{"id":"F2006B10074","name":"AD/G159/30 Amdt 1 - Engine Nacelle Firewall - Inspection","slug":"ad-g159-30-amdt-1-engine-nacelle-firewall-inspection","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":55519,"registerId":"commonwealth-F2006B10074-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/G159/30 Amdt 1 - Engine Nacelle Firewall - Inspection","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/G159/30 Amdt 1 Engine Nacelle Firewall - Inspection 10/82\n\nApplicability: All models.\n\n \n\nDocument: Grumman Customer Bulletin No. 293, Amendment 1.\n\n \n\nCompliance: At intervals not exceeding 150 hours time in service after 31 October 1982.\n\n \n\nBackground: Operators have found additional cracks in the centre of the firewall between the two locations described in the original Customer Bulletin.\n\n \n","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a narrow, targeted safety directive addressing a specific airworthiness concern on a specific aircraft type. It has not expanded beyond its original purpose of ensuring firewall integrity through periodic inspection."},"complexity_factors":["Very short document (approximately 150 words)","Only 4 operative provisions: applicability, reference document, compliance deadline, and brief background","No defined terms section","No cross-references to other legislation or regulations","Single, unambiguous compliance requirement (150-hour interval)","No conditional logic, exceptions, or nested provisions"],"plain_english_summary":"This is an **Airworthiness Directive** — a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA). It requires owners and operators of **Gulfstream G.159 series aeroplanes** to inspect the **engine nacelle firewall** (the protective barrier between the engine compartment and the rest of the aircraft) for cracks.\n\n**What it does:**\n- Mandates repeated inspections of a specific structural component that has been found to develop dangerous cracks\n- Requires compliance every **150 hours of flight time** after 31 October 1982\n- References a manufacturer bulletin (Grumman Customer Bulletin No. 293, Amendment 1) for the detailed inspection procedure\n\n**Who it affects:**\n- All operators of Gulfstream (formerly Grumman) G.159 series aircraft\n- Maintenance organisations servicing these aircraft\n\n**Why it matters:**\nFirewalls are critical safety barriers. Cracks in this structure could allow fire or hazardous fumes to penetrate the aircraft cabin or other vital areas. The directive was issued after operators discovered cracks in locations not covered by the original manufacturer bulletin, indicating a broader safety issue than initially identified."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":true,"description":"The amendment expands the inspection emphasis to include additional cracks found in the centre of the firewall that were not covered by the original Customer Bulletin. It also prescribes a recurring inspection interval of not more than 150 hours time in service after 31 October 1982. (Background; Compliance; Document)"},"complexity_factors":["Narrow technical focus (single inspection requirement for a specified component).","Clear, fixed compliance interval (150 hours TIS) reduces interpretive complexity. (Compliance)","Reference to an external technical document (Grumman Customer Bulletin No. 293, Amendment 1) creates dependency on that document for procedural detail. (Document)","Applies to all models but contains limited procedural detail in the directive itself, requiring operators to consult the manufacturer bulletin. (Applicability; Document)","Historical compliance start date (after 31 October 1982) may require operators to reconcile records for older fleets. (Compliance)","Limited scope reduces cross-regulatory interactions, but practical inspection quality and detection uncertainty add operational complexity. (Background; Document)"],"plain_english_summary":"This airworthiness directive requires owners/operators of all Gulfstream (Grumman) G.159 aeroplanes to inspect the engine nacelle firewall per Grumman Customer Bulletin No. 293, Amendment 1, at intervals not exceeding 150 hours TIS (from 31 Oct 1982), after additional cracks were found.  \n\nIt matters because it mandates recurring inspections and any follow‑on repairs, imposing recurring maintenance costs and downtime on operators to mitigate a structural safety risk."}},"importantCases":[],"_links":{"self":"/api/acts/ad-g159-30-amdt-1-engine-nacelle-firewall-inspection","history":"/api/acts/ad-g159-30-amdt-1-engine-nacelle-firewall-inspection/history","analysis":"/api/acts/ad-g159-30-amdt-1-engine-nacelle-firewall-inspection/analysis","conflicts":"/api/acts/ad-g159-30-amdt-1-engine-nacelle-firewall-inspection/conflicts","importantCases":"/api/acts/ad-g159-30-amdt-1-engine-nacelle-firewall-inspection/important-cases","documents":"/api/acts/ad-g159-30-amdt-1-engine-nacelle-firewall-inspection/documents"}}