AD/B737/55 - APU Power Feeder Cable Bundle Chafing

Overview

The Civil Aviation Regulations 1998 (Cth) were enacted to provide a comprehensive framework for the regulation of civil aviation in Australia, ensuring the safety and efficiency of air travel. Part 39, specifically addressing airworthiness directives, was introduced to maintain aircraft in a condition that ensures safe operation. This part of the regulation was established to address potential safety hazards and ensure compliance with international aviation safety standards. The Civil Aviation Safety Authority (CASA) is the enacting body responsible for enforcing these regulations, aiming to mitigate risks and uphold the highest safety standards in Australian civil aviation. The policy objective behind these regulations is to protect passengers, crew, and the general public by mandating that all aircraft meet stringent safety criteria, thereby preventing accidents and enhancing overall aviation safety. The specific airworthiness directive AD/B737/55, concerning Boeing 737 series aeroplanes, was introduced to address an identified risk related to the APU power feeder cable bundle chafing, which could potentially lead to an oxygen-fed fire due to electrical arcing. The directive requires compliance with the technical requirements outlined in FAA AD 90-25-12, with a revised effectivity date of 18 April 1991 for Australian registered aircraft. Boeing identified insufficient clearance between the APU power feeder cable, crew oxygen system tubing, and horizontal stabiliser trim control cables, necessitating corrective action to prevent any safety incidents. CASA's role is to ensure that these directives are implemented effectively, maintaining the airworthiness of aircraft and safeguarding those involved in aviation activities.

Scope and Application

The Civil Aviation Regulations 1998, specifically Part 39 - 105, applies to all Boeing 737 series aeroplanes listed in Boeing Service Bulletin 737-35-1033 dated 15 March 1990, mandating compliance with Airworthiness Directive (AD) AD/B737/55. This regulation is enforced by the Civil Aviation Safety Authority and pertains to aircraft registered in Australia, thereby extending its reach across the Commonwealth. The AD requires action in accordance with the technical requirements of Federal Aviation Administration (FAA) AD 90-25-12, with a revised effectivity date of 18 April 1991 for Australian-registered aircraft. The directive addresses the risk of an oxygen-fed fire caused by insufficient clearance between the APU power feeder cable, the crew oxygen system tubing, and the horizontal stabiliser trim control cables. Compliance must be achieved as specified in the relevant requirement document, and Boeing Service Bulletin 737-35-1033 also refers to this issue. This legislation ensures that all applicable aircraft meet stringent safety standards to prevent potential hazards associated with cable chafing and electrical arcing.

Key Provisions

The main operative sections of this legislation, specifically Civil Aviation Regulations 1998, Part 39 - 105, focus on ensuring the airworthiness of Boeing 737 series aeroplanes, particularly addressing an issue with the APU power feeder cable bundle chafing. Section 39.105 outlines the applicability of the Airworthiness Directive (AD) to all Boeing 737 series aeroplanes mentioned in Boeing Service Bulletin (SB) 737-35-1033 dated 15 March 1990. The requirement section stipulates compliance with the technical requirements outlined in FAA AD 90-25-12, with a specific effectivity date of 18 April 1991 for Australian registered aircraft. The directive mandates corrective actions to prevent potential chafing and subsequent electrical arcing that could lead to an oxygen-fed fire. The obligations imposed by this legislation on the parties or entities it governs primarily involve adhering to the specified technical requirements and ensuring that corrective actions are implemented in accordance with the requirements document. This includes conducting inspections and making necessary repairs to the APU power feeder cable bundle to prevent any chafing issues that could compromise the safety of the aircraft. Operators of Boeing 737 series aeroplanes must ensure that all personnel involved in maintenance and inspection activities are properly trained and qualified to perform the required tasks. Furthermore, operators are required to maintain comprehensive records of all actions taken to comply with the AD, including documentation of inspections, repairs, and any non-compliance issues that arise. The consequences of breaching the provisions of this legislation can be severe. Civil Aviation Safety Authority (CASA) may take enforcement action against operators who fail to comply with the AD, which could include fines, suspension of operations, or other regulatory penalties. Under Australian law, non-compliance with airworthiness directives can result in civil penalties, including fines up to $132,000 for individuals and significantly higher amounts for corporations, as well as potential criminal charges. In addition to financial penalties, operators may face reputational damage and increased scrutiny from regulatory authorities, which could impact their ability to conduct business and maintain the airworthiness of their aircraft fleet.