{"id":"F2006B11135","name":"AD/LEARJET/19 - Aileron Lower Skin - Inspection","slug":"ad-learjet-19-aileron-lower-skin-inspection","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":56818,"registerId":"commonwealth-F2006B11135-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/LEARJET/19 - Aileron Lower Skin - 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 Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n \n\n![](image.001.png)  Gates Learjet 24 & 25 Series Aeroplanes\n\n \n\nAD/LEARJET/19 Aileron Lower Skin - Inspection 2/80\n\nApplicability: All model 23 with S/Nos. 23-003 to 23-099;\n\n \n\nAll model 24 with S/Nos. 24-100 to 24-357;\n\n \n\nAll model 25 with S/Nos. 25-003 to 24-291.\n\n \n\nDocument: Gates Learjet SB No. 23/24/25-295.\n\n \n\nCompliance: Within 100 hours time in service after 31 March 1980.\n\n \n\nBackground: The drain holes in the aileron lower skin may not be correctly installed or serviceable.\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 is a discrete, single-issue Airworthiness Directive from 1980 addressing a specific manufacturing defect. It has not expanded beyond its original narrow scope of inspecting drain holes on specific Learjet models."},"complexity_factors":["Single, discrete maintenance task with clear applicability criteria","Only 4 operational paragraphs (Applicability, Document, Compliance, Background)","No defined terms section or interpretation provisions","No cross-references to other legislation or regulations","Simple conditional logic: if serial number in range → compliance required","Fixed deadline (100 hours after specific date) with no exceptions or extensions mentioned"],"plain_english_summary":"This is an **Airworthiness Directive** (AD) — a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA) that requires specific maintenance action on certain aircraft.\n\n**What it does:**\nOrders owners and operators of specific Gates Learjet aircraft to inspect the drain holes in the aileron (the hinged flap on the wing that controls rolling) lower skin.\n\n**Who it affects:**\n- Owners and operators of specific Learjet models 23, 24, and 25 with particular serial numbers (manufacturing identification numbers)\n- Specifically excludes some early and late production aircraft based on serial number ranges\n\n**Why it matters:**\nDrain holes allow water to escape from the aileron structure. If these holes are blocked, missing, or incorrectly installed, water can accumulate and cause corrosion or structural damage — potentially compromising flight safety and control.\n\n**What must be done:**\n- Inspection must be completed within **100 hours of flight time** after 31 March 1980\n- The technical procedure is found in **Gates Learjet Service Bulletin No. 23/24/25-295**\n\n**Key point:** This is a **time-critical safety mandate**. Non-compliance means the aircraft cannot legally operate in Australian airspace."},"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"The AD as provided sets a targeted inspection requirement for specified Gates Learjet 23, 24 and 25 series aeroplanes and references a single service bulletin for procedures (Applicability; Document; Compliance). The document does not indicate any expansion or narrowing of that set of affected aircraft beyond the stated serial-number ranges, nor does it alter the basic scope of requiring inspection of the aileron lower skin drain holes (Background)."},"complexity_factors":["Single, time-limited action: one inspection requirement with a clear compliance window (Compliance).","Narrow applicability limited to specific models and serial number ranges, which simplifies identification of affected aircraft (Applicability).","Reference to a manufacturer service bulletin for procedures centralises technical guidance but requires users to consult an external document (Document).","AD text does not include explicit corrective-action steps or alternative compliance paths, creating some implementation discretion and potential follow-on work (Document; Background).","Historical compliance deadline and fixed-hour window require scheduling within operators' maintenance programs (Compliance)."],"plain_english_summary":"This AD mandates a one‑time inspection of the aileron lower‑skin drain holes on specified Gates Learjet 23/24/25 aircraft, to be done per Gates Learjet SB No. 23/24/25‑295 within 100 hours TIS after 31 March 1980. It affects owners, operators and maintenance organisations, who bear inspection and any repair costs; the aim is to confirm drain holes are present and serviceable to mitigate related safety risks."}},"importantCases":[],"_links":{"self":"/api/acts/ad-learjet-19-aileron-lower-skin-inspection","history":"/api/acts/ad-learjet-19-aileron-lower-skin-inspection/history","analysis":"/api/acts/ad-learjet-19-aileron-lower-skin-inspection/analysis","conflicts":"/api/acts/ad-learjet-19-aileron-lower-skin-inspection/conflicts","importantCases":"/api/acts/ad-learjet-19-aileron-lower-skin-inspection/important-cases","documents":"/api/acts/ad-learjet-19-aileron-lower-skin-inspection/documents"}}