AIRWORTHINESS DIRECTIVE For the reasons set out in the background section, the CASA delegate whose signature appears below revokes Airworthiness Directive (AD) AD/LJ45/1 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. Learjet 45 Series Aeroplanes AD/LJ45/1 Amdt 1 Nose Wheel Squat Switch Assembly Lubrication 11/2003 Applicability: Model 45 series aeroplanes, serial numbers (S/N) 45-005 through 45-071 inclusive modified per Bombardier Service Bulletin (SB) 45-32-3 and S/N 45-072 through 45- 114 inclusive. Requirement: 1. Apply grease to the rotating disk assembly of the squat switch mechanism of the nose wheel in accordance with Bombardier Aerospace Service Information Letter SIL 32-016 dated 30 March 2000. 2. Replace the camrod of the nose wheel landing gear squat switch in accordance with Bombardier SB 45-32-8 Revision 2 dated 14 March 2001. Replacement of the camrod in accordance with either the original issue or Revision 1 of SB 45- 32-8 accomplished prior to the effective date of this Directive is considered acceptable as compliance with this Requirement. Note: FAA AD 2003-17-08 Amdt 39-13283 refers Compliance: For Requirement 1 - If initially accomplished in accordance with the original issue of this Directive, repeat the lubrication at intervals not to exceed 30 days until Requirement 2 is accomplished. If not accomplished in accordance with the original issue of this Directive, within 30 days from the effective date of this amendment and thereafter at intervals not to exceed 30 days until Requirement 2 is accomplished. For Requirement 2 - Within 300 hours time in service or 12 months after the effective date of this Amendment, whichever occurs first. This Amendment becomes effective on 30 October 2003. Background: The original issue of this Directive required repetitive application of grease to the rotating disk assembly of the nose landing gear squat switch mechanism to prevent moisture contamination and subsequent formation of ice. Learjet 45 Series Aeroplanes AD/LJ45/1 Amdt 1 (continued) Formation of ice could result in bending or damaging of the nose landing gear squat switch assembly, which could drive the nose wheel to an uncommanded angle against the force of the steering system. This condition, if not corrected, could result in the aeroplane departing from the runway at high speeds during landing. This Amendment introduces a terminating action for the Requirement 1 repetitive inspections. The original issue of this Airworthiness Directive became effective on 1 November 2001. Jim Coyne Delegate of the Civil Aviation Safety Authority 18 September 2003 The above AD is notified in the Commonwealth of Australia Gazette on 8 October 2003.