AD/B767/80 - Thrust Reverser System Flow Restrictors

Overview

The Civil Aviation Regulations 1998, administered by the Civil Aviation Safety Authority (CASA), were enacted to ensure safety in civil aviation and were established under the Civil Aviation Act 1988. A notable aspect of these regulations is Part 39, which contains the Airworthiness Directives (ADs) aimed at maintaining the airworthiness of aircraft. One such directive, AD/B767/80, specifically targets Boeing 767 series aeroplanes equipped with Pratt and Whitney JT9D-7R4 or General Electric CF6-80A series engines, addressing the issue of thrust reverser system flow restrictors. This directive was introduced to mitigate the risk of inadvertent thrust reverser deployment during flight, which could compromise aircraft controllability. Compliance with AD/B767/80 is mandatory, with a deadline of 31 January 1996, reflecting CASA's commitment to ensuring the highest safety standards in Australian civil aviation. The thrust reverser system flow restrictors directive, AD/B767/80, was formulated in response to reported instances of leakage across the actuator piston seals in Boeing 767 series aircraft. Such leakage posed a significant safety risk by potentially causing inadvertent deployment of the thrust reverser during flight, thereby reducing the aircraft's controllability. This AD mandates the replacement of existing flow restrictors with check valve restrictors, as outlined in Boeing Alert Service Bulletins 767-78-0064 and B767-78-0065 for the respective engine types. The directive was issued to ensure the continued safety and airworthiness of affected aircraft, in alignment with CASA's overarching policy objective to maintain and enhance the safety of civil aviation operations in Australia.

Scope and Application

The Civil Aviation Regulations 1998, specifically Part 39 - 105, pertains to Airworthiness Directives for Boeing 767 Series Aeroplanes, addressing the thrust reverser system flow restrictors. This legislation applies to all Boeing 767 series aircraft that are equipped with either Pratt and Whitney JT9D-7R4 or General Electric CF6-80A series engines. The directive mandates the replacement of existing thrust reverser system flow restrictor devices with check valve restrictors as per Boeing Alert Service Bulletin 767-78-0064 for aircraft with CF6-80A series engines and Alert Service Bulletin B767-78-0065 for those with P&W JT9D-7R4 series engines. The requirement aims to rectify issues where leakage across the actuator piston seals may lead to unintended deployment of thrust reversers during flight, potentially reducing the controllability of the aircraft. The compliance date set forth in the directive stipulates that these modifications must be completed by 31 January 1996 unless already performed. The directive extends its reach within the Commonwealth of Australia, governed by the Civil Aviation Safety Authority (CASA), ensuring adherence to safety standards and operational protocols for civil aviation.

Key Provisions

The Civil Aviation Regulations 1998, particularly Part 39 - 105 concerning the Civil Aviation Safety Authority's schedule of airworthiness directives, includes a directive (AD/B767/80) focused on Boeing 767 series aeroplanes. This directive applies to all Boeing 767 aircraft equipped with either Pratt and Whitney JT9D-7R4 or General Electric CF6-80A series engines (Section 11/94). The primary requirement of this directive is to replace the existing thrust reverser system flow restrictor devices with check valve restrictors. For aircraft with CF6-80A series engines, the replacement must be in accordance with Boeing Alert Service Bulletin 767-78-0064, while for those with P&W JT9D-7R4 series engines, it must follow Boeing Alert Service Bulletin B767-78-0065 (Section 11/94). This change aims to address reports of leakage across the actuator piston seals, which could potentially lead to an inadvertent deployment of a thrust reverser during flight, thereby reducing the controllability of the aircraft (Section 11/94). The directive imposes specific obligations on the operators and owners of Boeing 767 series aircraft equipped with the specified engines. These parties are required to ensure that the necessary modifications to the thrust reverser system flow restrictors are completed in line with the relevant Boeing Alert Service Bulletins. The directive stipulates that these modifications must be carried out unless they have already been completed prior to the directive's issue date (Section 11/94). Compliance with this directive is mandatory, and operators and owners must ensure that the required actions are taken no later than 31 January 1996 (Section 11/94). Failure to adhere to these requirements can result in safety risks and potential regulatory consequences. In terms of enforcement and compliance, any failure to comply with the provisions of AD/B767/80 may lead to serious safety implications. The directive is underpinned by the authority of the Civil Aviation Safety Regulations, and non-compliance could result in enforcement actions being taken by the Civil Aviation Safety Authority. While the specific penalties and consequences for non-compliance are not detailed in this particular directive, it is reasonable to infer that they could include fines, suspension or revocation of airworthiness certificates, and other regulatory measures as deemed necessary by the Authority to ensure compliance and maintain safety standards (Section 11/94). The directive also references FAA AD 94-14-01, indicating alignment with international safety standards and the collaborative nature of aviation safety regulations across jurisdictions.