{"id":"F2006B10084","name":"AD/G159/40 - Main and Nose Landing Gear Uplock Cylinder Attach Bolts - Replacement","slug":"ad-g159-40-main-and-nose-landing-gear-uplock-cylinder-attach-bolts-replacement","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":55547,"registerId":"commonwealth-F2006B10084-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/G159/40 - Main and Nose Landing Gear Uplock Cylinder Attach Bolts - Replacement","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/G159/40 Main and Nose Landing Gear Uplock Cylinder Attach\n\nBolts - Replacement\n\nApplicability: All models G159-1, -1C and -TC4C.\n\n \n\nDocument: Gulfstream American Customer Bulletin No. 285A.\n\n# 5/82\n\n \n\nCompliance: Unless already accomplished, within 100 hours time in service after 31 May 1982.\n\n \n\nBackground: Loss of a main landing gear uplock cylinder attach bolt has resulted in a gear up\n\nlanding involving an overseas aeroplane.\n\n \n","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, single-issue safety directive focused specifically on bolt replacement for landing gear uplock cylinders. It has not expanded beyond its original narrow technical purpose."},"complexity_factors":["Extremely short document (under 200 words)","Only 4 operative provisions: applicability, reference document, compliance deadline, and background","No defined terms section","No cross-references to other legislation","Single, unambiguous compliance action (bolt replacement)","No conditional logic or exceptions"],"plain_english_summary":"**What this is:** This is an **Airworthiness Directive (AD)** — a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA). Think of it as a \"recall notice\" for aircraft, but legally binding.\n\n**What it requires:** Owners and operators of specific Gulfstream G.159 series aeroplanes must **replace certain bolts** on the main and nose landing gear \"uplock cylinders\" (the hydraulic mechanisms that hold the wheels up when the plane is flying).\n\n**Which planes are affected:** All Gulfstream G.159-1, G.159-1C, and G.159-TC4C models.\n\n**The safety problem:** A bolt holding the main landing gear uplock cylinder had fallen out on an overseas aircraft, causing the landing gear to collapse unexpectedly during landing (a \"gear up landing\" — where the wheels don't come down). This could cause serious damage and injury.\n\n**When it had to be done:** Within 100 hours of flying time after 31 May 1982 (unless already fixed).\n\n**Why it matters:** This directive prevents catastrophic landing gear failure. The bolt replacement is relatively simple maintenance that avoids potentially fatal accidents during landing."},"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"The AD's scope aligns with its stated intent: it targets replacement of uplock cylinder attach bolts on the specified G.159 models because a lost bolt caused a gear-up landing (Background). The instrument specifies who must act (operators of the listed models), what to do (replace the bolts using Gulfstream Customer Bulletin No. 285A), and when to do it (within 100 hours TIS after 31 May 1982) (Applicability; Document; Compliance). There is no indication in the text that the scope departs from that stated purpose."},"complexity_factors":["Narrow applicability: applies only to G159-1, -1C and -TC4C models (Applicability).","Single specified action: replace main and nose landing gear uplock cylinder attach bolts (Title and Document).","Fixed, short compliance window: within 100 hours time in service after 31 May 1982 (Compliance).","Dependence on an external procedural reference (Gulfstream Customer Bulletin No. 285A) rather than detailed steps in the AD text (Document).","Safety-critical consequence if not complied with (Background), increasing operational urgency despite procedural simplicity."],"plain_english_summary":"This AD requires operators of Gulfstream (Grumman) G.159 series aeroplanes (G159-1, -1C, -TC4C) to replace the main and nose landing gear uplock cylinder attach bolts using Gulfstream American Customer Bulletin No. 285A, to be completed within 100 hours’ time in service after 31 May 1982. It was issued to prevent recurrence of a bolt loss that led to an overseas gear‑up landing; operators must arrange and pay for the maintenance, scheduling work with authorised providers within the compliance window."}},"importantCases":[],"_links":{"self":"/api/acts/ad-g159-40-main-and-nose-landing-gear-uplock-cylinder-attach-bolts-replacement","history":"/api/acts/ad-g159-40-main-and-nose-landing-gear-uplock-cylinder-attach-bolts-replacement/history","analysis":"/api/acts/ad-g159-40-main-and-nose-landing-gear-uplock-cylinder-attach-bolts-replacement/analysis","conflicts":"/api/acts/ad-g159-40-main-and-nose-landing-gear-uplock-cylinder-attach-bolts-replacement/conflicts","importantCases":"/api/acts/ad-g159-40-main-and-nose-landing-gear-uplock-cylinder-attach-bolts-replacement/important-cases","documents":"/api/acts/ad-g159-40-main-and-nose-landing-gear-uplock-cylinder-attach-bolts-replacement/documents"}}