Overview

The Civil Aviation Safety Regulations 1998, enacted by the Commonwealth of Australia, address the need for stringent safety measures within the aviation industry. This legislation, issued by the Civil Aviation Safety Authority (CASA), is designed to ensure the airworthiness of aircraft and aeronautical products through various directives and safety regulations. The specific Airworthiness Directive (AD) AD/LJ45/5 issued under this regulation targets Learjet Model 45 aeroplanes with serial numbers 45-001 through 45-232, addressing a critical safety concern involving the horizontal stabiliser actuator assembly. This directive was introduced in response to a reported internal structural failure of the actuator assembly that could lead to excessive linear free play, potentially resulting in loss of control. The policy objective is to mandate inspections and necessary replacements to rectify unsafe conditions and ensure the continued safety of the aircraft in operation.

Scope and Application

The Civil Aviation Safety Regulations 1998, specifically Part 39 - 105, applies to the Learjet Model 45 aeroplanes with serial numbers ranging from 45-001 to 45-232 inclusive. This legislation mandates particular actions concerning the horizontal stabiliser actuator assembly to address identified safety issues. The requirement outlined in the directive is that an inspection must be conducted to ascertain the part number of the horizontal stabiliser actuator assembly, with subsequent replacement if certain part numbers are found to be installed. Additionally, the installation of specific part numbers as replacements is prohibited. This directive, issued by a delegate of the Civil Aviation Safety Authority, is effective as of its publication date of 21 March 2003, and compliance is mandatory before further flights post this date. The directive is applicable nationwide within Australia, falling under the Commonwealth’s regulatory purview.

Key Provisions

The Civil Aviation Safety Regulations 1998, specifically Part 39 - 105 under the Civil Aviation Safety Authority's Schedule of Airworthiness Directives, issue an Airworthiness Directive (AD) for Learjet Model 45 aeroplanes with serial numbers 45-001 through 45-232 inclusive. This directive, AD/LJ45/5, addresses the safety issue concerning the horizontal stabiliser actuator assembly (A66). The requirement section mandates that an inspection be conducted to determine the part number (P/N) of the horizontal stabiliser actuator assembly in accordance with the instructions in the Accomplishment Instruction of Bombardier Learjet Alert Service Bulletin (ASB) A45-27-15 dated 20 March 2003. If the inspection reveals that the installed actuator assembly has either P/N 6627401000-001 or 2A9200F, it must be replaced with a new actuator assembly P/N 6627401000-005 as per the same ASB instructions. Furthermore, the directive prohibits the installation of horizontal stabiliser actuator assembly with either P/N 6627401000-001 or 2A9200F on any aeroplane as a replacement part. The obligations imposed by this AD are primarily on the operators of Learjet Model 45 aeroplanes within the specified serial number range. Operators must conduct the required inspection to determine the part number of the installed horizontal stabiliser actuator assembly, as outlined in the Accomplishment Instruction of ASB A45-27-15. If the inspection identifies the specified part numbers, operators are required to replace the identified actuator assembly with the new part number 6627401000-005. Additionally, operators must ensure that the prohibited part numbers are not used for any replacement purposes. The directive mandates compliance with these requirements before further flight for inspections and replacements, and immediately for the prohibition of specified part numbers. Non-compliance with the provisions of this Airworthiness Directive can result in severe safety risks, as the directive was issued in response to a reported internal structural failure of the horizontal stabiliser actuator assembly that could lead to a possible loss of control of the aeroplane. While the regulations do not specify criminal or civil penalties for non-compliance with ADs, failure to adhere to the AD could result in the aircraft being deemed unairworthy by the Civil Aviation Safety Authority. Consequently, operators may face legal consequences, including fines or other enforcement actions, if the aircraft is found to be in non-compliance with the AD. Additionally, the safety risk associated with non-compliance could result in operational disruptions or grounding of the aircraft until the necessary actions are taken to rectify the situation.