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.
Overview
The Airworthiness Directive (AD) AD/LJ45/1 Amendment 1, enacted by the Civil Aviation Safety Authority (CASA) in 2003, addresses safety concerns related to the lubrication and replacement of components in the nose wheel squat switch assembly of Learjet 45 series aeroplanes. This amendment was introduced to correct an unsafe condition where ice formation on the squat switch mechanism could lead to damage and potentially cause the aircraft to veer off the runway during landing. The directive specifies actions to be taken to prevent moisture contamination and subsequent ice formation by applying grease and replacing the camrod of the nose wheel landing gear squat switch. The policy objective is to ensure the continued airworthiness and safety of these aircraft by mitigating risks associated with the identified mechanical issues. This amendment was published in the Commonwealth of Australia Gazette on 8 October 2003 and became effective on 30 October 2003.
Scope and Application
The Airworthiness Directive (AD) applies specifically to the Learjet 45 series aeroplanes with serial numbers ranging from 45-005 through 45-114, inclusive. The directive is aimed at ensuring the safe operation of these aircraft by addressing issues identified with the nose wheel squat switch assembly. It mandates that certain actions be taken in relation to the lubrication and replacement of specific components of the nose wheel landing gear squat switch to prevent unsafe conditions such as the formation of ice, which could lead to critical operational failures. The directive applies within the jurisdiction of the Civil Aviation Safety Authority (CASA), which is the regulatory body under the Commonwealth of Australia. The AD is effective from the date specified in the compliance section and requires adherence to the instructions and timelines outlined to maintain the airworthiness of the affected aircraft. The directive does not explicitly mention any exclusions or exemptions, implying that it applies universally to all specified aircraft within the mentioned serial number range. Subordinate instruments or further amendments may extend or modify the scope and requirements of this directive as needed.
Key Provisions
The Airworthiness Directive (AD) AD/LJ45/1 Amdt 1, issued by the Civil Aviation Safety Authority (CASA) under subregulation 39.1(1) of the Civil Aviation Safety Regulations 1998, pertains specifically to Learjet 45 Series aeroplanes with 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. This directive mandates two key actions to address the identified safety issues: the application of grease to the rotating disk assembly of the nose wheel squat switch mechanism and the replacement of the camrod of the nose wheel landing gear squat switch (Sections 1 and 2 of the Requirement).
The AD outlines specific obligations for the operators and maintenance personnel of the affected aircraft. Operators must ensure that the lubrication and replacement tasks are carried out in accordance with Bombardier Aerospace Service Information Letter SIL 32-016 dated 30 March 2000 and Bombardier SB 45-32-8 Revision 2 dated 14 March 2001, respectively. For Requirement 1, if the lubrication has not been completed as per the original directive, it must be completed within 30 days from the effective date of the amendment and repeated at intervals not exceeding 30 days until Requirement 2 is fulfilled. Requirement 2 necessitates the replacement of the camrod within 300 hours of time in service or 12 months after the effective date of the Amendment, whichever occurs first. Failure to comply with these requirements could result in significant safety risks, including the potential for the aircraft to depart from the runway at high speeds during landing due to uncommanded nose wheel angles.
Under this directive, non-compliance with the specified actions and timelines can lead to severe consequences. The AD does not explicitly mention penalties or specific legal consequences for non-compliance; however, such non-compliance could potentially lead to enforcement actions by CASA. These actions could include fines, grounding of the aircraft, or other regulatory penalties as determined by CASA, depending on the severity of the non-compliance and its impact on air safety. CASA retains the authority to take appropriate enforcement measures to ensure the safety and airworthiness of the aircraft in question.