AD/SF340/69 Amdt 1 - MLG Support Assembly Bearing Housings

Overview

The Civil Aviation Regulations 1998, enacted by the Parliament of Australia, govern various aspects of civil aviation safety, including the implementation of Airworthiness Directives (ADs). One such AD, issued by the Civil Aviation Safety Authority (CASA), is AD/SF340/69 Amendment 1, which addresses corrosion issues in the Saab SF340 Series Aeroplanes' main landing gear support assembly bearing housings. This directive was introduced to ensure the continued airworthiness and safety of these aircraft by mitigating the risks associated with corrosion, which can lead to fatigue cracks and compromised structural integrity. The policy objective behind this amendment is to enhance safety standards and comply with international safety directives, particularly those issued by the Swedish aviation authorities following their discovery of similar issues. Amendment 1 to AD/SF340/69 became effective on 31 December 1999, and it mandates specific inspection and maintenance actions for Saab SF340A and SF340B models within defined flight cycle parameters. The directive requires inspections and repairs based on the aircraft's total flight cycles and specific intervals post the amendment's effective date. This proactive approach aims to ensure the longevity and safety of the aircraft by addressing the identified corrosion issues promptly. The requirement for compliance is tied to scheduled overhauls and specific flight cycle thresholds, ensuring that all affected aircraft receive the necessary attention to maintain their airworthiness.

Scope and Application

The Civil Aviation Regulations 1998, specifically Part 39 - 105 and the Schedule of Airworthiness Directives, applies to certain models of Saab SF340 series aeroplanes, namely the SF 340A with serial numbers from 340A-004 to 340A-159 and the 340B with serial numbers from 34B-160 to 34B-444. The regulation sets out mandatory service bulletins and actions to be taken to address identified issues with the main landing gear support assembly bearing housings. The scope of the directive includes all aircraft within the specified serial number ranges, requiring compliance with the SAAB Aircraft Mandatory Service Bulletin SAAB 340-57-036, which was issued in response to findings of corrosion in the bearing housings due to moisture ingress. Compliance with these directives is mandatory and depends on the aircraft's total flight cycles, with specific timelines provided for aircraft that have reached certain milestones in their operational life. The directive became effective on 31 December 1999, with amendments made to address the identified safety concerns and improve the non-destructive testing methods for inspection.

Key Provisions

The Civil Aviation Regulations 1998, specifically Part 39, Section 105, outlines a schedule of Airworthiness Directives for certain types of aircraft, including the Saab SF340 Series aeroplanes. One such directive, AD/SF340/69 Amendment 1, pertains to the maintenance and inspection of the main landing gear (MLG) support assembly bearing housings (Section 105.010). This directive applies to specific models and serial numbers of the Saab SF340 aircraft (Section 105.011). The directive requires actions in accordance with Saab Aircraft Mandatory Service Bulletin SAAB 340-57-036, which addresses issues related to corrosion in the bearing housings due to moisture ingress (Section 105.013). The directive imposes obligations on the operators and maintainers of the affected aircraft to ensure that inspections and actions are conducted as specified. For aircraft with a total of 32,000 or more flight cycles, the inspections must be completed within 4,000 flight cycles after 31 December 1999 (Section 105.014). For aircraft with between 24,000 and 32,000 total flight cycles, the inspections must be completed within 6,000 flight cycles after the same date (Section 105.015). Aircraft with fewer than 24,000 total flight cycles must comply with the inspections either at scheduled overhauls or within 6,000 flight cycles after 31 December 1999, whichever occurs later (Section 105.016). Compliance with these requirements is critical to ensure the safety and airworthiness of the aircraft. Failure to comply with the provisions of this Airworthiness Directive can result in serious safety issues, as the corrosion of the bearing housings can lead to fatigue cracks and a reduction in the fatigue life of the support assembly, potentially compromising the structural integrity of the aircraft. The Civil Aviation Safety Authority (CASA) has the authority to enforce these regulations, and breaches may result in civil penalties, enforcement actions, or even grounding of the aircraft until compliance is achieved. The exact penalties for non-compliance are detailed under the Civil Aviation Act 1988, where penalties can include fines and, in severe cases, imprisonment (Section 105.017). Ensuring adherence to these directives is therefore essential for the continued safe operation of the affected aircraft.