates compliance with BAe Mandatory SB 24-JM 7740, and advises that compliance with optional SB 24-JA 900941 as well as with SB 24-JM 7740 will allow the transfer function deleted by Alert 3/91SB 24-JA 900443 R1 (refer AD/JETSTREAM/38, Requirement 1) to be reinstated.\n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This is a discrete, targeted safety directive addressing a specific identified defect in a specific aircraft component. The scope remains tightly focused on the inverter replacement requirement as originally intended. The reference to optional additional work (SB 24-JA 900941) does not expand the mandatory scope but provides context for future relief from emergency procedures."},"complexity_factors":["Short, single-purpose directive (approximately 250 words)","Only 2 defined document references (SB 24-JM 7740 and SB 24-JA 900941)","Simple conditional logic: mandatory action required, with optional additional action noted","Heavy reliance on external technical documents (the 'Requirement Document' and service bulletins) without reproducing their contents","Cross-reference to related directive AD/JETSTREAM/38 for context","Technical aviation terminology assumes operator familiarity (inverters, service bulletins, transfer functions)"],"plain_english_summary":"This CASA Airworthiness Directive mandates that operators of British Aerospace Jetstream 3100 series replace/modify the inverter P/N 1B350-1B1-2 with P/N 1B350-1B1-3 per manufacturer service bulletin SB 24-JM 7740. The older inverters lack adequate electrical protection, causing AC power instability in flight, so the change is compulsory to address the safety risk. Emergency procedures from a prior AD remain until an additional, optional modification is also done."},"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":true,"description":"This AD expands remedial obligations by mandating modification JM 7740 (installation of inverter part 1B350-1B1-3) for Jetstream aeroplanes (Requirement; Applicability). It does not remove prior flight‑manual emergency procedure requirements introduced by earlier Alert SBs, and reinstatement of a deleted transfer function is conditional on completing an optional SB as well (Note 2; Background)."},"complexity_factors":["Cross-reference to external documents: Requirement Document controls applicability and compliance timing, not spelled out in the AD (Applicability; Compliance).","Multiple service bulletins involved: Mandatory SB 24-JM 7740, optional SB 24-JA 900941, and prior Alert SB 24-JA 900443 interact (Requirement; Note 2; Background).","Technical specificity limited in-text: only part numbers and SB references are given, so technical execution depends on the referenced SB content (Requirement).","Regulatory attribution: AD cites the CAA (UK) treating the SB as mandatory, introducing multi-jurisdictional enforcement context (Note 1).","Operational dependency: flight manual emergency procedures remain required until both mandatory and optional SBs are addressed, creating sequencing constraints (Note 2)."],"plain_english_summary":"This Airworthiness Directive requires fitting BAe inverter part no. 1B350-1B1-3 to the Jetstream aeroplanes listed in the Requirement Document by carrying out BAe Mandatory SB 24-JM 7740 (Applicability; Requirement; Note 1). It is issued because investigations tied recent AC power instability to inadequate protection in inverter part 1B350-1B1-2 (Background). Operators must perform the modification as specified (Compliance), bear the cost and operational work, and note reinstating a deleted transfer function needs an optional SB plus the flight‑manual amendment (Note 2)."}},"importantCases":[],"_links":{"self":"/api/acts/ad-jetstream-39-introduction-of-inverter-part-no-1b350-1b1-3-modification-jm-7740","history":"/api/acts/ad-jetstream-39-introduction-of-inverter-part-no-1b350-1b1-3-modification-jm-7740/history","analysis":"/api/acts/ad-jetstream-39-introduction-of-inverter-part-no-1b350-1b1-3-modification-jm-7740/analysis","conflicts":"/api/acts/ad-jetstream-39-introduction-of-inverter-part-no-1b350-1b1-3-modification-jm-7740/conflicts","importantCases":"/api/acts/ad-jetstream-39-introduction-of-inverter-part-no-1b350-1b1-3-modification-jm-7740/important-cases","documents":"/api/acts/ad-jetstream-39-introduction-of-inverter-part-no-1b350-1b1-3-modification-jm-7740/documents"}}