AIRWORTHINESS DIRECTIVE For 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. Learjet 45 Series Aeroplanes AD/LJ45/2 Brake Control Unit Replacement 4/2002 Applicability: All model Learjet 45 series aeroplanes not fitted with Crane Hydro-Aire Brake Control Units Part Number 42-933-03. Requirement: 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. 2. Remove Learjet Temporary Flight Manual (TFM) changes 2000-01 to 2000-08. Note: Bombardier SB 45-32-9 refers. Compliance: For requirement 1: Within 10 days from the effective date of this Airworthiness Directive. For requirement 2: When the aircraft is fitted with Crane Hydro-Aire Brake Control Unit Part Number 42-933-03. This Airworthiness Directive becomes effective on 18 April 2002. Background: 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. On return to the ramp it was found that one or more brake unit pistons had failed, causing a small brake oil fire. This 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. Learjet 45 Series Aeroplanes AD/LJ45/2 (continued) The Temporary Flight Manual revisions, that are only applicable when pre- modification Brake Control Units are fitted to an aircraft, may be removed from the Flight Manual when post-modification Brake Control Unit P/No. 42-933-03 is fitted. Eugene Paul Holzapfel Delegate of the Civil Aviation Safety Authority 10 March 2002 The above AD is notified in the Commonwealth of Australia Gazette on 27 March 2002.