{"id":"F2006B10026","name":"AD/G1159/24 Amdt 2 - Cabin Pressure Differential - Restriction","slug":"ad-g1159-24-amdt-2-cabin-pressure-differential-restriction","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":55418,"registerId":"commonwealth-F2006B10026-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/G1159/24 Amdt 2 - Cabin Pressure Differential - Restriction","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/G1159/24\n\nAmdt 2\n\n\nCabin Pressure Differential - Restriction 12/78\n\n \n\nApplicability: All models with S/Nos. 001 to 229 and 775. Document:  1. Grumman Customer Bulletin No. 270A; or\n\n2. FAA AD 78-14-06 Amendment 39-3313.\n\n \n\nCompliance: As per requirement document No. 1.\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":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This appears to be a straightforward amendment (Amdt 2) to an existing Airworthiness Directive. The scope remains tightly focused on the original safety issue regarding cabin pressure differential restrictions for specific Gulfstream aircraft serial numbers. There is no evidence of scope creep — the document maintains its original narrow technical purpose of addressing a specific airframe limitation."},"complexity_factors":["Extremely short document — essentially a reference pointer to external technical documents","Only 2 defined applicability criteria (aircraft models and serial numbers)","No conditional logic or nested exceptions within the directive itself","Compliance achieved by reference to external technical bulletin rather than detailed instructions in the text","Minimal cross-referencing — only points to 2 external documents (Grumman bulletin and FAA AD)","No interpretation section or defined terms"],"plain_english_summary":"This is an **Airworthiness Directive (AD)** — essentially a mandatory safety fix ordered by Australia's Civil Aviation Safety Authority (CASA) for specific aircraft.\n\n**What it does:**\n- **Restricts cabin pressure differential** on certain Gulfstream (formerly Grumman) G1159 and G-IV series business jets\n- \"Cabin pressure differential\" means the difference in air pressure between the inside of the pressurised cabin and the outside atmosphere — too much pressure difference can stress the airframe\n\n**Who it affects:**\n- Owners and operators of Gulfstream G1159 and G-IV series aircraft with **serial numbers 001 to 229 and 775**\n- This covers early production models of these luxury business jets\n\n**What must be done:**\n- Operators must follow the instructions in **Grumman Customer Bulletin No. 270A** to comply with this directive\n- Alternatively, they can reference the equivalent US Federal Aviation Administration (FAA) directive (AD 78-14-06)\n\n**Why it matters:**\n- This prevents potential structural failure or decompression incidents caused by excessive pressure loads on the airframe\n- The \"12/78\" date suggests this addresses a known safety issue from December 1978\n- Non-compliance means the aircraft cannot legally fly in Australian airspace"},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":true,"description":"This instrument is labelled as Amendment 2 (Amdt 2), which indicates it amends a prior directive. The AD text provided does not specify what was changed from the original version or how the scope was altered; it only restates applicability and delegates to Grumman Customer Bulletin No. 270A (Document; Applicability)."},"complexity_factors":["AD text is short and delegates technical detail to external documents (Grumman Customer Bulletin No.270A and FAA AD 78-14-06), so understanding full obligations requires consulting those documents (Document; Compliance).","Applicability is narrow and defined by serial numbers (001–229 and 775), which reduces population size but requires accurate aircraft identification (Applicability).","Operational and cost impacts are not specified in the AD itself, creating uncertainty until the requirement document is reviewed (Compliance).","Regulatory responsibility (CASA) is clear, but technical discretion is held by the manufacturer/FAA documents the AD references (Document; Compliance)."],"plain_english_summary":"This AD covers Gulfstream G1159/G‑IV aeroplanes (S/N 001–229 and 775) and requires operators to follow Grumman Customer Bulletin No. 270A or FAA AD 78‑14‑06 to impose restrictions on cabin pressure differential.  \n\nAffected operators must carry out the inspections, limits, repairs or modifications set out in those documents, bear the associated costs, and obtain the referenced bulletin/AD to determine exact workscopes and operational effects."}},"importantCases":[],"_links":{"self":"/api/acts/ad-g1159-24-amdt-2-cabin-pressure-differential-restriction","history":"/api/acts/ad-g1159-24-amdt-2-cabin-pressure-differential-restriction/history","analysis":"/api/acts/ad-g1159-24-amdt-2-cabin-pressure-differential-restriction/analysis","conflicts":"/api/acts/ad-g1159-24-amdt-2-cabin-pressure-differential-restriction/conflicts","importantCases":"/api/acts/ad-g1159-24-amdt-2-cabin-pressure-differential-restriction/important-cases","documents":"/api/acts/ad-g1159-24-amdt-2-cabin-pressure-differential-restriction/documents"}}