AD/BN-2/56 - Elevator Trim Cable

Overview

The Civil Aviation Regulations 1998, enacted by the Parliament of the Commonwealth of Australia, aim to ensure the safety and efficiency of civil aviation within Australia. One specific part of these regulations, Part 39 - 105, concerns the Civil Aviation Safety Authority's Schedule of Airworthiness Directives, which includes detailed requirements for maintaining the airworthiness of various aircraft. This particular legislative instrument, F2006B04767, addresses the critical issue of elevator trim cable wear in the Pilatus Britten-Norman BN-2 Series Aeroplanes, particularly those equipped with certain autopilot systems. The problem identified was the wear and fraying of the elevator trim cable splice, a safety concern that led to the issuance of this directive. The policy objective is to mandate specific maintenance actions to prevent potential failures in the elevator trim system, thereby ensuring the continued airworthiness and safety of the affected aircraft. This Airworthiness Directive mandates compliance with the procedures outlined in Pilatus Britten-Norman Mandatory Service Bulletin BN-2/SB 217 Issue 1, requiring actions to be taken within 50 hours of the directive's publication and at intervals not exceeding 100 hours thereafter. The directive references a similar action taken by the UK Civil Aviation Authority, ensuring that the safety measures are aligned with international standards. The directive is applicable to the BN2A and 2B Series Islander, and BN2T Turbine Islander aircraft, including those styled Defender, if they are fitted with the specified autopilot systems.

Scope and Application

The Civil Aviation Regulations 1998, specifically Part 39 - 105, pertains to the Airworthiness Directives issued by the Civil Aviation Safety Authority (CASA). One such directive, AD/BN-2/56, concerns the elevator trim cable for the Pilatus Britten-Norman BN-2 Series Aeroplanes, which includes the BN2A and 2B Series Islander, and BN2T Turbine Islander aircraft, including those styled Defender. This directive applies to aircraft equipped with either the Century 31 Autopilot System modified to NB/M/1271 or the Century 2000 Autopilot System modified to NB/M/1488. The directive requires compliance with Pilatus Britten-Norman Mandatory Service Bulletin BN-2/SB 217 Issue 1, referencing the UK Civil Aviation Authority AD 007-09-94. The directive mandates corrective action within 50 hours of time in service after 9 November 1994 and requires subsequent compliance at intervals not exceeding 100 hours of time in service. This directive is designed to address reported instances of wear and fraying of the elevator trim cable splice, which corresponds to specific wear areas at frame stations 352.4, 383.45, and 390.6, thereby ensuring the continued airworthiness of the affected aircraft.

Key Provisions

The Civil Aviation Regulations 1998, specifically Part 39 - 105, which concerns the Civil Aviation Safety Authority Schedule of Airworthiness Directives, includes a directive (AD/BN-2/56) relating to the elevator trim cable of the Pilatus Britten-Norman BN-2 Series Aeroplanes. This directive (section 1) applies to the BN2A and 2B Series Islander, and BN2T Turbine Islander aircraft, including those styled Defender, that are equipped with either the Century 31 Autopilot System (Modification NB/M/1271) or the Century 2000 Autopilot System (Modification NB/M/1488). The requirement outlined in the directive mandates that the action stipulated in the Pilatus Britten-Norman Mandatory Service Bulletin BN-2/SB 217 Issue 1 must be undertaken (section 2). It is noted that this directive corresponds with the UK CAA AD 007-09-94. Compliance with this directive is imperative within 50 hours of the aircraft's time in service following 9 November 1994, and must be repeated at intervals not exceeding 100 hours of time in service thereafter (section 3). The obligations imposed by this directive are clear and specific. Operators and owners of the affected aircraft must adhere to the requirements set out in the Pilatus Britten-Norman Mandatory Service Bulletin BN-2/SB 217 Issue 1. This includes ensuring that the elevator trim cable is inspected and maintained as per the service bulletin's instructions to prevent wear and fraying. The directive is explicit in its timing, mandating that the initial compliance action must be taken within 50 hours of the aircraft's time in service post the directive's issuance date, and that subsequent compliance actions must occur at intervals not exceeding 100 hours of time in service. This ongoing maintenance requirement underscores the importance of adhering to the specified schedule to maintain the aircraft's airworthiness. Failure to comply with this directive could result in serious consequences. The Civil Aviation Regulations 1998 establish that non-compliance with airworthiness directives can lead to civil or criminal penalties. While the specific penalties are not detailed in the directive itself, the general framework of the Civil Aviation Act 1988 and associated regulations could impose fines, imprisonment, or both. The severity of these penalties reflects the critical nature of adhering to airworthiness directives to ensure the safety and reliability of the aircraft in question. Operators and owners must, therefore, ensure strict adherence to the mandated schedule and procedures to avoid any legal ramifications.