AD/B747/177 - Upper Deck Floor Beam at Sta. 980

Overview

The Civil Aviation Regulations 1998, which were enacted by the Australian Parliament, regulate various aspects of civil aviation safety, including the issuance of airworthiness directives. One such directive, AD/B747/177, was introduced to address the issue of extensive corrosion at station (STA) 980 in the upper deck floor beam of Boeing 747-300 and -400 series aeroplanes, particularly those modified to a stretched upper deck configuration and equipped with an upper deck cart lift. The problem identified by the Federal Aviation Administration (FAA) was that the corrosion could lead to fatigue cracking of the floor beam, potentially resulting in structural failure, extensive damage, and rapid decompression of the aircraft. The airworthiness directive aims to ensure compliance with the technical inspection requirements to mitigate these risks, as outlined in FAA AD 97-09-13 Amdt 39-10009, with references to Boeing Service Bulletins 747-53-2327 and 747-53A2400. This directive became effective on 14 August 1997.

Scope and Application

The Civil Aviation Regulations 1998, specifically under PART 39 - 105, addresses airworthiness directives for ensuring the safety of civil aviation within Australia. This legislative instrument applies to Boeing 747 Series Aeroplanes, including Model 747-300 and -400 series aircraft with line numbers up to and including 843, as well as Model 747 series aircraft modified to a stretched upper deck configuration where an upper deck cart lift has been installed at station (STA) 980. The directive mandates that these aircraft undergo inspections to comply with the technical requirements set forth by FAA AD 97-09-13 Amdt 39-10009, referencing Boeing Service Bulletins 747-53-2327 and 747-53A2400. The directive became effective on 14 August 1997, with compliance required unless the specified inspection was already completed by the effective date. This regulation ensures that any identified risks of structural failure due to corrosion and potential fatigue cracking at STA. 980 are mitigated, thereby safeguarding the integrity and safety of the aircraft.

Key Provisions

The Civil Aviation Regulations 1998, specifically Part 39 - 105, includes a Schedule of Airworthiness Directives that governs the safety requirements for certain aircraft models. One such directive, AD/B747/177, pertains to Boeing 747 Series Aeroplanes, particularly the upper deck floor beam at station (STA) 980. This directive applies to Model 747-300 and -400 series aircraft with line numbers up to and including 843, as well as Model 747 series aircraft modified to a stretched upper deck configuration that have an upper deck cart lift installed at STA 980 (Section 1). The key requirement of this directive is that the upper deck floor beam at STA 980 must be inspected according to the technical specifications outlined in FAA AD 97-09-13 Amdt 39-10009. The inspection must be carried out unless it has already been completed, as specified in the requirement document, with a revised effective date of 14 August 1997 (Section 2). Boeing Service Bulletins 747-53-2327 and 747-53A2400 provide additional reference material related to the inspection process. Operators of the affected aircraft are obligated to ensure that the inspection is conducted by qualified personnel and that any identified issues are rectified promptly to maintain the airworthiness of the aircraft. Failure to comply with this directive could compromise the structural integrity of the aircraft and pose significant safety risks. This directive became effective on 14 August 1997, meaning that compliance was required from that date onwards. Non-compliance with the airworthiness directive could result in serious safety hazards. The Federal Aviation Administration (FAA) received reports of extensive corrosion at STA 980, and analysis indicated that fatigue cracking in this area could lead to the beam breaking. This, in turn, could cause extensive damage to adjacent structures and potentially result in rapid decompression of the aircraft. The Civil Aviation Safety Authority (CASA) and the FAA have the authority to enforce compliance, and penalties for non-compliance could include grounding of the aircraft, fines, and other enforcement actions as deemed necessary to ensure safety standards are met.