{"id":"F2006B10063","name":"AD/G159/19 Amdt 4 - Landing Gear","slug":"ad-g159-19-amdt-4-landing-gear","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":55508,"registerId":"commonwealth-F2006B10063-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/G159/19 Amdt 4 - Landing Gear","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/G159/19 Amdt 4 Landing Gear 13/89\n\nApplicability: All models.\n\n \n\nRequirement: Carry out a fluorescent dye NDI for cracking of the landing gear aluminium forgings in accordance with Gulfstream Customer Bulletin No. 228B.\n\n \n\nCompliance: Within 150 landings after 28 December 1989, or since last overhaul whichever is the later, thereafter in accordance with the G1 Inspection Schedule.\n\n \n\nBackground: The manufacturer has specified a range of NDI procedures to relieve this inspection, and enable inclusion into the Inspection Schedule. The Authority has called up fluorescent dye as the most suitable for Australia conditions.\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 is a standard, narrow airworthiness directive focused on a specific safety inspection for a specific aircraft type. It has not expanded beyond its original purpose of ensuring landing gear integrity through mandated inspection."},"complexity_factors":["Very short document (approximately 150 words of substantive content)","Only 1 defined term implicitly referenced (NDI — non-destructive inspection)","Single, clear compliance pathway with only one conditional element (the 'whichever is later' timing rule)","No cross-references to other legislation or complex procedural requirements","Straightforward applicability (all models of one aircraft series)","Single technical requirement referencing an external manufacturer bulletin (Gulfstream Customer Bulletin No. 228B)"],"plain_english_summary":"This is an **Airworthiness Directive** — a mandatory safety order issued by Australia's aviation regulator (CASA) that requires owners and operators of specific aircraft to perform a safety inspection.\n\n**What it does:**\n- Requires owners of **Gulfstream G.159 series aeroplanes** (all models) to inspect their landing gear for cracks using a special fluorescent dye test.\n- This test is a type of **non-destructive inspection (NDI)** — a way to check for hidden damage without taking the part apart or breaking it.\n\n**Who it affects:**\n- Anyone who owns, operates, or maintains a Gulfstream G.159 aircraft in Australia.\n\n**When it must be done:**\n- Within 150 landings after 28 December 1989, **or** since the landing gear was last overhauled — whichever happened later.\n- After that first inspection, it becomes part of the regular maintenance schedule (the \"G1 Inspection Schedule\").\n\n**Why it matters:**\n- Cracks in landing gear can lead to catastrophic failure during takeoff or landing. This directive was issued because the manufacturer identified a risk of cracking in the aluminium forgings (the shaped metal parts) of the landing gear. The Australian regulator specified the fluorescent dye method as the most reliable approach for local conditions."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":true,"description":"The instrument narrows the acceptable inspection method from a manufacturer‑specified range of NDI procedures to a single prescribed method (fluorescent‑dye NDI) for Australian operations, and sets a specific initial compliance window (150 landings after 28 December 1989 or since last overhaul) with ongoing inspections under the G1 Inspection Schedule. This is indicated by the Background (manufacturer specified a range; Authority called up fluorescent dye) and by the Requirement and Compliance provisions."},"complexity_factors":["Clear, single technical requirement (fluorescent‑dye NDI) reduces procedural complexity.","Dependence on an external technical document (Gulfstream Customer Bulletin No. 228B) requires operators to obtain and follow that material.","Time‑based compliance tied to landing counts and overhaul dates requires operational tracking.","Integration into the G1 Inspection Schedule requires cross‑reference to another regulatory schedule (additional lookup).","Restriction to one NDI method reduces choice but may create practical implementation complexity (equipment/skills)."],"plain_english_summary":"Operators of all Gulfstream G.159 series aeroplanes must carry out a fluorescent‑dye non‑destructive inspection of the landing‑gear aluminium forgings per Gulfstream Customer Bulletin No.228B within 150 landings after 28 Dec 1989 (or within 150 landings since the last overhaul if later), then continue inspections under the G1 schedule. The AD prescribes the specific NDI method for Australia, limits operators’ choice of technique, and places inspection costs, downtime and any repairs on aircraft owners/operators."}},"importantCases":[],"_links":{"self":"/api/acts/ad-g159-19-amdt-4-landing-gear","history":"/api/acts/ad-g159-19-amdt-4-landing-gear/history","analysis":"/api/acts/ad-g159-19-amdt-4-landing-gear/analysis","conflicts":"/api/acts/ad-g159-19-amdt-4-landing-gear/conflicts","importantCases":"/api/acts/ad-g159-19-amdt-4-landing-gear/important-cases","documents":"/api/acts/ad-g159-19-amdt-4-landing-gear/documents"}}