AD/SWSA226/73 Amdt 1 - Current Limiter Protection

Overview

The Civil Aviation Regulations 1998, specifically Part 39 - 105, introduced the Civil Aviation Safety Authority's schedule of Airworthiness Directives (ADs) to ensure the safety of aircraft operations in Australia. This regulation was enacted to address the need for consistent and stringent safety standards in civil aviation. The ADs are formulated by the Civil Aviation Safety Authority (CASA) to provide specific instructions and requirements for maintaining the airworthiness of aircraft, thereby ensuring safety and compliance with aviation standards. The policy objective behind these regulations is to mitigate risks associated with aircraft operations by mandating specific actions to address identified safety issues, thus safeguarding the public and maintaining the integrity of the aviation industry. The Fairchild (Swearingen) SA226 and SA227 Series Aeroplanes AD/SWSA226/73 Amendment 1, focusing on current limiter protection, exemplifies the application of these regulations. This amendment was introduced to address the risk of current limiter failure in combination with engine failure, which could lead to a loss of power to the essential bus, potentially compromising flight safety. The regulation mandates the relocation of the current limiters in specified models and serial numbers of the aircraft to prevent such failures, ensuring continued compliance with safety standards within a defined timeframe. The amendment, effective from 30 June 1996, aligns with CASA's commitment to proactive safety management in civil aviation.

Scope and Application

The Civil Aviation Safety Authority's Schedule of Airworthiness Directives under the Civil Aviation Regulations 1998 applies to specific models of Fairchild (Swearingen) SA226 and SA227 series aeroplanes equipped with a direct current generator. The directive is applicable to aircraft with certain serial numbers, including SA226-T, SA226-AT, SA226-TC, SA226-T(B), SA227-AC, SA227-AT, SA227-BC, SA227-TT, SA227-CC, and SA227-DC models within designated ranges. The requirement outlined in the directive involves relocating the left and right hand essential bus current limiters in accordance with specified Fairchild Aircraft Service Bulletins. Compliance with this directive must be achieved within 2,000 hours of time in service after 9 November 1995, and the amendment was effective from 30 June 1996. This directive aims to mitigate the risk of current limiter failure in conjunction with an engine failure that could result in a loss of power to the essential bus.

Key Provisions

The Civil Aviation Regulations 1998, specifically Part 39 - 105, includes an airworthiness directive (AD) applicable to certain Fairchild (Swearingen) SA226 and SA227 series aeroplanes, as outlined in AD/SWSA226/73 Amendment 1. This directive mandates modifications to the current limiters for these aircraft to prevent potential failures that could lead to power loss to the essential bus (section 1). The directive applies to specific models and serial numbers of the SA226 and SA227 series aeroplanes that are equipped with a direct current generator (section 2). The primary requirement of this directive is the relocation of the left-hand (LH) and right-hand (RH) essential bus current limiters, as specified in certain Fairchild Aircraft Service Bulletins. Specifically, SA226-series aircraft must adhere to Service Bulletin 226-24-034, issued on 29 September 1994. Meanwhile, SA227-AC, SA227-AT, SA227-BC, and SA227-TTC models must comply with Service Bulletin 227-24-015 Rev 1, dated 23 February 1995. The SA227-CC and SA227-DC models are governed by Service Bulletin 7-24-002, also issued on 29 September 1994 (section 3). The directive references FAA AD 95-17-09R1 Amendment 39-9550 for additional guidance. Operators of the affected aircraft must ensure that the specified modifications are completed within 2,000 hours of time in service after 9 November 1995, the original effective date of the directive. This requirement remains unchanged, and the amendment came into effect on 30 June 1996. Non-compliance with this directive could result in significant safety risks, as the modifications are critical to preventing potential failures that could lead to loss of power to the essential bus (section 4). Failure to comply with the airworthiness directive could lead to various legal and safety consequences. The Civil Aviation Safety Authority (CASA) may impose penalties, and operators could face enforcement actions, including fines and potential grounding of the aircraft. Such non-compliance could also result in civil or criminal liability if it contributes to an aviation accident or incident. The severity of the penalties depends on the extent of the non-compliance and the resulting impact on aviation safety (section 5).