{"id":"F2006B10899","name":"AD/JETSTREAM/31 - Inverter Circuit Protection","slug":"ad-jetstream-31-inverter-circuit-protection","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":56435,"registerId":"commonwealth-F2006B10899-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/JETSTREAM/31 - Inverter Circuit Protection","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\nAD/JETSTREAM/31 Inverter Circuit Protection 1/89\n\nApplicability: All Jetstream 3100 series aircraft constructors numbers 696 to 794, 796 to 799, 801 to\n\n804, 806 to 809, 811 to 813, 815 to 817, and 820.\n\n \n\nRequirement: Action in accordance with BAe ASB 24-A-JA7672A. Compliance:  Prior to 26 April 1989.\n\nBackground: BAe have advised that the 26 Vac output cable of AII inverters installed by modification JM 7518 are not protected by a thermal fuse or circuit breaker. ASB 24- A-JA 7672A installs circuit breaker protection for the 26 Vac output cable.\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\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":{"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The AD's scope is confined to the specified Jetstream 3100 constructor numbers and to the single corrective action described (installation of circuit breaker protection for the 26 Vac output cable of AII inverters installed by modification JM 7518). The instrument does not expand to other aircraft types, other systems, or other modifications; it instead mandates performance of BAe ASB 24‑A‑JA7672A by the listed operators before 26 April 1989. (Applicability, Requirement, Compliance, Background)"},"complexity_factors":["Narrow, specific applicability limited to listed constructor numbers (Applicability)","Single, targeted technical remedy rather than multiple, interlocking changes (Requirement, Background)","Reliance on an external technical document (BAe ASB 24‑A‑JA7672A) for the required technical steps (Requirement)","Safety‑critical electrical work which requires qualified personnel and aircraft downtime (Background, Requirement)","Hard compliance deadline (Compliance) that concentrates scheduling and operational impact"],"plain_english_summary":"This AD mandates installation of a circuit breaker on the 26 Vac output cable of the AII inverter on specified BAe Jetstream 3100 constructor‑number aircraft, to be done per BAe ASB 24‑A‑JA7672A. Affected operators must complete the work before 26 April 1989; owners/operators bear the cost. The measure corrects the lack of over‑current protection identified by BAe and reduces electrical‑fire/fault risk on the listed aeroplanes."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, time-bound safety directive with a narrow, well-defined scope addressing a specific electrical hazard in specific aircraft. It has not expanded beyond its original purpose."},"complexity_factors":["Single, specific technical requirement with no conditional logic","Only one defined applicability criterion (specific aircraft serial numbers)","No cross-references to other legislation or regulations beyond the parent Civil Aviation Regulations 1998","Clear, fixed compliance deadline (prior to 26 April 1989)","No exceptions, exemptions, or alternative means of compliance described","Short document (approximately 150 words of substantive content)"],"plain_english_summary":"This is an **Airworthiness Directive (AD)** — essentially a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA) for specific aircraft.\n\n**What it does:**\nOrders owners and operators of certain British Aerospace Jetstream 3100 series planes to install circuit breaker protection on a specific electrical cable. The cable in question carries 26 volts of alternating current (Vac) from the aircraft's inverter (a device that converts DC power to AC power).\n\n**Who it affects:**\nOwners and operators of Jetstream 3100 aircraft with specific serial numbers (constructors numbers 696-794, 796-799, 801-804, 806-809, 811-813, 815-817, and 820). These are regional turboprop aircraft commonly used for passenger and freight services.\n\n**Why it matters:**\nWithout circuit breaker protection, the electrical cable could overheat and cause a fire. British Aerospace discovered that a particular modification (JM 7518) had installed inverters without proper thermal protection on this output cable. The directive requires compliance with a specific British Aerospace Alert Service Bulletin (ASB 24-A-JA7672A) before 26 April 1989.\n\n**Key terms explained:**\n- **Airworthiness Directive (AD):** A legally enforceable safety order that must be followed to keep an aircraft certified as airworthy (safe to fly).\n- **Inverter:** An electrical device that converts direct current (DC) to alternating current (AC).\n- **ASB (Alert Service Bulletin):** An urgent manufacturer notice describing a safety-related modification or inspection.\n- **Thermal fuse/circuit breaker:** Safety devices that cut off electrical flow if overheating occurs."}},"importantCases":[],"_links":{"self":"/api/acts/ad-jetstream-31-inverter-circuit-protection","history":"/api/acts/ad-jetstream-31-inverter-circuit-protection/history","analysis":"/api/acts/ad-jetstream-31-inverter-circuit-protection/analysis","conflicts":"/api/acts/ad-jetstream-31-inverter-circuit-protection/conflicts","importantCases":"/api/acts/ad-jetstream-31-inverter-circuit-protection/important-cases","documents":"/api/acts/ad-jetstream-31-inverter-circuit-protection/documents"}}