AD/B747/159 - Forward Pressure Bulkhead

Overview

The Civil Aviation Regulations 1998, specifically Part 39, were enacted to provide comprehensive rules for civil aviation safety in Australia, addressing the need for stringent oversight and regulation of aviation activities. Within this framework, the Civil Aviation Safety Authority issued Airworthiness Directive AD/B747/159 to address the identified issue of cracks in the forward pressure bulkhead of Boeing 747 Series aeroplanes. This legislation was introduced to mitigate the safety risks posed by the structural integrity of the forward pressure bulkhead, which had shown signs of fatigue due to cyclic pressure loads. The objective of this directive is to mandate regular inspections and, where necessary, modifications or repairs to ensure the continued airworthiness of the affected aircraft. The enforcement of this directive by the Civil Aviation Safety Authority aims to maintain high safety standards in civil aviation by proactively addressing potential structural failures. The directive applies to all model 747s, line numbers 1 to 886, excluding 80, 85, and 151. The requirement involves inspecting the forward pressure bulkhead structure in accordance with Boeing Service Bulletin 747-53-2355, which supersedes previous Bulletin 747-53-2210. Compliance necessitates inspections at specified flight thresholds and intervals, with additional inspections required for aircraft that exceed these flight thresholds. Notably, flights where the cabin pressure differential does not exceed 2.0 psi are excluded from the count. This directive underscores the importance of regular maintenance and vigilance in ensuring the structural safety of commercial aircraft.

Scope and Application

The Civil Aviation Regulations 1998, under the Australian Civil Aviation Act 1988, apply to all model 747 Boeing aeroplanes, specifically those with line numbers 1 to 886, with the exceptions of line numbers 80, 85, and 151. These regulations mandate inspections of the forward pressure bulkhead structure in accordance with Boeing Service Bulletin 747-53-2355, which supersedes the previous Boeing Service Bulletin 747-53-2210. Compliance requires inspections to be conducted at the flight thresholds and intervals specified in the relevant Service Bulletin, with aircraft that have surpassed these thresholds needing inspection within 500 flights after 18 July 1996. It is noteworthy that flights during which the cabin pressure differential does not exceed 2.0 psi are excluded from the count. Modifications or repairs of specific areas in compliance with Boeing SB 747-53-2355 negate the need for inspections of those areas. These regulations extend across the Commonwealth of Australia, overseen by the Civil Aviation Safety Authority, and apply to all operators and entities involved in the maintenance and operation of Boeing 747 aircraft within the country.

Key Provisions

The primary operative section of this legislation, AD/B747/159 (paragraph 1), pertains to the inspection and modification of the forward pressure bulkhead of Boeing 747 Series aeroplanes, specifically those with line numbers 1 to 886, excluding 80, 85, and 151. The requirement (paragraph 2) mandates that the forward pressure bulkhead structure be inspected in accordance with Boeing Service Bulletin 747-53-2355. It is important to note that this Service Bulletin supersedes Boeing SB 747-53-2210, and the inspections must be conducted at the flight thresholds and intervals specified in Paragraph D of the bulletin (paragraph 3). Aircraft that have surpassed these specified flight thresholds must be inspected within 500 flights after 18 July 1996. Additionally, any modification or repair of the affected areas in accordance with Boeing SB 747-53-2355 will cancel the inspection requirements for those specific areas (paragraph 4). The Act imposes specific obligations and requirements on the parties or entities it governs. Operators and owners of Boeing 747 Series aeroplanes must ensure that the forward pressure bulkhead is inspected in accordance with the specified Boeing Service Bulletin (paragraph 5). This involves adhering to the prescribed flight thresholds and intervals (paragraph 6). Moreover, operators must ensure that any modifications or repairs are carried out in line with the instructions provided in Boeing SB 747-53-2355 (paragraph 7). It is also worth noting that flights on which the cabin pressure differential does not exceed 2.0 psi need not be counted towards the inspection requirements (paragraph 8). Failure to comply with the provisions of this legislation can result in significant consequences. While the specific offences, penalties, or consequences for breach are not detailed in the provided text, it is known that breaches of Civil Aviation Regulations can lead to both civil and criminal liabilities (paragraph 9). In general, penalties for non-compliance with civil aviation regulations can include fines, suspension or revocation of operating permits, and other regulatory sanctions (paragraph 10). In more severe cases, criminal charges may be pursued, leading to imprisonment and substantial fines (paragraph 11). The exact penalties would depend on the specific nature and severity of the breach, as well as the jurisdiction in which the offence occurred (paragraph 12).