AD/IAI-W/18 Amdt 1 - Horizontal Stabiliser Trim Actuator

Overview

The Civil Aviation Regulations 1998, enacted by the Parliament of Australia, establish the framework for ensuring the safety of civil aviation within the country. Specifically, Part 39 - 105 Civil Aviation Safety Authority Schedule of Airworthiness Directives addresses the need for detailed and specific airworthiness directives to ensure the safety of aircraft operations. The legislative instrument F2006B10793, concerning Israel Aircraft Industries 1123 and 1124 (Westwind) Series Aeroplanes, is an example of such a directive. This particular instrument, effective from 3 February 1998, was introduced to address safety concerns identified in the horizontal stabiliser trim actuator of these aircraft models, following an incident where a jackscrew failure was discovered. The policy objective is to mandate specific maintenance actions to prevent similar failures, ensuring the continued airworthiness and safety of these aircraft.

Scope and Application

The Civil Aviation Regulations 1998, specifically Part 39 - 105, includes an Airworthiness Directive concerning the Israel Aircraft Industries 1124 and 1124A (Westwind) series aeroplanes, focusing on the horizontal stabiliser trim actuator. This legislation applies to all models 1124 and 1124A aircraft, irrespective of their serial numbers. The directive mandates adherence to Israel Aircraft Industries Service Bulletins 1124-27-133 and 1124-27-136, which entail inspections and the overhaul or replacement of the Horizontal Stabiliser Trim Actuator. Compliance with these requirements is contingent on the aircraft's landing count and service hours post-2 October 1996, with specific actions mandated if either 6,000 landings or 2,000 landings, or both, have been reached within 50 hours of service. The directive also refers to Israel CAA AD 27-97-09-02 and AD 96-92, and compliance must be achieved by 26 August 1999, unless already completed. This directive is a response to findings of a sheared horizontal stabiliser jackscrew and aims to ensure the airworthiness of the affected aircraft by replacing parts with unknown histories or expired fatigue life.

Key Provisions

The Civil Aviation Regulations 1998, specifically Part 39 - 105, outlines the Civil Aviation Safety Authority (CASA) Schedule of Airworthiness Directives, including the requirements for Israel Aircraft Industries (IAI) 1123 and 1124 (Westwind) Series Aeroplanes as detailed in AD/IAI-W/18 Amendment 1. This amendment, effective from 3 March 1998, focuses on the horizontal stabiliser trim actuator, which experienced a jackscrew failure. The directive applies to all models 1124 and 1124A aircraft regardless of their serial number. The primary requirement, as stated in the directive, involves taking action in accordance with IAI Service Bulletin 1124-27-133 and overhauling and replacing the horizontal stabiliser trim actuator as per IAI Service Bulletin 1124-27-136. It is important to note that replacing the trim actuator under Requirement 2 terminates the inspections mandated by Requirement 1. Additionally, Israel's Civil Aviation Authority (CAA) AD 27-97-09-02 and AD 96-92 are referenced. The compliance requirements of the AD/IAI-W/18 Amendment 1 mandate that aircraft and actuators that have achieved either 6,000 landings or 2,000 landings respectively, within 50 hours of time in service after 2 October 1996, must adhere to the directive's requirements. For aircraft with fewer landings, the directive applies at the next inspection for maintenance release after 2 October 1996. Moreover, all compliance actions must be completed before 26 August 1999, unless already accomplished. Subsequent compliance follows the Maintenance Manual Chapter 5. The initial requirement remains unchanged from the original directive, which became effective on 7 November 1996. The AD/IAI-W/18 Amendment 1 was issued in response to an inspection where a horizontal stabiliser jackscrew was found to be sheared, resulting in the rod end separating from the jackscrew. This amendment initiates a program for the removal from service of units with expired fatigue life or unknown history and mandates their replacement with new, life-controlled jackscrews. This action is a critical safety measure to prevent potential catastrophic failures during flight. Breaches of the AD/IAI-W/18 Amendment 1 may result in civil or criminal consequences. Operators failing to comply with the directive risk compromising the airworthiness of the aircraft, potentially leading to severe penalties. The Civil Aviation Regulations 1998 impose obligations on aircraft operators to ensure compliance with all applicable airworthiness directives. Failure to meet these obligations can result in enforcement actions by CASA, including fines, suspension or revocation of air operator certificates, and potential criminal charges against responsible individuals. The specific penalties for non-compliance are detailed in the Civil Aviation Act 1988, with the maximum penalties varying depending on the severity and intent of the breach.