{"id":"F2006B10086","name":"AD/G159/42 - Electrical Power Distribution Protection","slug":"ad-g159-42-electrical-power-distribution-protection","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":55554,"registerId":"commonwealth-F2006B10086-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/G159/42 - Electrical Power Distribution 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 ORDERS CIVIL AVIATION SAFETY AUTHORITY                            PART 105 SCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n![](image.001.png)  GULFSTREAM (GRUMMAN) G.159 SERIES AEROPLANES\n\n \n\nAD/G159/42 Electrical Power Distribution Protection 1/89\n\nApplicability: All models.\n\n \n\nRequirement: Action in accordance with Gulfstream Mandatory Aircraft Service Change No 262. Compliance:               Prior to 26 January 1990.\n\nBackground: In all serial numbers of the G1, the APU generator output sensing wires are routed from the APU to the generator over-voltage protector without any circuit protection. Additionally, in some aircraft, the APU generator feeders themselves do not have circuit protection, and the inverter circuit protection currently provided is insufficient to protect the aircraft. This AD provides fault protection.\n\n \n","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The text contains no statement that the directive expanded or narrowed scope relative to a prior instrument. The AD’s stated applicability is to \"All models\" and the background states the identified wiring/feeder deficiencies across all serial numbers; there is no explicit indication in the text that the scope has changed from an earlier intent."},"complexity_factors":["Refers to a single external technical document (Gulfstream Mandatory Aircraft Service Change No 262) that prescribes the work (Requirement)","Fixed compliance deadline that requires scheduling modifications before 26 January 1990 (Compliance)","Safety‑critical electrical work affecting APU generator sensing wires, generator feeders and inverter protection, requiring qualified maintenance personnel (Background)","Applies to the entire fleet of G.159 models, so aggregate scheduling and resource effects across operators (Applicability)","Some variability in existing aircraft configurations (some already have protection, some do not), creating heterogeneity in scope of work per aircraft (Background)"],"plain_english_summary":"This AD mandates that all Gulfstream G.159 (Grumman) aircraft be modified/inspected per Gulfstream Mandatory Aircraft Service Change No. 262, to be completed before 26 January 1990.  \n\nIt addresses identified electrical‑protection deficiencies (APU generator sensing wiring, some generator feeders, and inverter protection) to provide fault protection. Owners/operators must arrange and fund the work, which requires qualified maintenance and may cause temporary downtime."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, targeted safety directive addressing a specific electrical fault in a specific aircraft type. It has not expanded beyond its original purpose of mandating circuit protection modifications."},"complexity_factors":["Very short document (approximately 150 words)","Only one substantive requirement referencing an external technical document (Gulfstream Mandatory Aircraft Service Change No. 262)","No defined terms section","No cross-references to other legislation or Civil Aviation Orders","Simple conditional structure: applicability → requirement → compliance deadline → background explanation","Single exceptionless mandate with clear deadline"],"plain_english_summary":"This is an **Airworthiness Directive (AD)** — essentially a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA) for aircraft.\n\n**What it does:**\nIt requires owners and operators of **Gulfstream G.159 series aeroplanes** (also known as Grumman G.159s) to carry out specific electrical safety modifications.\n\n**The specific problem:**\nIn these aircraft, the wires that monitor the Auxiliary Power Unit (APU) generator — a small engine that provides power when the main engines are off — were running without any **circuit protection** (like a fuse or circuit breaker that stops dangerous electrical faults). Additionally, some aircraft lacked proper protection for the main APU power cables and the inverter (a device that converts electricity for aircraft systems). This created a fire or electrical failure risk.\n\n**What must be done:**\nOperators must follow **Gulfstream Mandatory Aircraft Service Change No. 262** — a manufacturer-issued repair instruction — to add proper circuit protection.\n\n**Who it affects:**\nAnyone operating a Gulfstream G.159 aircraft in Australia (or Australian-registered aircraft of this type anywhere).\n\n**Why it matters:**\nUnprotected electrical wiring can overheat, cause fires, or fail catastrophically in flight. This directive prevents that by mandating a fix before a deadline of **26 January 1990**.\n\n**Key takeaway:** If you owned one of these planes, you had to get this electrical safety upgrade done by January 1990 or ground the aircraft."}},"importantCases":[],"_links":{"self":"/api/acts/ad-g159-42-electrical-power-distribution-protection","history":"/api/acts/ad-g159-42-electrical-power-distribution-protection/history","analysis":"/api/acts/ad-g159-42-electrical-power-distribution-protection/analysis","conflicts":"/api/acts/ad-g159-42-electrical-power-distribution-protection/conflicts","importantCases":"/api/acts/ad-g159-42-electrical-power-distribution-protection/important-cases","documents":"/api/acts/ad-g159-42-electrical-power-distribution-protection/documents"}}