AD/B737/4 Amdt 1 - Side of Body Rib

Overview

The Civil Aviation Regulations 1998, enacted by the Parliament of the Commonwealth of Australia, were introduced to ensure the safe and efficient operation of civil aviation in Australia. Part 39 - 105 of these regulations includes the Civil Aviation Safety Authority Schedule of Airworthiness Directives, which addresses specific safety concerns for various types of aircraft. One such directive pertains to Boeing 737 series aeroplanes, specifically addressing a recurring issue of cracking in the side of the body rib area, particularly the rib upper chord, skin, and BS 663.75 bulkhead fitting. This problem has been linked to localised cyclic stresses during approach and landing phases of flight. The policy objective of these directives is to enhance the safety and reliability of these aircraft by mandating specific maintenance and repair actions to mitigate the identified risks. The directive requires compliance with particular Federal Aviation Administration (FAA) and Boeing Service Bulletins, ensuring that all affected aircraft undergo the necessary inspections and repairs.

Scope and Application

The Civil Aviation Regulations 1998, specifically PART 39 - 105, applies to all Boeing 737 Series Aeroplanes and governs the airworthiness directives for this particular aircraft model. The applicability extends to Group A, which includes all model 737 aircraft with Line Numbers 1 to 433 plus 436 and 437, and Group B, which includes all model 737 aircraft with Line Numbers 434, 435 and 438 to 844. The regulation mandates compliance with specific FAA and Boeing directives to address reported cracking in the side of body rib area, particularly the rib upper chord, skin, and BS 663.75 bulkhead fitting. The geographic reach of these regulations is national, applying across the Commonwealth of Australia. Compliance requirements are detailed in the respective FAA and Boeing documents for each group of aircraft. The regulation does not explicitly state any exclusions, exemptions, or thresholds, suggesting a broad application to all specified aircraft within the given line numbers. The enforcement and interpretation of these regulations may be further elaborated through subordinate instruments, which would provide additional guidance on implementation and compliance.

Key Provisions

The Civil Aviation Regulations 1998, specifically Part 39 – 105, under the Civil Aviation Safety Authority (CASA) Schedule of Airworthiness Directives, governs the maintenance and operational standards for Boeing 737 Series aeroplanes. The applicable amendment, AD/B737/4 Amendment 1, focuses on the side of the body rib area, particularly addressing reported cracking in the rib upper chord, skin, and the BS 663.75 bulkhead fitting. These issues have been linked to localised cyclic stresses during approach and landing. The applicability of the directive is split into two groups: Group A includes all model 737 aircraft with Line Numbers 1 to 433, plus 436 and 437, while Group B includes all model 737 aircraft with Line Numbers 434, 435, and 438 to 844. For Group A aircraft, compliance is required with FAA AD 85-01-07, Amendment 39-4983, Sections A to E, and Boeing Service Bulletin 737-57-1087 Revision 4. This means that operators must adhere to the specific maintenance actions and inspection procedures detailed in these documents to ensure the structural integrity of the side of body rib area. For Group B aircraft, the requirement is to comply with FAA AD 85-22-02, Amendment 39-5159, Sections A to D, and Boeing Service Bulletin 737-57-1137 Revision 2, or as otherwise agreed upon by the Secretary. This directive also includes detailed instructions on the necessary actions to be taken to rectify the reported cracking issues. Operators of Boeing 737 aircraft must ensure that all maintenance and inspection activities are performed in accordance with the specified directives. This includes conducting thorough inspections to identify any signs of cracking in the designated areas, and implementing corrective actions as outlined in the relevant FAA airworthiness directives and Boeing service bulletins. Operators must maintain accurate records of all inspections and maintenance actions taken to ensure compliance with the regulatory requirements. Failure to comply with the airworthiness directives and service bulletins can result in serious consequences. Non-compliance with the regulations can lead to significant safety risks, including the potential for in-flight structural failure. The Civil Aviation Safety Authority has the authority to take enforcement actions against operators who fail to adhere to the compliance requirements. These actions may include fines, suspension or revocation of air operator certificates, and other regulatory penalties. The maximum penalties for non-compliance can be substantial, reflecting the serious nature of the safety issues addressed by the directives.