AD/CF6/39 - Accessory Gearbox Idler Adaptor - Inspection

Overview

The Civil Aviation Regulations 1998, enacted by the Australian Parliament, represent a comprehensive set of rules designed to ensure the safety of civil aviation within Australia. Part 39 of these regulations, specifically Section 106, addresses Airworthiness Directives, which are regulatory requirements intended to ensure the continued airworthiness of aircraft and related products. One such directive, AD/CF6/39, pertains to the inspection of accessory gearbox idler adaptors in General Electric Company CF6 80C2 series turbofan engines. This directive was introduced to address safety concerns associated with improper idler adapter inserts that could lead to serious incidents such as high-pressure fuel leaks and engine fires. The policy objective behind AD/CF6/39 is to enhance the safety of aviation operations by mandating specific inspection and replacement procedures for affected components, thereby preventing potential catastrophic failures.

Scope and Application

The Civil Aviation Regulations 1998, under the Commonwealth of Australia, specifically address the maintenance and safety of aircraft through various airworthiness directives. One such directive, AD/CF6/39, pertains to General Electric CF6 80C2 series turbofan engines that have specific accessory gearbox (AGB) idler adapters. The directive mandates a visual inspection of the AGB idler adapter inserts and the replacement of any adapters that do not meet serviceability standards. These engines are typically installed on aircraft such as Boeing 747 and 767, Airbus 300 and 310, and McDonnell Douglas MD-11 Series. However, the directive excludes engines repaired by GE Repair Document 032-273-S1 dated 18 April 1998, and only applies to those reworked from a P/N 9395M78G06 configuration using CF6-80C2 Service Bulletin 72-743 dated 25 August 1994. Compliance with this directive is mandatory, requiring inspections to be performed within 10 days of the directive's effective date and before further flight if replacements are necessary. This directive aims to prevent incidents such as the one where a fuel leak led to an engine fire, ensuring the continued safety and airworthiness of affected aircraft.

Key Provisions

The Civil Aviation Regulations 1998, under Part 39 - 106, include a specific airworthiness directive concerning the accessory gearbox (AGB) idler adaptors for General Electric Company CF6 80C2 series turbofan engines. This directive applies to those engines with a specific part number that have been reworked from an earlier configuration, excluding those repaired by a particular GE document dated April 1998. These engines are used in various aircraft types such as Boeing 747 and 767, Airbus 300 and 310, and McDonnell Douglas MD-11 Series. The directive mandates a visual inspection of the AGB idler adapter to ensure compliance with certain service bulletins and to identify any unserviceable inserts. Operators and maintenance providers must ensure that the visual inspection of the AGB idler adapter inserts is performed in accordance with the instructions detailed in the GE CF6-80C2 Alert Service Bulletin (ASB) 73-A283 Revision 2. If the inspection reveals any unserviceable inserts, the AGB adapters must be removed from service and replaced with serviceable parts that are flush with or extend past the back face of the casing. Compliance with these directives is crucial, with an initial deadline of 10 days from the effective date of the directive, and further requirements to be met before any subsequent flight if unserviceable inserts are found. Failure to comply with the provisions of this airworthiness directive can lead to significant consequences. The directive underscores the importance of adhering to the specified timelines and inspection protocols, as non-compliance can result in unsafe conditions leading to severe incidents such as fuel leaks and engine fires. This directive is a response to a reported incident where an improperly fitted AGB idler adapter led to a high-pressure fuel leak and subsequent engine fire, highlighting the critical nature of ensuring the integrity of these components. The directive is reflective of similar requirements issued by the United States Federal Aviation Administration (FAA).