{"id":"F2006B11156","name":"AD/LEARJET/4 - Tip Tank Fuel Pressure Relief - Modification","slug":"ad-learjet-4-tip-tank-fuel-pressure-relief-modification","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":56849,"registerId":"commonwealth-F2006B11156-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/LEARJET/4 - Tip Tank Fuel Pressure Relief - Modification","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/4 Tip Tank Fuel Pressure Relief - Modification 9/73\n\nApplicability: Model 24 with S/no. 24-218 and 24-230 to 24-269, Model 25 with S/no. 25-061, 25-\n\n064 and 25-070 to 25-124.\n\n \n\nDocument: Modification Kit No. AMK 73-2.\n\n \n\nCompliance: Within 100 hours time in service after 28 September 1973.\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\n \n\n \n","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"The supplied directive sets a specific, limited obligation (install Modification Kit No. AMK 73-2 on named serial-numbered Learjet 24 and 25 aircraft within a stated time). The text contains no indication that the scope of affected aircraft or the required action has been altered from an earlier version; therefore there is no evidence in the supplied document that the scope has changed from any prior intent."},"complexity_factors":["Narrow and specific applicability by model and serial number reduces interpretive complexity (Applicability).","Single, discrete required action (install AMK 73-2) simplifies compliance steps (Document).","Clear, short compliance window (100 hours TIS after a dated trigger) simplifies scheduling but creates logistical pressure (Compliance).","Absence of procedural detail in the directive means operators must obtain installation instructions elsewhere (kit documentation/maintenance provider), adding a minor procedural coordination complexity.","Potential supply or scheduling delays for the kit and qualified maintenance can create practical execution complexity despite the directive's legal simplicity."],"plain_english_summary":"The directive mandates installing Modification Kit No. AMK 73-2 to the tip‑tank fuel system of specific Learjet 24 and 25 airframes (listed by serial number). Compliance is mandatory within 100 hours time-in-service after 28 September 1973. Owners/operators bear kit and installation costs, must schedule downtime, and rely on maintenance providers for fitting and records, concentrating costs and short-term demand on the identified aircraft."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, single-issue airworthiness directive from 1973 addressing a specific mechanical modification. It has not expanded beyond its original purpose of mandating a fuel system safety fix for specific Learjet serial numbers."},"complexity_factors":["Extremely short document (approximately 150 words)","Only 4 defined elements: applicability (specific serial numbers), document reference (AMK 73-2), compliance deadline, and affected aircraft models","No cross-references to other legislation or regulations","No conditional logic or exceptions — straightforward mandatory action","Single compliance pathway with clear deadline","No interpretation section or defined terms"],"plain_english_summary":"**What this is:** This is an **Airworthiness Directive (AD)** — a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA). Think of it as a \"recall notice\" for aircraft, but legally binding.\n\n**What it requires:** Owners and operators of specific **Gates Learjet 24 and 25 series aircraft** must install a **modification kit (AMK 73-2)** to fix a problem with the **tip tank fuel pressure relief system**. The tip tanks are fuel tanks located at the wingtips.\n\n**Who it affects:**\n- **Model 24 aircraft** with serial numbers 24-218 and 24-230 through 24-269\n- **Model 25 aircraft** with serial numbers 25-061, 25-064, and 25-070 through 25-124\n\n**The deadline:** The modification must be completed **within 100 hours of flight time** after 28 September 1973.\n\n**Why it matters:** Fuel pressure relief systems prevent dangerous pressure buildup in fuel tanks. Without this fix, there could be a risk of fuel system failure, fire, or explosion. This directive ensures these specific Learjets meet safety standards."}},"importantCases":[],"_links":{"self":"/api/acts/ad-learjet-4-tip-tank-fuel-pressure-relief-modification","history":"/api/acts/ad-learjet-4-tip-tank-fuel-pressure-relief-modification/history","analysis":"/api/acts/ad-learjet-4-tip-tank-fuel-pressure-relief-modification/analysis","conflicts":"/api/acts/ad-learjet-4-tip-tank-fuel-pressure-relief-modification/conflicts","importantCases":"/api/acts/ad-learjet-4-tip-tank-fuel-pressure-relief-modification/important-cases","documents":"/api/acts/ad-learjet-4-tip-tank-fuel-pressure-relief-modification/documents"}}