{"id":"F2006B11097","name":"AD/LEARJET 35/19 Amdt 1 - Stall Warning Accelerometer","slug":"ad-learjet-35-19-amdt-1-stall-warning-accelerometer","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":56757,"registerId":"commonwealth-F2006B11097-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/LEARJET 35/19 Amdt 1 - Stall Warning Accelerometer","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 35/19\n\nAmdt 1\n\n  \nStall Warning Accelerometer 2/86\n\nApplicability: All models 35, 35A, 36, 36A with S/Nos. 35-001 to 35-505, 36-001 to 36-053 NOT incorporating Gates Learjet Aircraft Accessory Kit 83-2.\n\nRequirement: Gates Learjet SB 35/36-27-12B;\n\nNote: FAA AD 82-01-05 R2 also refers.\n\nCompliance: Unless Already Accomplished \\- Within the next 50 hours time in service after 9 March 1982 and thereafter at every 220 hours time in service.\n\nBackground: Faulty accelerometers or an improperly wired stall warning system when coupled with an inadvertent stick pusher operation during cruise flight could present control forces and flight upset beyond the capability of the crew to recover. Amdt 1 identifies applicable aeroplane serial numbers and escalates check hours.","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This amendment remains tightly scoped to its original safety purpose. Amendment 1 makes two technical adjustments: (1) specifying exact aircraft serial numbers previously covered by broader language, and (2) escalating (increasing) the inspection interval from the original directive. These are refinements within the original safety intent, not scope expansion."},"complexity_factors":["Single, specific technical requirement referencing an external manufacturer service bulletin","Limited applicability scope (4 specific models, defined serial number ranges, one exclusion)","Simple compliance structure: one-time initial check + recurring interval","No nested definitions, conditional logic, or cross-references to other legislation beyond a single FAA AD citation","Background explanation provided in plain language","Total length: approximately 150 words"],"plain_english_summary":"This is an **Airworthiness Directive** (a mandatory safety order) issued by Australia's Civil Aviation Safety Authority for specific Learjet aircraft models.\n\n**What it does:**\nRequires owners and operators of certain Gates Learjet 35 and 36 series aircraft to inspect and maintain the **stall warning accelerometer** — a sensor that detects when the plane is approaching a stall (losing lift) and triggers warnings or automatic safety systems.\n\n**Who it affects:**\n- Aircraft models: Learjet 35, 35A, 36, and 36A\n- Serial numbers: 35-001 through 35-505, and 36-001 through 36-053\n- **Excludes** aircraft that have been modified with \"Gates Learjet Aircraft Accessory Kit 83-2\"\n\n**What must be done:**\n- Follow the technical instructions in **Gates Learjet Service Bulletin 35/36-27-12B** (the manufacturer's official repair notice)\n- Complete the first check within **50 flight hours** after 9 March 1982\n- Repeat the check **every 220 flight hours** thereafter\n\n**Why it matters:**\nFaulty accelerometers or wiring problems in the stall warning system could cause the **stick pusher** (an automatic device that pushes the control column forward to prevent a stall) to activate unexpectedly during normal cruise flight. This \"Amendment 1\" updates the original 1982 directive by clarifying which specific aircraft serial numbers are affected and increasing the inspection interval from the original requirement.\n\n**Key safety risk:** If the stick pusher fires at the wrong time, the sudden control forces could be so severe that the flight crew cannot recover, potentially causing loss of control."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":true,"description":"Amdt 1 alters scope from the prior instrument by explicitly identifying the serial-number ranges of affected aeroplanes (35-001 to 35-505 and 36-001 to 36-053) and by changing the inspection/check-hour requirements (the amendment \"identifies applicable aeroplane serial numbers and escalates check hours\"). Concretely, the AD now applies only to aircraft without Gates Learjet Aircraft Accessory Kit 83-2 and imposes an initial check within 50 hours after 9 March 1982 followed by recurring checks at 220-hour intervals (Applicability; Compliance; Amdt 1 summary)."