{"id":"F2006B10054","name":"AD/G159/10 - Installation of Accessory Gearbox Generator Baffle and Supercharger Drain Line","slug":"ad-g159-10-installation-of-accessory-gearbox-generator-baffle-and-supercharger-drain-line","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":55498,"registerId":"commonwealth-F2006B10054-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/G159/10 - Installation of Accessory Gearbox Generator Baffle and Supercharger Drain Line","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\n# AD/G159/10 Installation of Accessory Gearbox Generator Baffle\n\nand Supercharger Drain Line\n\nApplicability: All models with S/Nos. 1 to 12, 14 to 86 and 114. Document:  Grumman Service Change No. 139.\n\n# 4/67\n\nNote: Installation of the baffle between the DC generator and the generator adapter as called up in Part 1 of the above Service Change need not be carried out if Dowty Rotol Modification GB1843 is incorporated.\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\n \n","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The instrument, as presented, sets out a specific required modification for identified serial-numbered aircraft and names the technical document to be followed, with a single conditional exemption. The text does not indicate any change from an earlier scope or intent; it states applicability, the required service document, and the exemption (Applicability; Document; Note)."},"complexity_factors":["Narrow applicability by serial number (S/Nos. 1–12, 14–86 and 114) — requires operators to check individual aircraft identity (Applicability).","Dependence on an external technical document for detailed instructions (Grumman Service Change No. 139) — the AD delegates procedural detail to that service publication (Document).","Single conditional exemption based on prior incorporation of Dowty Rotol Modification GB1843 — requires verification of prior modification to determine scope of required work (Note).","Mechanical installation tasks (baffle and drain line) that require certified maintenance personnel and parts — creates operational scheduling and parts-sourcing burdens.","Limited textual complexity but practical implementation involves coordination between operators and maintenance organisations and accurate record-keeping."],"plain_english_summary":"What this instrument does\n\n- Requires installation of two specific physical modifications on certain Gulfstream (Grumman) G.159 aeroplanes: an accessory gearbox generator baffle and a supercharger drain line (title: AD/G159/10 “Installation of Accessory Gearbox Generator Baffle and Supercharger Drain Line”).\n- Identifies the affected aeroplanes by serial number: all models with S/Nos. 1 to 12, 14 to 86 and 114 (stated under “Applicability”).\n- Specifies the work to be done by referring maintenance personnel to the manufacturer’s service instruction: Grumman Service Change No. 139 (listed as “Document: Grumman Service Change No. 139”).\n\nWho this affects and who decides\n\n- Aircraft owners/operators of Gulfstream G.159 aeroplanes with the listed serial numbers must ensure the modifications are installed on their aircraft (the instrument’s applicability statement identifies the set of affected aircraft). \n- Licensed maintenance organisations and engineers will carry out the physical installations according to the referenced service change. \n- The Civil Aviation authority issues the directive; compliance is an operational/legal obligation on the operator for the affected aeroplanes.\n\nHow it works mechanically\n\n- The directive takes the manufacturer’s Service Change No. 139 as the technical instruction for how to install the accessory gearbox generator baffle and the supercharger drain line. Operators must follow that service material to complete the installation.\n- There is an explicit conditional exemption for one part of the work: if Dowty Rotol Modification GB1843 has already been incorporated, then installation of the baffle between the DC generator and the generator adapter (Part 1 of the Service Change) is not required (see the Note: “Installation of the baffle ... need not be carried out if Dowty Rotol Modification GB1843 is incorporated”).\n\nWho pays and what changes in behaviour\n\n- Costs for parts, labour, and any aircraft downtime fall on the aircraft owners/operators. \n- Maintenance providers receive and schedule the work; operators must plan for the aircraft to be taken into maintenance for the modification. \n- Where the Dowty Rotol modification is already present, operators avoid that specific installation and therefore save the associated time and cost.\n\nImplementation, compliance and decision points (concrete mechanics)\n\n- The directive points to a specific manufacturer service change as the required technical procedure; compliance requires maintenance records and certification that the work was carried out in accordance with that document (reference: “Document: Grumman Service Change No. 139”).\n- The exemption for operators who already have Dowty Rotol Modification GB1843 incorporated creates a clear decision point: verify modification status before carrying out Part 1 of the Service Change (reference: the Note). \n- Practical implementation costs include sourcing parts called for by the Service Change, booking certified maintenance time, and documenting compliance.\n\nTrade-offs, incentives and risks (procedural and economic)\n\n- Operators trade immediate outlays (parts, labour, downtime) for regulatory compliance. \n- Maintenance organisations have an incentive to perform the work; aircraft owners have an incentive to confirm whether modification GB1843 is fitted to avoid duplicative work. \n- Risks include installation errors if the Service Change is not followed precisely and administrative risk if compliance is not properly recorded. The instrument itself does not quantify costs or specify deadlines; it identifies affected aircraft, the technical document to follow, and an explicit conditional exemption (Applicability; Document; Note)."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, targeted safety directive focused on a specific mechanical modification for a narrow subset of aircraft. It has not expanded beyond its original purpose of mandating a particular airworthiness fix."},"complexity_factors":["Extremely short document (approximately 150 words)","Only 1 defined term implicitly referenced (the Service Change document)","Single conditional exception (the Dowty Rotol modification exemption)","No cross-references to other legislation or regulations","Simple binary applicability test (serial number ranges)","No nested conditions or layered exceptions"],"plain_english_summary":"This is an **Airworthiness Directive (AD)** — a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA). It requires specific modifications to certain Gulfstream G.159 aeroplanes (a type of aircraft).\n\n**What it does:**\n- Requires owners/operators to install a **baffle** (a protective shield) between the DC generator and its adapter, and to install a **supercharger drain line** (a pipe to remove fluids from the supercharger — a device that forces extra air into the engine for more power).\n- These changes are detailed in **Grumman Service Change No. 139**.\n\n**Who it affects:**\n- All Gulfstream G.159 aircraft with **serial numbers 1–12, 14–86, and 114**.\n\n**The exception:**\n- You **don't** need to install the generator baffle **if** your aircraft already has **Dowty Rotol Modification GB1843** installed. This is an alternative fix that achieves the same safety outcome.\n\n**Why it matters:**\nAirworthiness Directives are legally binding. If you don't comply, you cannot fly the aircraft. This particular AD addresses potential safety issues with the generator and supercharger systems — likely fire hazards, oil leaks, or mechanical failures that could endanger flight safety."}},"importantCases":[],"_links":{"self":"/api/acts/ad-g159-10-installation-of-accessory-gearbox-generator-baffle-and-supercharger-drain-line","history":"/api/acts/ad-g159-10-installation-of-accessory-gearbox-generator-baffle-and-supercharger-drain-line/history","analysis":"/api/acts/ad-g159-10-installation-of-accessory-gearbox-generator-baffle-and-supercharger-drain-line/analysis","conflicts":"/api/acts/ad-g159-10-installation-of-accessory-gearbox-generator-baffle-and-supercharger-drain-line/conflicts","importantCases":"/api/acts/ad-g159-10-installation-of-accessory-gearbox-generator-baffle-and-supercharger-drain-line/important-cases","documents":"/api/acts/ad-g159-10-installation-of-accessory-gearbox-generator-baffle-and-supercharger-drain-line/documents"}}