{"id":"F2006B10019","name":"AD/G1159/18 - Ground Spoiler System - Deactivation","slug":"ad-g1159-18-ground-spoiler-system-deactivation","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":55400,"registerId":"commonwealth-F2006B10019-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/G1159/18 - Ground Spoiler System - Deactivation","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)  Gulfstream (Grumman) G1159 and G-IV Series Aeroplanes\n\n \n\nAD/G1159/18 Ground Spoiler System - Deactivation 12/75\n\nApplicability: All models not modified in accordance with Grumman Aircraft Service Change No.\n\n180.\n\n \n\nDocument: FAA AD 74-17-05 Amendment 39-2359.\n\n \n\nCompliance: Within 10 hours time in service after 18 November 1975.\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\n \n\n \n","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The instrument's stated scope is limited to \"All models not modified in accordance with Grumman Aircraft Service Change No. 180.\" The text provided shows no indication that the instrument's scope has been expanded or reduced from that stated applicability; it simply requires deactivation for aircraft within that defined group and sets a compliance deadline."},"complexity_factors":["Narrow technical subject matter limited to a specific aircraft system (ground spoilers) and models","Short, strict compliance timeframe (10 hours time in service) creating operational urgency","Applicability carved out by reference to an external modification (Grumman Service Change No. 180)","Directive cross‑references an external regulator's document (FAA AD 74-17-05) for technical detail","Absence of procedural detail in the instrument increases implementation uncertainty for maintenance providers"],"plain_english_summary":"This AD requires owners/operators of Gulfstream (Grumman) G1159 and G‑IV series aeroplanes to deactivate the aircraft ground‑spoiler system unless the aeroplane already has Grumman Service Change No. 180 installed. Compliance was mandatory within 10 hours time‑in‑service after 18 November 1975 and the directive relies on FAA AD 74‑17‑05 as its technical source."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, single-issue safety directive from 1975 addressing a specific mechanical defect in a specific aircraft type. It has not expanded beyond its original purpose of grounding the spoiler system pending proper modification."},"complexity_factors":["Extremely short document — approximately 150 words total","Only 4 operative provisions: applicability, document reference, compliance deadline, and the implicit requirement to deactivate the system","Single condition in applicability (unmodified aircraft per Service Change No. 180)","No defined terms section — relies entirely on external references (FAA AD 74-17-05)","No nested exceptions, conditional logic, or cross-references to other Australian legislation","Straightforward command structure: identify affected aircraft, cite source document, set deadline"],"plain_english_summary":"**What this is:** This is an **Airworthiness Directive (AD)** — essentially a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA). Think of it like a compulsory recall notice, but for aircraft rather than cars.\n\n**What it does:** It requires owners and operators of specific Gulfstream business jets (the G1159 and G-IV series) to **deactivate (turn off) the ground spoiler system** on their aircraft.\n\n**Who it affects:** Anyone operating Gulfstream G1159 or G-IV series aeroplanes that **haven't** been modified according to \"Grumman Aircraft Service Change No. 180\" — basically, older models without a specific factory fix.\n\n**Why it matters:** Ground spoilers are panels on the wings that pop up after landing to kill lift and help the plane slow down. If this system is faulty, it could cause dangerous problems during landing — potentially loss of control or runway excursions. The FAA (American aviation regulator) found this issue first, and Australia adopted their safety directive.\n\n**The deadline:** Operators had to comply within **10 hours of flying time** after 18 November 1975 — meaning this was an urgent, immediate safety fix, not something you could postpone.\n\n**Key takeaway:** If you were flying one of these Gulfstreams in late 1975, you had to disable this system quickly or risk your aircraft being grounded (or worse, having an accident)."}},"importantCases":[],"_links":{"self":"/api/acts/ad-g1159-18-ground-spoiler-system-deactivation","history":"/api/acts/ad-g1159-18-ground-spoiler-system-deactivation/history","analysis":"/api/acts/ad-g1159-18-ground-spoiler-system-deactivation/analysis","conflicts":"/api/acts/ad-g1159-18-ground-spoiler-system-deactivation/conflicts","importantCases":"/api/acts/ad-g1159-18-ground-spoiler-system-deactivation/important-cases","documents":"/api/acts/ad-g1159-18-ground-spoiler-system-deactivation/documents"}}