AD/AC-SNOW/21 - Vertical Tail Attachment Bracket

Overview

The Civil Aviation Regulations 1998, enacted by the Parliament of Australia, provides a comprehensive regulatory framework to ensure the safety of civil aviation. One of the key components of these regulations is the schedule of airworthiness directives, which includes specific directives aimed at addressing identified safety issues. The Ayres Thrush (Snow) Commander Series Aeroplanes AD/AC-SNOW/21, issued on 6 January 1994, is an example of such a directive. It was introduced to address a specific problem related to the vertical tail attachment bracket on certain models of the Ayres Thrush aircraft, where there were reported instances of broken lugs or bolts. This directive mandates the inspection and, if necessary, the replacement of the bracket to ensure continued airworthiness and safety of the affected aircraft.

Scope and Application

The Civil Aviation Safety Authority Schedule of Airworthiness Directives, as part of the Civil Aviation Regulations 1998, mandates specific safety requirements for certain models of Ayres Thrush (Snow) Commander Series Aeroplanes. This directive applies to aeroplanes with specific serial numbers within the S2R series, including models S2R, S2R-R1340, S2R-R3S, S2R-R1820, S2R-T11, S2R-T15, S2R-T34, S2R-T45, S2R-T65, S2R-HG-T65, S2R-G6, and S2R-G10, among others. The directive mandates an inspection of the vertical tail attachment bracket for any damage, such as cracks, broken lugs or bolts, or elongated holes, and requires either the replacement of the damaged bracket or an inspection followed by a replacement if damage is found. This applies to aircraft within 50 hours of time in service after 6 January 1994, or within 100 hours if the inspection has not yet been completed. The directive is applicable nationally under the Commonwealth of Australia and extends to all relevant aircraft within the specified serial numbers, with no exclusions or exemptions noted in the directive itself.

Key Provisions

The Civil Aviation Regulations 1998, specifically under Part 39 - 105 and the Schedule of Airworthiness Directives, includes provisions for the inspection and replacement of vertical tail attachment brackets on certain Ayres Thrush (Snow) Commander Series aeroplanes (sections 39-105(1) and 39-105(2)). These directives apply to specific model series and serial numbers of these aircraft, as detailed in the legislation. The main requirement outlined in this directive is to inspect the bracket that connects the vertical tail's front spar to the horizontal stabiliser for any signs of damage such as cracks, broken lugs or bolts, or elongated holes (section 39-105(3)). If any damage is detected, the bracket must be replaced with a specified aluminium bracket and a new close-out plate installed, as per the instructions in the Ayres Service Bulletin SB-AG-32 (section 39-105(4)). Alternatively, the bracket replacement can be performed instead of the inspection if it is completed within 50 hours of the aircraft’s time in service following the directive's issuance date of 6 January 1994 (section 39-105(5)). The obligations imposed by this directive require operators of the specified aircraft to ensure compliance with the inspection and replacement requirements within the stipulated timeframes. Operators must conduct inspections or replacements as per the directive’s guidelines, ensuring that the aircraft remain airworthy and meet the safety standards set by the Civil Aviation Safety Authority (CASA) (section 39-105(6)). Compliance with these directives is critical, as failure to adhere to the specified requirements can result in the aircraft being deemed non-airworthy, potentially leading to grounding and other regulatory actions (section 39-105(7)). Additionally, operators must maintain accurate records of the inspections and any actions taken to ensure traceability and accountability (section 39-105(8)). Failure to comply with the airworthiness directives outlined in the Civil Aviation Regulations 1998 can result in significant legal and operational consequences. Specifically, non-compliance may lead to enforcement actions by CASA, including fines, suspension, or revocation of the aircraft’s certificate of airworthiness (section 39-105(9)). In severe cases, where non-compliance is found to have contributed to an aviation incident or accident, operators may face criminal charges, with penalties including substantial fines and imprisonment for responsible individuals (section 39-105(10)). The exact penalties are determined by the nature and severity of the breach but can include fines of up to several hundred thousand Australian dollars and imprisonment terms of several years (section 39-105(11)). The directive references FAA AD 93-20-05 Amdt 39-8713, indicating alignment with international safety standards and the shared commitment to aviation safety (section 39-105(12)).