AD/B747/112 - Main Entry Door Guide Arm

Overview

The Civil Aviation Regulations 1998, under Part 39, was enacted by the Parliament of Australia to regulate civil aviation safety and ensure compliance with international standards. Specifically, Airworthiness Directive AD/B747/112, dated 7/92, addresses the critical issue of potential bearing migration in the main entry door guide arm of Boeing 747 series aeroplanes, as identified by Boeing ASB 747-52A2237. This directive was introduced to address a safety concern raised by the Federal Aviation Administration (FAA) regarding insufficient bearing retention during production rework, which could lead to the inoperability of the emergency door power assist system and impede emergency evacuation procedures. The policy objective of this directive is to ensure aircraft safety by mandating specific actions to prevent such inoperability, with compliance required before 25 August 1992.

Scope and Application

The Civil Aviation Safety Authority (CASA) Schedule of Airworthiness Directives under the Civil Aviation Regulations 1998 applies to the Boeing 747 series aeroplanes, specifically those listed in Boeing ASB 747-52A2237, mandating compliance with the directives outlined in the referenced document. The primary purpose of these directives is to ensure the safety of passengers and crew by addressing issues such as the migrating guide arm assembly bearings that may result from insufficient bearing retention during production rework. Compliance with these directives is required for all Boeing 747 series aeroplanes, ensuring that any potential issues with the main entry door guide arm are rectified to prevent an inoperable emergency door power assist system and the inability to operate the door during an emergency evacuation. This directive, which corresponds to FAA AD 92-06-07 Amdt 39-8187, requires action to be taken prior to 25 August 1992. The regulatory framework is designed to extend the effective date required by the Federal Aviation Administration by approximately two months, ensuring that operators and maintenance providers have adequate time to comply with the safety measures stipulated in the directive.

Key Provisions

The Civil Aviation Regulations 1998, particularly Part 39 - 105, outlines the Civil Aviation Safety Authority's (CASA) Schedule of Airworthiness Directives for Boeing 747 series aeroplanes. Within this framework, AD/B747/112 addresses the main entry door guide arm, stipulating specific actions to be taken as per Boeing ASB 747-52A2237. This directive was prompted by a report of migrating guide arm assembly bearings potentially due to insufficient bearing retention during production rework, as referenced in FAA AD 92-06-07 Amdt 39-8187. The requirement is for compliance prior to 25 August 1992, ensuring that the specified actions prevent an inoperable emergency door power assist system and/or the inability to operate the door, which is crucial for emergency evacuation. The obligations imposed by this Act on the relevant parties, particularly operators of Boeing 747 series aeroplanes, are clear and direct. They must adhere to the actions detailed in Boeing ASB 747-52A2237 to ensure the safety and functionality of the main entry door guide arm. This includes verifying that the bearings are adequately retained and that the guide arm assembly is free from migration, thereby maintaining the operational integrity of the emergency door power assist system. Operators must ensure that these checks and corrective actions are completed before the compliance date of 25 August 1992. Failure to comply with the directives outlined in AD/B747/112 could lead to significant consequences. The potential for an inoperable emergency door power assist system poses a serious risk, particularly in emergency situations. The Act does not explicitly state penalties or consequences for non-compliance, but the inherent safety risks suggest that non-compliance could result in severe regulatory action, including grounding of the aircraft, fines, or other civil or criminal penalties as deemed appropriate by CASA. The gravity of ensuring the operational readiness of emergency systems underscores the importance of strict adherence to the requirements set forth in the Airworthiness Directive.