{"id":"F2006B10020","name":"AD/G1159/19 - Landing Gear and Oxygen Systems Gas Cylinders - Inspection and Replacement","slug":"ad-g1159-19-landing-gear-and-oxygen-systems-gas-cylinders-inspection-and-replacement","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":55403,"registerId":"commonwealth-F2006B10020-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/G1159/19 - Landing Gear and Oxygen Systems Gas Cylinders - Inspection and 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 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/G1159/19 Landing Gear and Oxygen Systems Gas\n\nCylinders - Inspection and Replacement\n\nApplicability: All models with gas cylinders listed in requirement document. Document: 1. Grumman CB No. 211; or\n\n2. FAA AD 75-22-22 Amendment 39-2409.\n\n \n\nCompliance: Within 100 hours time in service after 31 March 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\n4/76\n","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The text supplied states a single, time‑limited requirement that applies to all G1159 and G‑IV series aeroplanes that have the gas cylinders listed in the referenced documents, with compliance due within 100 hours TIS after 31 March 1975. There is no indication in the supplied text that the instrument’s scope was altered from an earlier version; the AD as provided sets the applicability, the technical reference documents, and the compliance deadline without evidencing a change in scope."},"complexity_factors":["Instruction is short and prescriptive: a single required action (inspect/replace) with a clear deadline (low intrinsic legal complexity). (Compliance)","Relies on two external technical documents (Grumman CB No. 211 and FAA AD 75‑22‑22) for procedural detail, which increases compliance complexity for operators who must obtain and apply those documents. (Document)","Applicability is conditional on listed cylinders rather than every aircraft of the model, which requires operators to check equipment fit to determine whether they are affected. (Applicability)","Operational complexity from the 100‑hour time window after a fixed calendar date creates scheduling and resource‑allocation issues for maintenance providers. (Compliance)","No part numbers, procedures or replacement approvals are recited in the AD text itself, creating dependence on external technical material and maintenance judgement. (Document)"],"plain_english_summary":"This directive requires operators of Gulfstream (Grumman) G1159 and G‑IV aeroplanes that have specified gas cylinders to inspect—and, if indicated by the referenced documents, replace—cylinders used in landing‑gear and oxygen systems. Compliance is by following Grumman CB No. 211 or FAA AD 75‑22‑22 within 100 hours time‑in‑service after 31 March 1975. It affects aircraft owners/operators, creating airworthiness, cost and scheduling obligations."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a historical Airworthiness Directive from 1976 (reference '4/76' indicates April 1976). The scope remains precisely targeted at the specific safety issue identified in the referenced Grumman service bulletin and FAA directive. There is no evidence of scope creep; it addresses exactly what it was issued for — gas cylinder inspection and replacement on specific Gulfstream models."},"complexity_factors":["Very short document (approximately 200 words)","Only 3 defined elements: applicability, document references, and compliance deadline","No nested conditional logic or exceptions","No cross-references to other legislation beyond two external technical documents","Single, clear compliance action with unambiguous deadline","Standardised AD format following CASA template"],"plain_english_summary":"This is an **Airworthiness Directive (AD)** — a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA). It requires owners and operators of specific Gulfstream business jets (the G1159 and G-IV series) to inspect and replace certain gas cylinders used in the landing gear and oxygen systems.\n\n**Who it affects:**\n- Owners and operators of Gulfstream (formerly Grumman) G1159 and G-IV series aircraft\n- Maintenance organisations servicing these aircraft\n\n**What it requires:**\n- Inspection and replacement of gas cylinders listed in the referenced technical documents (Grumman Service Bulletin No. 211 or the equivalent US FAA directive)\n- This work must be completed within **100 hours of flight time** after 31 March 1975\n\n**Why it matters:**\nAirworthiness Directives are legally binding safety instructions. They are issued when a safety defect is found that could affect flight safety. Non-compliance means the aircraft cannot legally fly in Australian airspace. This particular directive addresses potential failures in gas cylinders that could affect emergency oxygen supply or landing gear operation — critical systems for passenger safety and aircraft control."}},"importantCases":[],"_links":{"self":"/api/acts/ad-g1159-19-landing-gear-and-oxygen-systems-gas-cylinders-inspection-and-replacement","history":"/api/acts/ad-g1159-19-landing-gear-and-oxygen-systems-gas-cylinders-inspection-and-replacement/history","analysis":"/api/acts/ad-g1159-19-landing-gear-and-oxygen-systems-gas-cylinders-inspection-and-replacement/analysis","conflicts":"/api/acts/ad-g1159-19-landing-gear-and-oxygen-systems-gas-cylinders-inspection-and-replacement/conflicts","importantCases":"/api/acts/ad-g1159-19-landing-gear-and-oxygen-systems-gas-cylinders-inspection-and-replacement/important-cases","documents":"/api/acts/ad-g1159-19-landing-gear-and-oxygen-systems-gas-cylinders-inspection-and-replacement/documents"}}