Overview

The Civil Aviation Safety Authority Act 1998 (CASA Act) was enacted to ensure the safety of civil aviation in Australia, providing the framework for the regulation of air navigation, aircraft certification, and airworthiness standards. This legislation was introduced to address the need for a robust regulatory system to manage aviation safety risks and ensure the protection of the public and the integrity of the aviation industry. The CASA Act empowers the Civil Aviation Safety Authority (CASA) to issue airworthiness directives, such as AD/B737/228, which was enacted to address safety concerns identified with specific aircraft models. This particular Airworthiness Directive was issued under the authority of the Civil Aviation Safety Authority to ensure that the identified unsafe condition is rectified, thereby maintaining the airworthiness of the affected Boeing 737 Series Aeroplanes. The policy objective of this directive is to mitigate potential fire hazards and ensure the continued safe operation of the specified aircraft models by requiring the replacement of the start converter units.

Scope and Application

This Airworthiness Directive applies to specific models of Boeing 737 aeroplanes, namely the 737-600, -700, -700C, -800, and -900 series, which are equipped with certain Honeywell Start Converter Units (SCU). The directive mandates the replacement of the SCU in the auxiliary power unit (APU) situated in the electrical and electronics compartment to prevent potential overheating, which could lead to an ignition source, fire, and damage to electrical wire bundles, thereby affecting the aeroplane's control systems. The replacement must be performed in accordance with approved methods detailed in the Boeing 737-600/700/800/900 Maintenance Manual and Aircraft Maintenance Manual, both dated in 2003 and 1998 respectively, and must be completed within 36 months from the effective date of the directive, which is 5 August 2004. The directive extends its jurisdiction throughout the Commonwealth of Australia, as indicated by its notification in the Commonwealth of Australia Gazette on 14 July 2004.

Key Provisions

This Airworthiness Directive (AD) issued by the Civil Aviation Safety Authority (CASA) delegate under subregulation 39.1(1) of the Civil Aviation Safety Regulations 1998 mandates specific actions to address safety concerns with certain Boeing 737 series aeroplanes. The AD applies to the Boeing 737-600, -700, -700C, -800, and -900 models equipped with start converter units (SCU) of certain Honeywell part numbers (sections 1 and 2). The primary requirement is to replace the SCU of the auxiliary power unit (APU) in the electrical and electronics (E/E) compartment. This replacement must adhere to the approved methods detailed in the Boeing 737-600/700/800/900 Maintenance Manual, Chapter 49-41-61, dated 5 June 1998, and the Aircraft Maintenance Manual, Chapter 49-41-61, dated 10 October 2003, as outlined in section 3. The directive specifies replacing existing Honeywell P/Ns with new ones, as listed in the compliance section. The compliance period for these actions is within 36 months from the effective date of the directive, which is 5 August 2004 (section 4). The AD imposes several obligations on the parties or entities it governs. Owners and operators of the specified Boeing 737 series aeroplanes must ensure that the replacement of the SCU is performed in accordance with the approved methods and within the specified timeframe. This includes conducting a thorough inspection of the APU SCU to identify the required replacement parts and executing the replacement using the approved Boeing manuals or equivalent procedures. Compliance with the directive is essential to maintain the airworthiness of the aircraft and to prevent potential overheating of the SCU's electrical connector, which could lead to fires in the E/E compartment and subsequent electrical failures (section 5). Failure to comply with the AD can result in significant consequences. Non-compliance could lead to the grounding of affected aircraft until the required actions are taken, potentially disrupting flight schedules and operations. From a regulatory perspective, the CASA delegate may take enforcement actions against non-compliant entities, which could include fines or other penalties. Additionally, operators who continue to fly non-compliant aircraft risk facing legal repercussions, including criminal charges if the non-compliance results in a safety incident. The specific penalties for non-compliance are not detailed in the AD, but they can be severe, reflecting the critical nature of the safety measures being mandated (section 6).