AD/SF340/7 Amdt 1 - Power Turbine Speed Signal - Overspeed Protection

Overview

The Civil Aviation Regulations 1998, administered by the Civil Aviation Safety Authority (CASA), are the primary piece of legislation governing civil aviation in Australia. This regulatory framework aims to ensure the safety and efficiency of the nation’s civil aviation sector, and includes detailed provisions for airworthiness directives, which are legally binding orders to correct an unsafe condition on an aircraft. One such directive, AD/SF340/7 Amendment 1, pertains to the Saab SF340 series aeroplanes and was enacted in 1987 to address the risk of uncontained engine failure due to power turbine overspeed. This directive mandates compliance with Saab Service Bulletin SF 340-76-018 and references the Swedish Airworthiness Directive SAD NO. 1-021, aiming to enhance safety by preventing overspeed conditions that could lead to catastrophic engine failure.

Scope and Application

The SAAB SF340 Series Aeroplanes Airworthiness Directive, specifically AD/SF340/7 Amendment 1, applies to SAAB 340A Aircraft and mandates compliance with SAAB Service Bulletin SF 340-76-018. This regulatory requirement ensures the implementation of the final closing action for overspeed protection, addressing the risk of engine power turbine overspeed and the potential for uncontained engine failure. The directive, which came into effect on 31 July 1987, is part of the broader framework established under the Civil Aviation Regulations 1998 and administered by the Civil Aviation Safety Authority (CASA). Its application is limited to the SAAB 340A series and does not extend to other aircraft types or models unless explicitly stated. The directive incorporates references to relevant international standards such as the Swedish Airworthiness Directive SAD NO. 1-021, ensuring a consistent approach to safety measures across different jurisdictions. Subordinate instruments may further refine or expand the directive's application, but the primary scope remains focused on enhancing the safety of SAAB 340A aircraft through specified modifications.

Key Provisions

The Civil Aviation Regulations 1998, specifically Part 39 - 105, under the Civil Aviation Safety Authority's (CASA) Schedule of Airworthiness Directives, includes a provision for Saab SF340 series aeroplanes, identified as AD/SF340/7 Amendment 1. This amendment, which pertains to the power turbine speed signal overspeed protection, applies to Saab 340A aircraft (s.1). The directive mandates that the action must be carried out in accordance with Saab Service Bulletin SF 340-76-018 (s.1). The directive notes that Swedish Airworthiness Directive SAD NO. 1-021 is relevant to this amendment (s.1). The directive became effective on 31 July 1987 (s.1). The background of this amendment explains that it was introduced to implement the final action required for overspeed protection to prevent engine power turbine overspeed and the associated risk of uncontained engine failure. This amendment supersedes the FAA Telegraphic AD T86-10-51 (s.1). The obligations imposed by this Airworthiness Directive require operators of Saab 340A aircraft to adhere to the specified action outlined in Saab Service Bulletin SF 340-76-018. This involves implementing the overspeed protection measure to ensure the power turbine does not exceed safe operational speeds, thus mitigating the risk of uncontained engine failure (s.1). Operators must ensure that the aircraft's power turbine speed signal system is functioning correctly and is compliant with the directive by the specified effective date, 31 July 1987. Failure to comply with this directive can result in the aircraft being considered non-airworthy, which would prevent it from operating until the required modifications are made (s.1). The Civil Aviation Regulations 1998 impose serious consequences for non-compliance with Airworthiness Directives such as AD/SF340/7 Amendment 1. Any breach of the directive can lead to enforcement actions by CASA. This may include fines, suspension, or revocation of the aircraft's certificate of airworthiness. Additionally, operators found to be in violation may face legal penalties under relevant aviation laws, which could include criminal charges for operating an aircraft in a non-airworthy condition (s.1). The exact penalties depend on the severity and intent behind the non-compliance but can include substantial financial penalties and imprisonment for serious breaches (s.1).