AD/B767/69 Amdt 1 - Engine Bleed Air Crossover Duct

Overview

The Civil Aviation Regulations 1998, enacted by the Parliament of the Commonwealth of Australia, address the safety and operational standards of civil aviation in Australia. Specifically, Part 39 - 105 of these regulations, which pertains to the Civil Aviation Safety Authority Schedule of Airworthiness Directives, mandates directives to ensure the continued airworthiness of aircraft operating in Australian airspace. One such directive, AD/B767/69 Amendment 1, was introduced to address the issue of engine bleed air crossover duct failures in Boeing 767 series aeroplanes. The directive was necessitated by incidents where ruptures of the crossover bleed air duct led to loss of aircraft pressurisation, compromised hydraulic systems, and damage to air conditioning access panels, posing a significant risk of the aircraft descending into hazardous icing conditions without effective anti-icing capabilities. The policy objective of this amendment was to ensure that all affected aircraft are inspected and repaired before reaching critical operational thresholds, thereby enhancing flight safety. The legislative instrument F2006B03423, which pertains to the Civil Aviation Regulations 1998, was enacted to formalise these airworthiness directives and ensure compliance among operators of Boeing 767 series aircraft. This directive mandates that corrective actions must be taken according to Boeing's Airworthiness Service Bulletin 767-36A0041, with a compliance deadline set for either prior to 1 April 1993 or the accumulation of 7,000 flight cycles, whichever occurs later. Aircraft not engaged in ETOPS (Extended-range Twin-engine Operational Performance Standards) operations may qualify for an extension of these compliance requirements. The objective of this regulation is to mitigate the risk of catastrophic failures due to bleed air duct ruptures, thereby safeguarding passenger safety and aircraft integrity.

Scope and Application

The Civil Aviation Regulations 1998, specifically Part 39 - 105, applies to all Boeing 767 series aircraft within the jurisdiction of the Commonwealth of Australia. This regulation mandates compliance with the Airworthiness Directive AD/B767/69 Amendment 1 concerning the engine bleed air crossover duct. The requirement involves taking corrective action in accordance with Boeing ASB 767-36A0041, which must be implemented either prior to 1 April 1993 or after the aircraft has accumulated 7,000 flight cycles, whichever comes later. This directive was issued in response to incidents where the rupture of the crossover bleed air duct led to a loss of aircraft pressurisation, affecting the air driven hydraulic pump, wing thermal anti-icing, and causing damage to the air conditioning access panels. The failure of pressurisation may necessitate an emergency descent into potentially hazardous icing conditions without wing anti-icing capabilities. Notably, aircraft not engaged in ETOPS operations may qualify for an extension to the compliance requirements. The legislative instrument ensures that all applicable aircraft are maintained to a standard that prevents such critical failures, thereby enhancing flight safety.

Key Provisions

The Civil Aviation Regulations 1998, specifically Part 39 - 105, which pertains to the Civil Aviation Safety Authority’s (CASA) schedule of airworthiness directives, includes a directive (AD/B767/69) regarding Boeing 767 series aeroplanes (1). This airworthiness directive mandates that all Boeing 767 series aircraft must comply with certain requirements to ensure the safety of the aircraft during flight operations. The directive requires that, unless previously carried out, action must be taken in accordance with Boeing ASB 767-36A0041 (2). This action must be completed prior to 1 April 1993, or the accumulation of 7,000 flight cycles, whichever occurs later (3). For aircraft not engaged in ETOPS (Extended-range Twin-engine Operational Performance Standards) operations, there may be an extension to these compliance requirements (4). Entities governed by these regulations, primarily aircraft operators and maintenance providers, must ensure that the specified actions are implemented on all applicable Boeing 767 series aircraft. These obligations include conducting the required maintenance and modifications as per Boeing ASB 767-36A0041, ensuring that these are completed before the specified deadline, and maintaining appropriate records of compliance (5). Aircraft operators must verify that their maintenance schedules align with these directives to avoid any non-compliance issues. Failure to adhere to the provisions of this airworthiness directive can lead to serious safety risks, including potential aircraft pressurisation failure, which could result in forced descent into icing conditions without wing anti-icing capabilities, and damage to air conditioning access panels (6). The potential consequences of non-compliance include severe penalties. While the specific penalties are not detailed in the legislative instrument, non-compliance with airworthiness directives generally carries significant civil and criminal penalties, including fines and potential imprisonment, as these regulations are critical for ensuring the safety of air travel (7).