{"id":"F2006B11112","name":"AD/LEARJET 35/33 - Outflow/Safety Valve","slug":"ad-learjet-35-33-outflow-safety-valve","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":56776,"registerId":"commonwealth-F2006B11112-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/LEARJET 35/33 - Outflow/Safety Valve","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 35/33 Outflow/Safety Valve 3/96\n\nApplicability: Learjet 35/36 series aircraft as identified in Learjet Service Bulletin SB 35/36-21-19.\n\nRequirement: 1. Unless previously carried out, revise the Aircraft Flight Manual to amend the aircraft maximum operating altitude to 41,000 feet by;\n\n    (a) inserting a CASA 'green page' amendment issued under approval number \"A/35-A36/6\" or,\n\n    (b) inserting Learjet Temporary Flight Manual Change 94-15 dated 9 January 1995.\n\n    2. Unless previously carried out action in accordance with paragraph 2B and 2C of Learjet Service Bulletin 35/36-21-19 dated 3 January 1995.\n\n    3. Remove the aircraft flight manual change introduced in Requirement 1 by application through the CASA District Airworthiness Office responsible for the aircraft.\n\nNote: FAA AD 95-20-03 Amdt 39-9381 refers and supersedes FAA AD 94-26-01 Amdt 39-9097.\n\nCompliance: Requirement 1: Prior to 1 April 1996.\n\nRequirement 2: Prior to 28 February 1997. Requirement 3: On compliance with Requirement 2.\n\nBackground: The manufacturer has advised that valves identified in AlliedSignal Service Bulletin 130406-21-A4011 Revision 3 or 102850-21-4021 Revision 2 may experience fracture or cracking of the poppet valve which could cause rapid decompression of the aircraft. Until affected valves can be replaced a flight manual amendment has been inserted in the Australian flight manual.","sortOrder":0}],"analysis":{"flash_summary_failed":{"failed":true,"reason":"Unauthenticated. Configure AI_GATEWAY_API_KEY or use a provider module. Learn more: https://ai-sdk.dev/unauthenticated-ai-gateway","source":"analysis-cron"},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The AD's measures align with its stated safety purpose: a temporary flight‑manual altitude restriction until affected outflow/safety valves are inspected or replaced per Learjet Service Bulletin (see Requirement 1 and Requirement 2). Removal of the temporary amendment follows completion of the valve actions via CASA District Airworthiness Office (Requirement 3). No material widening or narrowing of scope from the AD's expressed intent is evident in the text."},"complexity_factors":["Cross‑references to multiple service bulletins (Learjet SB 35/36‑21‑19 and AlliedSignal SB numbers) increase technical tracing.","Staged compliance deadlines for different requirements (Requirement 1 by 1 April 1996; Requirement 2 by 28 Feb 1997) add scheduling burden.","Administrative step to remove the flight manual change requires application through the CASA District Airworthiness Office (Requirement 3).","Two alternative means to amend the flight manual (CASA 'green page' or Learjet Temporary Flight Manual Change) create minor choice/configuration decisions for operators.","Applicability limited to aircraft identified in the cited service bulletin requires operators to verify aircraft identity against SB lists."],"plain_english_summary":"This Airworthiness Directive requires operators of Learjet 35/36 aircraft identified in Learjet Service Bulletin 35/36‑21‑19 to amend the Aircraft Flight Manual to limit maximum operating altitude to 41,000 ft and to carry out specified service‑bulletin actions to inspect/replace outflow/safety valves. It targets affected operators because certain valve poppets may crack and cause rapid decompression; the manual amendment is temporary and must be removed after the required valve work is completed."},"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This Airworthiness Directive maintains its original narrow scope — addressing a specific mechanical defect in specific aircraft models. It has not expanded beyond its safety-critical purpose of mandating repairs to faulty outflow valves."},"complexity_factors":["Single specific aircraft type (Learjet 35/36 series) with clear applicability","Only 3 numbered requirements with straightforward sequential compliance","References to external documents (Service Bulletins, FAA ADs) but these are standard aviation practice","Simple conditional logic ('Unless previously carried out')","No nested definitions or interpretation sections","Clear compliance dates and background explanation","Total length is approximately 250 words"],"plain_english_summary":"This CASA Airworthiness Directive orders operators of Learjet 35/36 aircraft to address cracking in Gates outflow/safety valves that can cause rapid decompression. It requires an immediate AFM amendment lowering the max operating altitude to 41,000 ft and, by a later compliance date, valve inspection or replacement per the manufacturer; the altitude restriction may be removed once corrective work is done.  \n\nIt affects owners, operators, maintenance organisations and pilots and aims to prevent hypoxia and catastrophic loss of control at high altitude."}},"importantCases":[],"_links":{"self":"/api/acts/ad-learjet-35-33-outflow-safety-valve","history":"/api/acts/ad-learjet-35-33-outflow-safety-valve/history","analysis":"/api/acts/ad-learjet-35-33-outflow-safety-valve/analysis","conflicts":"/api/acts/ad-learjet-35-33-outflow-safety-valve/conflicts","importantCases":"/api/acts/ad-learjet-35-33-outflow-safety-valve/important-cases","documents":"/api/acts/ad-learjet-35-33-outflow-safety-valve/documents"}}