AD/B737/103 - Rudder Power Control Unit Replacement

Overview

The Civil Aviation Regulations 1998, specifically under Part 39 - 105, was enacted by the Australian Parliament to ensure the safety and regulation of civil aviation. The Boeing 737 Series Aeroplanes Airworthiness Directive AD/B737/103, which mandates the replacement of the rudder power control unit (PCU) to prevent cracking and seizing of the internal summing lever assembly bearing, was introduced to address a critical safety issue identified by the Federal Aviation Administration (FAA). This directive aims to rectify the problem caused by the installation of an incorrect bolt, which could potentially lead to bearing failure and uncommanded rudder movements. The directive, which became effective on 1 April 1997, requires compliance within 90 days to ensure the continued airworthiness and safety of Boeing 737 series aeroplanes operating under Australian certification. The Civil Aviation Safety Authority (CASA) has adopted this directive to align with FAA AD 97-05-10, reflecting a collaborative approach to aviation safety. The policy objective behind this legislative measure is to prevent potential hazards that could compromise flight safety, ensuring that all model 737 aeroplanes equipped with the identified rudder PCU undergo the necessary replacement to mitigate the risk of bearing failure. The directive underscores the importance of adhering to manufacturer specifications and the rigorous oversight required to maintain the highest safety standards in civil aviation.

Scope and Application

The Civil Aviation Regulations 1998, specifically Part 39 - 105, applies to all Boeing 737 series aeroplanes that are certificated in any category and possess a main rudder power control unit (PCU) identified in Boeing Service Letter 737-SL-27-112-B dated February 6, 1997. The directive mandates the removal and replacement of the main rudder PCU to prevent cracking and seizing of the internal summing lever assembly bearing, thereby ensuring continued airworthiness. This directive is effective from 1 April 1997, with a compliance requirement to be completed within 90 days of the directive's effective date. The directive is issued in response to a reported incident of bearing cracking caused by the incorrect installation of a Hi-Lock bolt instead of the correct specification bolt, which could lead to uncommanded rudder movement. The directive does not specify exclusions or exemptions but ensures that all affected aircraft undergo the necessary maintenance actions to prevent potential safety hazards.

Key Provisions

The Civil Aviation Regulations 1998, specifically Part 39 - 105, detail the requirements and procedures for maintaining the airworthiness of aircraft in Australia. In this context, AD/B737/103 pertains to Boeing 737 series aeroplanes and mandates the replacement of the main rudder power control unit (PCU). The directive (section 6) applies to all model 737 aeroplanes that have a main rudder PCU identified in Boeing Service Letter 737-SL-27-112-B dated February 6, 1997, regardless of their certificate category. The primary requirement is to replace the existing PCU with a serviceable unit to prevent cracking and seizing of the internal summing lever assembly bearing, as per Boeing Service Letter 737-SL-27-112-B (section 6). This replacement must be completed within 90 days from the effective date of the directive, which is April 1, 1997 (section 6). The directive references FAA AD 97-05-10 for further information (section 6). Compliance with AD/B737/103 involves specific obligations for the parties governed by this legislation. Operators and maintenance providers of Boeing 737 aeroplanes must ensure that the main rudder PCU is replaced as directed. This includes identifying the affected PCUs, removing them from service, and replacing them with the correct units. The directive necessitates adherence to the procedures outlined in Boeing Service Letter 737-SL-27-112-B, ensuring that all technical specifications and instructions are followed accurately. Failure to comply with these requirements may result in the aeroplane being deemed unairworthy, thereby exposing the operator to legal consequences and potential safety hazards. The Civil Aviation Regulations 1998 impose significant consequences for non-compliance with AD/B737/103. Operators and maintenance providers who fail to replace the main rudder PCU within the stipulated timeframe may face severe penalties. The Civil Aviation Safety Authority (CASA) can issue enforcement actions, including fines and sanctions, against entities that do not adhere to the directive. In cases of severe non-compliance, CASA may suspend or revoke the certificate of airworthiness of the affected aeroplane, effectively grounding it until the required modifications are completed. Furthermore, any resulting accidents or incidents caused by non-compliance with this directive could lead to criminal charges against the responsible parties, potentially resulting in substantial penalties and imprisonment.