{"id":"F2006B11123","name":"AD/LEARJET 35/8 - Refrigeration System Condenser Fan - Inspection and Replacement","slug":"ad-learjet-35-8-refrigeration-system-condenser-fan-inspection-and-replacement","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":56797,"registerId":"commonwealth-F2006B11123-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/LEARJET 35/8 - Refrigeration System Condenser Fan - Inspection and Replacement","content":"COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 \\- 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n![](image.001.png)  \nGates Learjet 35 and 36 Series Aeroplanes\n\nAD/LEARJET 35/8 Refrigeration System Condenser\n\nFan \\- Inspection and Replacement\n\n  \n9/78\n\nApplicability: Model 35 with S/Nos. 35-001 to 35-194. Model 36 with S/Nos. 36-001 to 36-040. And any 35/36 Series Learjet which has had a Condenser Fan changed since 1 July 1977.\n\nRequirement: 1. Inspect the P/No. rubber-stamped on a blade of the refrigeration condenser fan.\n\n2. If the fan bears the P/No. 6608059-3, attach a placard worded as follows to the instrument panel adjacent to the refrigeration system control switch:\n\nWARNING\n\nDO NOT OPERATE REFRIGERATION SYSTEM UNDER ANY CIRCUMSTANCES ON THE GROUND OR IN THE AIR UNTIL FAN HAS BEEN REPLACED.\n\nNote: The correct fans have blades which taper in thickness towards the tip and bear the P/Nos. 6608059-2 or 6608059-4.\n\nor Gates Learjet SB 35/36-21-3.\n\nCompliance: Before further flight.","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, targeted safety directive addressing a specific mechanical defect in specific aircraft. It has not expanded beyond its original purpose of mandating inspection and replacement of a faulty condenser fan."},"complexity_factors":["Very short document (approximately 150 words)","Only 3 defined applicability criteria (specific serial number ranges plus one conditional category)","Simple binary compliance requirement (inspect → if condition met, take action)","No cross-references to other legislation or regulations beyond the enabling authority (Civil Aviation Regulations 1998 Part 39)","Single exception/note clarifying correct replacement parts","No nested conditions or exceptions to exceptions"],"plain_english_summary":"This is an **Airworthiness Directive** (a mandatory safety order) issued by Australia's Civil Aviation Safety Authority for specific Gates Learjet 35 and 36 series aircraft.\n\n**What it does:**\n- Requires owners/operators to check the part number stamped on their aircraft's refrigeration system condenser fan blades\n- If the fan is part number 6608059-3, the aircraft owner must:\n  - Attach a warning placard (sign) next to the refrigeration control switch stating the system must not be used until the fan is replaced\n  - Replace the faulty fan with the correct version (part numbers 6608059-2 or 6608059-4, which have blades that taper toward the tip)\n\n**Who it affects:**\n- Owners and operators of:\n  - Learjet Model 35 aircraft with serial numbers 35-001 through 35-194\n  - Learjet Model 36 aircraft with serial numbers 36-001 through 36-040\n  - Any Learjet 35/36 that has had its condenser fan replaced since 1 July 1977\n\n**Why it matters:**\nThe specified fan (P/No. 6608059-3) appears to be defective or unsafe—likely prone to failure that could damage the aircraft or endanger passengers. The directive grounds use of the refrigeration system until the unsafe part is replaced, preventing potential in-flight emergencies or ground incidents.\n\n**Compliance deadline:** Before the aircraft flies again (immediate action required)."},"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"The directive's scope, as written, targets a specific hardware condition on defined serial-number ranges and on aircraft that have had condenser fans changed since 1 July 1977. The prescribed actions (inspect, placard if P/N 6608059-3 is present, replace before flight) implement that targeted scope directly and do not expand or narrow it beyond the stated applicability and remedial steps (Applicability; Requirement; Compliance; Note)."},"complexity_factors":["Narrow, well‑defined applicability by model and serial number (Applicability).","Single, short sequence of actions: inspect blade P/No.; if P/No. 6608059-3 is present, attach specified placard and replace fan (Requirement 1–2).","Immediate compliance required before further flight creates operational urgency but no procedural ambiguity (Compliance).","Identification relies on a visible, rubber-stamped part number and a simple physical characteristic (blade taper) to distinguish acceptable parts (Requirement; Note).","Manufacturer service bulletin referenced for additional detail rather than complex regulatory procedures (Note)."],"plain_english_summary":"This directive requires operators of certain Gates Learjet 35/36 aeroplanes to inspect the refrigeration condenser fan blade for its stamped part number and, if P/N 6608059-3 is fitted, attach a prescribed warning placard and replace the fan before further flight. It affects specified serial-numbered Model 35/36 aircraft and any with a fan changed since 1 July 1977, plus maintenance organisations and parts suppliers.\n\nIt matters because it bars operation of the refrigeration system with the disallowed fan, imposes inspection, replacement and downtime costs on owners, and limits operator discretion; correct part identification and use of the Gates Learjet service bulletin are critical."}},"importantCases":[],"_links":{"self":"/api/acts/ad-learjet-35-8-refrigeration-system-condenser-fan-inspection-and-replacement","history":"/api/acts/ad-learjet-35-8-refrigeration-system-condenser-fan-inspection-and-replacement/history","analysis":"/api/acts/ad-learjet-35-8-refrigeration-system-condenser-fan-inspection-and-replacement/analysis","conflicts":"/api/acts/ad-learjet-35-8-refrigeration-system-condenser-fan-inspection-and-replacement/conflicts","importantCases":"/api/acts/ad-learjet-35-8-refrigeration-system-condenser-fan-inspection-and-replacement/important-cases","documents":"/api/acts/ad-learjet-35-8-refrigeration-system-condenser-fan-inspection-and-replacement/documents"}}