},"complexity_factors":["Narrow applicability tied to specific serial-number ranges and an explicit exclusion for aircraft with Kit 83-2 (Applicability)","Cross-reference to an external manufacturer document (Gates Learjet SB 35/36-27-12B) for the technical steps (Requirement)","A two-stage timing regime: an initial short-term mandatory check (within 50 hours after a fixed date) and recurring checks at fixed flight-hour intervals (every 220 hours) (Compliance)","Reference to a related FAA AD that operators may need to consider for harmonisation (Note)","Amendment updates scope and timing (Amdt 1), requiring comparison with earlier AD versions to understand differences"],"plain_english_summary":"What this directive does, mechanically:\n\n- It applies to Gates Learjet 35, 35A, 36 and 36A aeroplanes with serial numbers 35-001 to 35-505 and 36-001 to 36-053, except those that already have Gates Learjet Aircraft Accessory Kit 83-2 installed (Applicability).\n- It requires operators to carry out the maintenance/inspection actions set out in Gates Learjet Service Bulletin SB 35/36-27-12B (Requirement).\n- It sets timing for those actions: if not already done, the first check must be done within the next 50 hours time in service after 9 March 1982, and thereafter the checks must be repeated at every 220 hours time in service (Compliance).\n\nWhy the directive was issued (official rationale):\n\n- The AD states that faulty stall warning accelerometers or an improperly wired stall warning system, when combined with an inadvertent stick pusher activation during cruise, could produce control forces and a flight upset beyond what the crew could recover from (Background). The AD therefore implements the service bulletin inspection/rectification requirement to address that risk.\n\nWho is affected and who pays:\n\n- Aircraft owners/operators of the specified serial-number Learjet 35/36 series without kit 83-2 are required to comply. They bear the direct costs: doing the initial and recurring checks, any labour and parts required by the service bulletin, and any aircraft downtime caused by the work (Applicability; Requirement; Compliance).\n\nIncentives, trade-offs and behaviour the rule changes:\n\n- The directive imposes an ongoing maintenance obligation (rechecks every 220 hours), which increases operators' recurrent maintenance workload and scheduling needs (Compliance).\n- Aircraft that already have Accessory Kit 83-2 are outside the AD’s applicability; that difference in applicability creates a practical substitute: operators may face a choice between recurring inspections or installing the kit if that is an available, permitted option (Applicability).\n- The AD refers operators to a manufacturer service bulletin (Requirement). That makes the service bulletin the operative technical procedure; operators must follow the SB to meet the AD. This concentrates technical decision-making about exactly what to do in the SB (Requirement).\n\nCompliance burden and implementation risks:\n\n- The directive specifies short-term compliance timing (an initial check within 50 hours after a fixed date) followed by recurring intervals (every 220 hours). That creates immediate scheduling pressure for operators who have affected aircraft (Compliance).\n- The AD does not in itself describe enforcement measures or penalties in this text; it specifies the required actions and intervals and points to the manufacturer SB for the technical steps (Requirement; Compliance).\n\nOther technical and administrative notes:\n\n- The AD cross-references an FAA airworthiness directive (FAA AD 82-01-05 R2) and points operators to Gates Learjet SB 35/36-27-12B for detailed procedures (Note; Requirement).\n- The amendment (Amdt 1) is described as identifying the applicable aeroplane serial numbers and \"escalates check hours\", i.e. it changes which serial numbers are covered and adjusts the inspection/check hour requirements (Amdt 1 summary).\n\nSource citations: statements above are taken from the sections labelled Applicability, Requirement, Compliance, Background and the Amdt 1 summary within the AD text provided."}},"importantCases":[],"_links":{"self":"/api/acts/ad-learjet-35-19-amdt-1-stall-warning-accelerometer","history":"/api/acts/ad-learjet-35-19-amdt-1-stall-warning-accelerometer/history","analysis":"/api/acts/ad-learjet-35-19-amdt-1-stall-warning-accelerometer/analysis","conflicts":"/api/acts/ad-learjet-35-19-amdt-1-stall-warning-accelerometer/conflicts","importantCases":"/api/acts/ad-learjet-35-19-amdt-1-stall-warning-accelerometer/important-cases","documents":"/api/acts/ad-learjet-35-19-amdt-1-stall-warning-accelerometer/documents"}}