{"id":"F2006B10071","name":"AD/G159/27 - Landing Gear and Oxygen Systems Gas Cylinders - Inspection and Replacement","slug":"ad-g159-27-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":55516,"registerId":"commonwealth-F2006B10071-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/G159/27 - 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 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/G159/27 Landing Gear and Oxygen Systems Gas Cylinders -\n\nInspection and Replacement Applicability: All models with gas cylinders listed in the requirement documents. Document:              1. Grumman Customer Bulletin No. 282; or\n\n2. FAA AD 75-22-22 Amdt. 39-2409.\n\n \n\nCompliance: Within 100 hours time in service after 31 March 1975.\n\n\n4/76\n","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The text does not indicate any change to the directive’s scope from an earlier or original instrument. It applies to all G.159 models that contain the gas cylinders listed in the referenced documents and requires compliance within the stated 100-hour time window. The directive delegates technical detail to the named Grumman and FAA documents (Applicability, Document, Compliance)."},"complexity_factors":["Directive text is short and procedural, so baseline complexity is low.","Key technical requirements are externalised to two referenced documents (Grumman Customer Bulletin No. 282; FAA AD 75-22-22 Amdt. 39-2409), requiring users to obtain and follow those documents (Document).","Applicability is categorical but depends on whether an aeroplane contains the \"listed\" cylinders, which requires cross-referencing the external material to determine coverage (Applicability, Document).","Fixed historic compliance window (100 hours after 31 March 1975) requires tracking of flight hours and scheduling within a limited period (Compliance).","The AD itself does not set the technical inspection criteria or replacement thresholds, creating implementation reliance on external authorities (Document)."],"plain_english_summary":"This AD requires owners/operators of Gulfstream (Grumman) G.159 aeroplanes to inspect—and, if the referenced Grumman Customer Bulletin No. 282 or FAA AD 75‑22‑22 directs, replace—certain gas cylinders used in the landing‑gear and oxygen systems.  \n\nCompliance was mandatory within 100 flight hours after 31 March 1975, costs and downtime fall to the owner/operator, and conformity is demonstrated only by following the specified technical documents."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, single-issue airworthiness directive from 1976 addressing a specific safety defect in a specific aircraft type. It has not expanded beyond its original narrow scope of gas cylinder inspection and replacement for Gulfstream G.159 aircraft."},"complexity_factors":["Extremely short document — only 4 substantive lines of regulatory text","No defined terms section — relies entirely on external technical documents","Simple, single-layer compliance requirement with clear deadline","No conditional logic, exceptions, or nested provisions","Cross-references only to external technical documents (manufacturer bulletin and FAA directive), not to other legislative provisions"],"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 **Gulfstream G.159 series aircraft** to inspect and replace certain gas cylinders used in the landing gear and oxygen systems.\n\n**What it does:**\n- Mandates specific safety inspections and replacements for gas cylinders on these aircraft\n- References technical documents from the manufacturer (Grumman Customer Bulletin No. 282) and the US aviation regulator (FAA AD 75-22-22)\n\n**Who it affects:**\n- Owners and operators of all Gulfstream (Grumman) G.159 series aeroplanes that have the specific gas cylinders mentioned in the technical documents\n\n**Why it matters:**\n- Gas cylinder failures in landing gear or oxygen systems can cause catastrophic safety failures — landing gear collapse or loss of emergency oxygen supply\n- The directive sets a hard deadline: compliance required within **100 hours of flight time** after 31 March 1975\n- Non-compliance means the aircraft cannot legally fly in Australian airspace\n\n**Key point:** This is not optional maintenance advice — it's a legal requirement. If you don't comply, your aircraft is grounded."}},"importantCases":[],"_links":{"self":"/api/acts/ad-g159-27-landing-gear-and-oxygen-systems-gas-cylinders-inspection-and-replacement","history":"/api/acts/ad-g159-27-landing-gear-and-oxygen-systems-gas-cylinders-inspection-and-replacement/history","analysis":"/api/acts/ad-g159-27-landing-gear-and-oxygen-systems-gas-cylinders-inspection-and-replacement/analysis","conflicts":"/api/acts/ad-g159-27-landing-gear-and-oxygen-systems-gas-cylinders-inspection-and-replacement/conflicts","importantCases":"/api/acts/ad-g159-27-landing-gear-and-oxygen-systems-gas-cylinders-inspection-and-replacement/important-cases","documents":"/api/acts/ad-g159-27-landing-gear-and-oxygen-systems-gas-cylinders-inspection-and-replacement/documents"}}