AD/SF340/72 - MLG Hydraulic Swivel Brackets

Overview

The Civil Aviation Regulations 1998, enacted by the Australian Government, establish comprehensive standards and requirements for airworthiness, among other aviation-related matters. One of the legislative instruments under this regulation is the Airworthiness Directive AD/SF340/72, which was introduced to address the specific issue of hydraulic swivel bracket failures in SAAB SF340 series aeroplanes. This directive targets the misalignment of downlock or brake swivels in the main landing gear, which has led to an abnormally high failure rate of hydraulic swivels and consequent loss of hydraulic systems. The policy objective of this directive is to ensure the safety of aircraft operations by mandating corrective actions in accordance with the specified service bulletin, thereby preventing potential safety hazards arising from the identified structural issues. The directive was made effective on 7 October 1999 and required compliance by 2 July 2000. The Australian Parliament enacted this regulation to provide a structured framework for the oversight and maintenance of civil aviation safety. The specific directive AD/SF340/72 was issued by the Civil Aviation Safety Authority to mandate corrective actions for the identified problem, ensuring that the safety of SAAB SF340 series aeroplanes is maintained by addressing the risk of hydraulic swivel failures. Compliance with this directive is critical to prevent the identified failures that could compromise the integrity and safety of the aircraft's hydraulic systems.

Scope and Application

The Civil Aviation Regulations 1998, specifically Part 39 - 105, applies to the Saab SF340 Series aeroplanes, which includes Model SF340A aircraft with serial numbers ranging from 004 to 159, and Model 340B aircraft with serial numbers from 160 to 339. This regulation mandates compliance with SAAB Aircraft AB Mandatory Service Bulletin 340-29-009 Revision 2, dated 2 July 1999, which outlines the necessary action to address issues such as misalignment of the downlock or brake swivels in the main landing gear dragbrace and shock strut trunnions. These issues have been linked to excessive loads during the extension and retraction of the landing gear, leading to a high failure rate of the hydraulic swivels and subsequent loss of hydraulic systems. Compliance with this directive is required before 2 July 2000, and it became effective on 7 October 1999, applying across the Commonwealth of Australia under the jurisdiction of the Civil Aviation Safety Authority.

Key Provisions

The Civil Aviation Regulations 1998, specifically Part 39 - 105, addresses airworthiness directives pertaining to certain aircraft models. For instance, AD/SF340/72 (10/99) mandates the compliance of SAAB SF340 Series aeroplanes, including models SF340A with serial numbers 004 through 159 and SF340B with serial numbers 160 through 339. This directive requires that actions be taken in accordance with SAAB Aircraft AB Mandatory Service Bulletin 340-29-009 Revision 2, dated 2 July 1999 (Section 1). This service bulletin pertains to the hydraulic swivel brackets in the main landing gear (MLG) and is referenced in LFV AD 1-145. The directive emphasises that compliance must be achieved before 2 July 2000. Entities governed by this airworthiness directive must ensure that the specified modifications and inspections are carried out on the MLG hydraulic swivel brackets of the affected aircraft models. This involves rectifying any misalignment of the downlock or brake swivels in the MLG dragbrace and shock strut trunnions. The directive mandates that these changes be implemented to mitigate the excessive loads that have led to a high failure rate of the hydraulic swivels and subsequent loss of hydraulic systems. The directive became effective on 7 October 1999, setting a clear timeline for compliance. Failure to comply with the requirements outlined in AD/SF340/72 (10/99) can lead to serious consequences. The Civil Aviation Regulations 1998 provide for both civil and criminal penalties for non-compliance with airworthiness directives. Specifically, breaches of these directives may result in fines or imprisonment. The severity of the penalties can vary, but they are designed to enforce strict adherence to safety standards. Operators who fail to comply with the mandated service bulletin risk compromising the safety and airworthiness of their aircraft, leading to potential accidents and endangering lives.