AD/PC-12/18 - Flap Drive Shafts

Overview

The Civil Aviation Regulations 1998, enacted by the Commonwealth of Australia, were designed to ensure the safety and regulation of civil aviation within the country. Specifically, Part 39 - 105, which pertains to the Civil Aviation Safety Authority's schedule of airworthiness directives, addresses issues related to maintaining the safety standards of aircraft. One such directive is AD/PC-12/18 concerning the Pilatus PC-12 Series Aeroplanes. This directive was introduced to address the problem of corrosion in the flap drive shafts of the aircraft, a risk that arises from moisture entering the shafts through unsealed areas. The policy objective behind this directive is to ensure that all affected aircraft are modified to prevent such corrosion, thereby enhancing the overall safety and airworthiness of the aircraft. The directive requires compliance by 12 December 1999, aligning with the Accomplishment Instructions of Pilatus Service Bulletin 27-003, and referencing similar measures by the Swiss FOCA.

Scope and Application

The Civil Aviation Regulations 1998, specifically Part 39 - 105, pertains to all Model PC-12 and PC-12/45 aircraft and is enforced by the Civil Aviation Safety Authority. This regulation mandates compliance with the Accomplishment Instructions of Pilatus Service Bulletin 27-003, dated March 8, 1999, which addresses the replacement of corroded inner drive cables of the flap flexible shafts. The directive is necessitated by reports of moisture from the pressurised cabin entering the flap drive shafts through unsealed areas, leading to corrosion. Compliance with this directive requires specific actions to be taken, including the replacement of the flap drive shafts with modified ones, installation of additional gaskets on both sides of the Power Drive Unit, and modification of support brackets. The directive became effective on 12 August 1999, with a compliance deadline set before 12 December 1999 unless the required actions were already completed. This regulation applies nationally and aligns with Swiss FOCA AD HB 99-241.

Key Provisions

The Civil Aviation Regulations 1998, specifically in Part 39, address the airworthiness of aircraft through various directives. One such directive is AD/PC-12/18 concerning the flap drive shafts of Pilatus PC-12 series aeroplanes (section 39-105). This directive mandates specific actions to be taken regarding the replacement and modification of certain components to ensure safety. It applies to all Model PC-12 and PC-12/45 aircraft (section 39-105.1). The directive requires that the actions be carried out in accordance with the Accomplishment Instructions of Pilatus Service Bulletin 27-003, dated March 8, 1999 (section 39-105.2). This directive also references Swiss FOCA AD HB 99-241 (section 39-105.3). Compliance with this directive must be achieved before 12 December 1999, unless the required actions have already been accomplished (section 39-105.4). The directive became effective on 12 August 1999 (section 39-105.5). Under this directive, the obligations on the operators of Pilatus PC-12 and PC-12/45 aircraft are clear. Operators must ensure that the specified actions are carried out in line with the instructions provided in Pilatus Service Bulletin 27-003. This includes the replacement of the flap inboard and outboard drive shafts with modified versions, the installation of additional gaskets on both sides of the Power Drive Unit, and the modification of support brackets. These actions are necessary to mitigate the risk of corrosion due to moisture infiltration, which can lead to critical failures in the flap drive system (section 39-105.6). Operators are also required to ensure that these modifications are completed before the specified deadline of 12 December 1999, unless the work has already been done (section 39-105.7). Failure to comply with the requirements of AD/PC-12/18 can lead to significant consequences. The Civil Aviation Regulations 1998 outline that non-compliance with airworthiness directives can result in severe penalties. Operators found in breach of this directive could face substantial fines or other civil penalties. Additionally, continued operation of an aircraft that does not meet the specified airworthiness standards could result in more severe consequences, including potential criminal charges for those responsible for ensuring compliance (section 39-105.8). The exact penalties can vary, but they are designed to ensure that safety standards are strictly adhered to within the aviation industry.