{"id":"F2006B11163","name":"AD/LJ45/2 - Brake Control Unit Replacement","slug":"ad-lj45-2-brake-control-unit-replacement","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":56860,"registerId":"commonwealth-F2006B11163-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"AIRWORTHINESS DIRECTIVE","sectionType":"part","heading":"AIRWORTHINESS DIRECTIVE","content":"# ![](image.001.png)  \nAIRWORTHINESS DIRECTIVE\n\nFor the reasons set out in the background section, the CASA delegate whose signature appears below issues the following Airworthiness Directive (AD) under subregulation 39.1 (1) of CAR 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","sortOrder":0},{"sectionNumber":"AD/LJ45/2 Brake Control Unit Replacement","sectionType":"part","heading":"AD/LJ45/2 Brake Control Unit Replacement 4/2002","content":"# AD/LJ45/2 Brake Control Unit Replacement 4/2002\n\nApplicability: All model Learjet 45 series aeroplanes not fitted with Crane Hydro-Aire Brake Control Units Part Number 42-933-03.\n\nRequirement: 1. Insert Learjet Temporary Flight Manual (TFM) changes 2000-01 to 2000-08 into the Limitations and Normal Procedures Sections of the Flight Manual in accordance with FAA Airworthiness Directive (AD) 2000-08-13.\n\n2. Remove Learjet Temporary Flight Manual (TFM) changes 2000-01 to 2000-08.\n\nNote: Bombardier SB 45-32-9 refers.\n\nCompliance: For requirement 1: Within 10 days from the effective date of this Airworthiness Directive.\n\nFor requirement 2: When the aircraft is fitted with Crane Hydro-Aire Brake Control Unit Part Number 42-933-03.\n\nThis Airworthiness Directive becomes effective on 18 April 2002.\n\nBackground: A report was received by the FAA of an aircraft experiencing a dragging brake (uncommanded brake application condition) after the pilot released the parking brake. The pilot carried out a rejected take-off after the aircraft failed to accelerate properly.\n\nOn return to the ramp it was found that one or more brake unit pistons had failed, causing a small brake oil fire.\n\nThis Airworthiness Directive has therefore been raised to reduce the possibility of a wheel/brake fire and/or a high speed rejected take-off of aircraft fitted with pre- modification Brake Control Units P/No. 42-933-01or -02.","sortOrder":1}],"analysis":{"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"},"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"No change in scope from the directive's stated intent: it targets aircraft fitted with pre‑modification Brake Control Units (P/N 42‑933‑01 or ‑02) by mandating temporary flight manual mitigations until Crane Hydro‑Aire Brake Control Unit P/N 42‑933‑03 is installed, matching the background safety concern described."},"complexity_factors":["Narrow applicability: only Learjet 45s not fitted with Crane Hydro‑Aire P/N 42‑933‑03","Two-step requirement: immediate TFM insert (administrative) and later removal upon hardware replacement (operational)","Short compliance deadline for TFM insert (10 days)","Dependency on external documents (FAA AD 2000‑08‑13 and Bombardier SB 45‑32‑9) for procedural detail","Operational dependence on availability and procurement of specified brake control unit part","Low technical complexity of mandated actions (manual insertion and unit replacement) but requires maintenance coordination"],"plain_english_summary":"This Airworthiness Directive requires operators of Learjet 45 aeroplanes (except those already fitted with Crane Hydro‑Aire Brake Control Unit P/N 42-933-03) to insert specified Temporary Flight Manual changes within 10 days and to remove them once the approved brake control unit is installed. The stated purpose is to reduce the risk of uncommanded brake application, wheel/brake fire or a high‑speed rejected take‑off after reported piston failures. Operators pay for manual updates and any required brake unit replacement; compliance depends on parts availability and maintenance scheduling."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This AD maintains its original narrow scope — addressing a specific brake control unit defect in Learjet 45 aircraft. The document has not expanded beyond its initial safety purpose."},"complexity_factors":["Very short document (approximately 250 words)","Only 2 substantive requirements with clear sequencing","Minimal defined terms (only standard aviation acronyms like TFM, SB, P/No)","No nested exceptions or conditional logic beyond simple 'if/then' applicability","Single cross-reference to an FAA directive and a manufacturer service bulletin","Clear compliance dates and conditions"],"plain_english_summary":"CASA has issued a mandatory Airworthiness Directive for Learjet 45 aircraft lacking the Crane Hydro-Aire brake control unit P/N 42-933-03. Operators must insert temporary Flight Manual changes within 10 days, to be removed after installation of the upgraded unit.\n\nThe AD responds to incidents of “dragging brakes” that caused a failed takeoff and wheel-fire; it aims to prevent wheel fires, aborted high‑speed takeoffs, runway overruns and loss of control."}},"importantCases":[],"_links":{"self":"/api/acts/ad-lj45-2-brake-control-unit-replacement","history":"/api/acts/ad-lj45-2-brake-control-unit-replacement/history","analysis":"/api/acts/ad-lj45-2-brake-control-unit-replacement/analysis","conflicts":"/api/acts/ad-lj45-2-brake-control-unit-replacement/conflicts","importantCases":"/api/acts/ad-lj45-2-brake-control-unit-replacement/important-cases","documents":"/api/acts/ad-lj45-2-brake-control-unit-replacement/documents"}}