{"id":"F2006B11160","name":"AD/LEARJET/8 - Main Landing Gear Upper Strut - Inspection","slug":"ad-learjet-8-main-landing-gear-upper-strut-inspection","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":56855,"registerId":"commonwealth-F2006B11160-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/LEARJET/8 - Main Landing Gear Upper Strut - 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/8 Main Landing Gear Upper Strut - Inspection 3/75 Applicability:              Model 24 with S/Nos. 24-100 to 24-297; and model 25 with S/Nos. 25-003 to 25-182. Requirement:               To detect cracks or flaws in the MLG upper strut:-\n\n1. Remove strut from aeroplane, dismantle, clean and inspect using a Fluorescent Dye Penetrant Technique.\n\n\n \n\n2.    If cracks or flaws are disclosed by the inspection in para. 1 evaluate the position of cracks or flaws as per Fig. 1 of Gates Learjet SB No. 23/24/25-259; reject or rework affected upper struts as specified.\n\n \n\nCompliance: Within 600 hours time in service after 30 April 1975 or 30 September 1976 whichever occurs first.\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, targeted safety directive focused on a specific mechanical defect in specific aircraft. It has not expanded beyond its original purpose of ensuring the airworthiness of Learjet main landing gear struts."},"complexity_factors":["Very short document (approximately 200 words)","Only 2 defined applicability criteria (specific serial number ranges)","Simple two-step requirement structure with clear conditional (if cracks found, then follow manufacturer's bulletin)","Single compliance deadline with straightforward calculation method","No cross-references to other legislation or complex defined terms","Relies on external manufacturer service bulletin for technical details rather than embedding complex technical specifications"],"plain_english_summary":"**What this is:** This is an Airworthiness Directive (AD) — essentially a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA). Think of it like a compulsory recall notice, but for aircraft parts rather than cars.\n\n**What it requires:** Owners and operators of specific Gates Learjet 24 and 25 series aircraft must inspect the main landing gear upper strut (the upper part of the leg that holds the wheels) for cracks or flaws. The inspection involves:\n- Removing the strut from the plane\n- Taking it apart and cleaning it\n- Using a fluorescent dye penetrant technique (a special chemical test that makes tiny cracks visible under UV light)\n- If cracks are found, following specific repair or replacement instructions from the manufacturer\n\n**Who it affects:** Specifically, Learjet Model 24 aircraft with serial numbers 24-100 to 24-297, and Model 25 aircraft with serial numbers 25-003 to 25-182.\n\n**Why it matters:** Landing gear failures can be catastrophic. This directive was issued because cracks in the upper strut could lead to landing gear collapse. The compliance deadline (600 flight hours after April 1975 or September 1976) reflects the urgency of catching potential failures before they occur.\n\n**The bottom line:** If you own one of these specific Learjets, you must complete this inspection within the specified flight hours or the aircraft cannot legally fly."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The directive applies to the expressly listed Gates Learjet 24 and 25 serial numbers and prescribes a one-off inspection and disposition process. The text contains no indication that it broadens or narrows scope beyond those specified aircraft or that it imposes continuing inspection obligations; it confines actions to detection and corrective measures per the referenced service bulletin."},"complexity_factors":["Narrow applicability by specific models and serial-number ranges requires operator tracking of affected airframes.","Mandated removal, dismantling and cleaning of the strut increases labor, downtime and access complexity.","Specifies a particular non-destructive test method (Fluorescent Dye Penetrant Technique) requiring trained personnel and materials.","Corrective action depends on evaluation per Figure 1 of Gates Learjet SB No. 23/24/25-259, creating dependency on an external service bulletin and its interpretative judgment.","Outcome options (reject or rework) require access to approved repair capability or replacement parts, which affects cost and scheduling.","Compliance timing uses a 600-hour window tied to one of two calendar dates (whichever is earlier), which can complicate maintenance planning."],"plain_english_summary":"This airworthiness directive requires removal, dismantling, cleaning and fluorescent dye-penetrant inspection of the main landing-gear upper strut on specified Gates Learjet 24 and 25 serial numbers to detect cracks or flaws. If defects are found, operators must evaluate the crack location per Figure 1 of Gates Learjet Service Bulletin No. 23/24/25‑259 and reject or rework the strut as specified. Owners/operators of the listed aircraft pay for inspection and any repairs and must complete the work within 600 hours time in service after 30 April 1975 or 30 September 1976 (whichever is earlier)."}},"importantCases":[],"_links":{"self":"/api/acts/ad-learjet-8-main-landing-gear-upper-strut-inspection","history":"/api/acts/ad-learjet-8-main-landing-gear-upper-strut-inspection/history","analysis":"/api/acts/ad-learjet-8-main-landing-gear-upper-strut-inspection/analysis","conflicts":"/api/acts/ad-learjet-8-main-landing-gear-upper-strut-inspection/conflicts","importantCases":"/api/acts/ad-learjet-8-main-landing-gear-upper-strut-inspection/important-cases","documents":"/api/acts/ad-learjet-8-main-landing-gear-upper-strut-inspection/documents"}}