Overview

The Civil Aviation Regulations 1998 (CAR 1998) form a key part of the legislative framework governing civil aviation in Australia. Enacted by the Australian Government, these regulations address safety and operational standards for aircraft and aeronautical products. Among the many provisions within the CAR 1998, Part 39 specifically pertains to airworthiness directives, which are legally binding instructions issued by the Civil Aviation Safety Authority (CASA) to ensure the continued airworthiness of aircraft. The objective of these directives is to mitigate risks to safety by mandating specific actions when unsafe conditions are identified. For instance, Airworthiness Directive AD/B747/273 pertains to Boeing 747 Series Aeroplanes and was introduced to address a safety issue related to thrust reverser sleeve actuator piston seal leakage, which could potentially lead to uncommanded in-flight deployment of the thrust reverser. This directive requires the replacement of certain flow restrictors to enhance safety, and it was issued under the authority granted by the CAR 1998 to CASA to ensure compliance with safety standards.

Scope and Application

The Airworthiness Directive (AD) issued by the Civil Aviation Safety Authority (CASA) under the Civil Aviation Regulations 1998 applies specifically to Boeing 747-400 series aeroplanes, up to and including line position 1022, which are powered by Pratt and Whitney PW 4000 series engines. The directive mandates the replacement of thrust reverser flow restrictor devices with one-way (check) valve restrictors to address issues of thrust reverser sleeve actuator piston seal leakage. This action is necessary to mitigate the risk of uncommanded in-flight deployment of a thrust reverser, as identified by Boeing through their Alert Service Bulletin 747-78A2128. The compliance requirement is that the specified action must be completed before further flight. The AD is effective from 11 July 2002, following its notification in the Commonwealth of Australia Gazette on 19 June 2002. This regulatory action is part of the broader framework under which CASA ensures airworthiness standards are met to maintain safety in civil aviation across the nation.

Key Provisions

The Airworthiness Directive (AD) outlined in the Civil Aviation Regulations 1998 (CAR) addresses a specific safety issue related to Boeing 747-400 series aeroplanes powered by Pratt and Whitney PW 4000 series engines. This directive, identified as AD/B747/273, mandates that the thrust reverser flow restrictor devices on these aeroplanes must be replaced with one-way (check) valve restrictors as specified in Boeing Alert Service Bulletin 747-78A2128 or its Revision 1 (sections 105(a), (b), and (c)). This change is crucial to prevent potential in-flight uncommanded deployment of the thrust reverser, which could arise from significant leakage in the thrust reverser sleeve actuator piston seals. The requirement to undertake this action is mandated prior to any further flight of the affected aircraft (section 105(a)). Operators of the Boeing 747-400 series aeroplanes specified in the AD are obligated to comply with the directive by replacing the thrust reverser flow restrictors as per the instructions given. This directive applies to aeroplanes up to and including line position 1022. The compliance with the AD is mandatory, and any further flight of the aeroplanes must be preceded by the required modifications to ensure airworthiness and safety (section 105(a), (b), and (c)). Failure to comply with this Airworthiness Directive can lead to serious safety concerns, including potential in-flight deployment of the thrust reverser, which could result in severe consequences. The Civil Aviation Regulations 1998 do not specify particular penalties for non-compliance with ADs; however, non-compliance could lead to enforcement actions by the Civil Aviation Safety Authority (CASA). These actions may include grounding of the aircraft, legal proceedings, or other regulatory actions deemed necessary to ensure compliance and safety. The severity of the consequences depends on the extent of non-compliance and the associated risk to aviation safety (section 105(a), (b), and (c)).