AD/AC/88 Amdt 1 - Flap System

Overview

The Civil Aviation Regulations 1998, as amended by the Legislative instrument F2006B02149, address a specific safety concern related to the flap systems of certain Twin Commander series aeroplanes. Enacted by the Civil Aviation Safety Authority, this regulation aims to mitigate the risk of flap system failures by mandating regular inspections and maintenance of the flap system components. This legislative instrument responds to reports of cable fatigue and frayed wires, particularly affecting the master pulley cable, which could lead to a loss of control of the aircraft. The regulation requires inspections and corrective actions to be performed within a specified timeframe, ensuring the continued airworthiness and safety of the aircraft in question.

Scope and Application

The Civil Aviation Regulations 1998, specifically Part 39 - 105, which pertains to the Civil Aviation Safety Authority's Schedule of Airworthiness Directives, applies to certain Twin Commander (Gulfstream/Rockwell/Aerocommander 500, 600, and 720) series aeroplanes. These include models 500, 500A, 500B, 500S, 500U, 520, 560, 560A, 560E, 560F, 680, 680E, 680F, 680FL, 680FL(P), 680FP, 680T, 680V, 680W, 681, 685, 690, 690A, 690B, 690C, 690D, 695, 695A, 695B, and 720. The regulation is applicable to these aircraft regardless of their registration or location of operation within Australia, thus extending its reach across the entire Commonwealth. The directive mandates inspections and actions concerning the flap system to prevent potential failures that could lead to loss of control, as reported by the FAA. Compliance is required within 300 hours’ time in service after the directive's effective date of 16 July 1998. The regulation references specific service bulletins and amendments for achieving the required compliance, ensuring that any discrepancies identified during inspections are addressed appropriately.

Key Provisions

The Civil Aviation Regulations 1998, specifically Part 39 – 105, under the Civil Aviation Safety Authority Schedule of Airworthiness Directives, addresses the flap system requirements for Twin Commander (Gulfstream/Rockwell/Aerocommander 500, 600, and 720) series aeroplanes. This regulation applies to a broad range of models within this series, as detailed in the applicability section (Section 1). The directive mandates specific inspections and, if necessary, rework or replacement of parts to ensure the continued airworthiness and safety of these aircraft (Section 2). The main operative sections of this directive require inspections of the flap system cable grooves, pulleys, and cable assemblies. Owners or operators of the affected aircraft must ensure that these inspections are performed in accordance with the instructions provided in Twin Commander Aircraft Corporation Mandatory Service Bulletin (SB) 226 or SB 226 Revision 1 (Section 2(a)-(d)). These inspections include checking the width of cable grooves, looking for signs of pulley rubbing on support brackets, and identifying any frayed wires in the pulley cable assemblies. If any discrepancies are found, the affected parts must be reworked or replaced as detailed in the service bulletin (Section 2(d)). Additionally, pulleys that meet the specified criteria must be marked with two parallel lines, as instructed in the bulletin (Section 2(d), Note 1). The obligations imposed by this directive are clear: owners or operators must ensure that the specified inspections and necessary actions are carried out within 300 hours of time in service after 16 July 1998, unless these actions have already been completed (Section 3). The directive stipulates that this amendment becomes effective on 16 July 1998, meaning that compliance must be achieved by this date (Section 4). Failure to adhere to these requirements may result in serious safety implications, as the directive is in response to reports of cable fatigue and frayed flap system cables that could lead to a flap system failure and subsequent loss of control (Section 5). Breaching the provisions of this airworthiness directive can lead to severe consequences. The regulations do not explicitly state penalties, but non-compliance can result in the aircraft being deemed unairworthy, which could lead to enforcement actions by the Civil Aviation Safety Authority. These actions might include grounding the aircraft, fines, or other regulatory sanctions. Furthermore, failure to comply with these safety directives could potentially result in civil or criminal liability in the event of an accident or incident caused by the non-compliance (Section 5, Note 2).