AD/B747/131 - Flap Control Unit Wiring Change

Overview

The Civil Aviation Regulations 1998, as amended by the instrument F2006B03033, contain provisions aimed at enhancing the safety of civil aviation, particularly addressing issues related to the airworthiness of specific aircraft models. This legislative instrument, administered by the Civil Aviation Safety Authority, targets the Boeing 747 Series aeroplanes, focusing on the flap control unit wiring for certain model 747-400 aircraft. The enactment of this regulation responds to safety concerns identified by the Federal Aviation Administration (FAA) regarding the disconnection of electrical connectors in the Landing Gear Module, which can lead to the loss of flap control, potentially resulting in hazardous flight conditions. The policy objective is to mandate a wiring revision to mitigate these risks, ensuring compliance with the specified standards to prevent incidents such as an all-up-flaps landing.

Scope and Application

The Civil Aviation Regulations 1998, specifically Part 39 - 105, under the Civil Aviation Safety Authority's Schedule of Airworthiness Directives, pertains to Boeing 747 Series Aeroplanes and mandates a wiring change for the Flap Control Unit (FCU) for particular aircraft models. The directive AD/B747/131 applies to Boeing 747-400 aircraft with specific line numbers, namely those ranging from 696 through 1019 and from 1021 through 1026. The requirement involves revising the FCU input wiring in accordance with Boeing Alert Service Bulletin 747-27A2346 Revision 1 dated 19 May 1994. This directive is closely aligned with FAA AD 94-14-21 Amendment 39-8970, reflecting a coordinated approach in addressing safety concerns across jurisdictions. Compliance with this directive is essential to mitigate the risk of flap control failure, which could lead to a significant operational hazard, specifically the potential for an all-up-flaps landing. The directive necessitates that the specified wiring change be completed before 1 December 1994 to ensure adherence to safety standards and prevent the disconnection of Landing Gear Module electrical connectors that could result in a loss of flap control.

Key Provisions

The main operative sections of this legislative instrument are AD/B747/131, which pertains to the wiring change of the Flap Control Unit (FCU) for Boeing 747 Series Aeroplanes, specifically the 747-400 models with line numbers ranging from 696 to 1019 and 1021 to 1026 (section 1). This directive mandates that the FCU input wiring must be revised in accordance with Boeing Alert Service Bulletin 747-27A2346 Revision 1 dated 19 May 1994, and it references FAA AD 94-14-21 Amdt 39-8970 (section 2). Compliance with this directive is required before 1 December 1994 (section 3). The obligations imposed by this Act on the relevant parties, such as aircraft operators and maintenance organisations, include ensuring that the specified wiring modifications are carried out as per the detailed instructions in Boeing Alert Service Bulletin 747-27A2346 Revision 1. Operators must verify that the wiring changes have been completed on the designated aircraft models before the specified deadline. This requirement is essential to maintain the safety and airworthiness of the aircraft, specifically to mitigate the risk of flap control failures leading to an all-up-flaps landing (section 4). Breach of these obligations may lead to serious consequences. Although the specific penalties for non-compliance are not explicitly stated in the text, failure to adhere to airworthiness directives can result in significant civil or criminal penalties under the Civil Aviation Act 1988 and the Civil Aviation Regulations 1988. Such penalties may include fines, suspension or revocation of an operator's certificate, and potential criminal charges if the non-compliance results in an accident or serious incident (section 5). The exact penalties would depend on the severity of the breach and the impact on aviation safety.