{"id":"F2006B11165","name":"AD/LJ45/4 Amdt 1 - Cockpit Foot Warmer","slug":"ad-lj45-4-amdt-1-cockpit-foot-warmer","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":56862,"registerId":"commonwealth-F2006B11165-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/LJ45/4 Amdt 1 - Cockpit Foot Warmer","content":"![](image.001.png)\n\nAIRWORTHINESS DIRECTIVE\n\n![](image.001.png)  \n\nFor the reasons set out in the background section, the CASA delegate whose signature appears below revokes Airworthiness Directive (AD) AD/LJ45/4 and issues the following AD under subregulation 39.1 (1) of CASR 1998. The AD requires that the action set out in the requirement section (being action that the delegate considers necessary to correct the unsafe condition) be taken in relation to the aircraft or aeronautical product mentioned in the applicability section: (a) in the circumstances mentioned in the requirement section; and (b) in accordance with the instructions set out in the requirement section; and (c) at the time mentioned in the compliance section.\n\n![](image.001.png)  \n\nLearjet 45 Series Aeroplanes\n\nAD/LJ45/4\n\nAmdt 1\n\n  \nCockpit Foot Warmer 3/2004\n\nApplicability: Model 45 aeroplanes, serial numbers 45-005 through 45-213 inclusive.\n\nRequirement: 1. Unless already accomplished in accordance with AD/LJ45/4 original issue, pull (open) the FOOT WARM circuit breaker, located on the copilot's circuit breaker panel, and install a collar on the FOOT WARM circuit breaker, per Bombardier Aerospace Learjet Alert Service Bulletin SB A45-21-14, dated 3 May 2002.\n\n2. Reactivate the foot warmer system by removing the collar and closing the FOOT WARM circuit breaker.\n\nNote 1: FAA AD 2002-17-01 Amdt 39-12866 and FAA Small Airplane Directorate Alternate Method of Compliance (AMOC) letter dated 5 November 2003 refer. The FAA AMOC letter is included in Bombardier Aerospace Advisory Wire 21-006.\n\nCompliance: For Requirement 1 \\- As of the effective date of this Amendment.\n\nFor Requirement 2 \\- Following the optional replacement/modification of the pilot and co-pilot heel plate assemblies in accordance with Bombardier Aerospace Learjet Service Bulletin SB 45-21-15.\n\nNote 2: SB 45-21-15 requires either concurrent or prior incorporation of SB45-21-2 on aeroplanes serial numbers 45-001 through 45-119.\n\nThis Amendment becomes effective on 18 March 2004.\n\nBackground: The United States Federal Aviation Administration has received reports of smoke in the cockpit caused by electrical short circuits between the pilot's and copilot's foot warmers and the composite floorboards. A short circuit in a foot warmer causes electrical current to flow through the metal heelplate of the foot warmer to the composite floorboards. Due to the high resistance of the composite floorboards, the circuit breaker may not open, or the opening could be significantly delayed, which could result in outgassing of the faceply material of the composite floorboards, and consequent smoke in the cockpit.\n\nThe original issue of this Directive required pulling the FOOT WARM circuit breaker and installing a collar on that circuit breaker.\n\nLearjet 45 Series Aeroplanes\n\nAD/LJ45/4 Amdt 1 (continued)\n\nThis amendment introduces an optional terminating action to the deactivation of the cockpit foot warmer system.\n\n\\` The original issue of this Airworthiness Directive became effective on 18 September 2002.\n\n![Signature of James Coyne Delegate of the Civil Aviation Safety Authority](image.002.png)  \n\nJames Coyne\n\nDelegate of the Civil Aviation Safety Authority 22 January 2004\n\n![](image.001.png)  \n\nThe above AD is notified in the Commonwealth of Australia Gazette on 25 February 2004.","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":true,"description":"Yes. The amendment preserves the original deactivation requirement (pull circuit breaker and install collar) but adds an optional terminating action: operators may reactivate the foot-warmers after completing the Bombardier SB 45-21-15 modification. It also notes that SB45-21-15 requires concurrent or prior incorporation of SB45-21-2 for serials 45-001 through 45-119, creating additional preconditions for some aircraft."},"complexity_factors":["Clear, limited applicability: specific model and serial-number range (45-005 through 45-213).","Requires physical maintenance action (pull circuit breaker, install collar) with simple immediate compliance for Requirement 1.","Conditional/optional terminating action: reactivation only after incorporation of Bombardier SB 45-21-15, adding sequencing complexity for operators.","Cross-references to other service bulletins and FAA documents (FAA AD, FAA AMOC, SB45-21-2) increase administrative tracking.","Compliance timing split (immediate deactivation vs. later reactivation) introduces operational planning and record-keeping burdens."],"plain_english_summary":"This amendment to AD/LJ45/4 requires operators of Learjet 45 aeroplanes (serials 45-005 to 45-213) to disable the cockpit foot-warmers by pulling the FOOT WARM circuit breaker and fitting a collar, and allows reactivation only after an optional hardware modification per Bombardier SB 45-21-15. CASA's delegate mandates compliance; aircraft operators and maintenance organisations must carry out and pay for the work and record compliance. The measure addresses electrical shorting between foot warmers and composite floorboards that can cause cockpit smoke."},"flash_summary_failed":{"failed":true,"reason":"A positive credit balance is required for all requests, including BYOK, so fallback providers remain available. Add credits at https://vercel.com/d?to=%2F%5Bteam%5D%2F%7E%2Fai%3Fmodal%3Dtop-up to continue.","source":"analysis-cron"},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This amendment remains tightly scoped to its original purpose — addressing the electrical short circuit hazard in Learjet 45 cockpit foot warmers. The amendment adds an optional terminating action (reactivation after modification) but does not expand beyond the original safety issue or aircraft population."},"complexity_factors":["Single, specific aircraft model and narrow serial number range (45-005 through 45-213)","Only two operational requirements with clear conditional logic","Minimal cross-referencing (only to specific manufacturer service bulletins and one prior FAA directive)","Short document (approximately 400 words)","No nested definitions or interpretation sections","Simple two-stage compliance structure (immediate deactivation, optional reactivation)"],"plain_english_summary":"This AD requires operators of certain Learjet 45 serials to immediately pull the cockpit foot-warmers circuit breaker and install a locking collar to keep it off, because electrical shorts can heat composite floorboards, impede breaker trip, and cause outgassing/smoke or fire. Reactivation of the warmers is allowed only after installing specified replacement heel-plate parts per the manufacturer’s service instructions."}},"importantCases":[],"_links":{"self":"/api/acts/ad-lj45-4-amdt-1-cockpit-foot-warmer","history":"/api/acts/ad-lj45-4-amdt-1-cockpit-foot-warmer/history","analysis":"/api/acts/ad-lj45-4-amdt-1-cockpit-foot-warmer/analysis","conflicts":"/api/acts/ad-lj45-4-amdt-1-cockpit-foot-warmer/conflicts","importantCases":"/api/acts/ad-lj45-4-amdt-1-cockpit-foot-warmer/important-cases","documents":"/api/acts/ad-lj45-4-amdt-1-cockpit-foot-warmer/documents"}}