AD/DHC-6/60 Amdt 4 - Wing Front Spar Attachment Adaptors

Overview

The Civil Aviation Regulations 1998, as amended by the Legislative instrument F2006B09148, introduce specific airworthiness directives aimed at addressing the safety concerns associated with the DHC-6 series aeroplanes, particularly those fitted with aluminium wing to fuselage front adaptor fittings. This legislation was enacted to mitigate the risks posed by fatigue and stress corrosion cracks in these fittings, which have been a recurrent issue. The problem it addresses is the need to ensure that these aeroplanes meet safety standards by either replacing the problematic aluminium fittings with steel ones or by conducting regular inspections to detect any developing cracks. The policy objective behind this directive is to enhance the safety and reliability of DHC-6 series aeroplanes by implementing stringent measures that prevent the occurrence of structural failures. The Civil Aviation Safety Authority, as part of the Commonwealth of Australia, is the enacting body responsible for issuing these regulations to safeguard the aviation industry and the public.

Scope and Application

The Civil Aviation Regulations 1998, specifically Part 39 - 105, applies to all DHC-6 series aeroplanes that are fitted with aluminium wing to fuselage front adaptor fittings. This regulation is issued under the authority of the Civil Aviation Safety Authority and aims to address safety concerns associated with fatigue and stress corrosion cracks in these fittings. The geographic reach of this regulation is national, as it applies throughout the Commonwealth of Australia. The requirement is for the inspection and replacement of these fittings to ensure the continued airworthiness of the aircraft. Compliance with this regulation must be demonstrated by adhering to the intervals specified for inspections and by replacing the fittings with steel fittings before a specified deadline. The regulation references earlier directives and recommendations from Transport Canada, aligning with international safety standards. There are no stated exclusions or exemptions in the directive, and the application is extended through subordinate instruments, such as service bulletins, which provide detailed guidance on how to comply with the regulation.

Key Provisions

The Civil Aviation Regulations 1998, Part 39 – 105, specifically the Civil Aviation Safety Authority's Schedule of Airworthiness Directives for DHC-6 (Twin Otter) series aeroplanes, provides critical safety instructions under AD/DHC-6/60 Amendment 4. This directive is concerned with the wing front spar attachment adaptors of DHC-6 series aeroplanes fitted with aluminium wing to fuselage front adaptor fittings (AD/DHC-6/60 Amdt 4). The directive requires two primary actions: the inspection of the fittings as per de Havilland Service Bulletin No 6/476 Revision C, and the replacement of all aluminium fittings with steel fittings as outlined in de Havilland Service Bulletin No 6/500 Revision C. Once the replacement is completed, the need for inspections under the first requirement ceases. The regulations impose specific obligations on the parties and entities governed by this directive. Owners and operators of DHC-6 series aeroplanes must ensure that the inspections of the fittings are carried out in accordance with the specified service bulletin and at the required intervals. For fittings that have been reworked, inspections must occur at intervals not exceeding 250 hours of time in service. For all other aluminium fittings, inspections must be conducted at intervals not exceeding 500 hours of time in service. Furthermore, all aluminium fittings must be replaced with steel fittings before a specified deadline of 1 September 1995. Failure to comply with the requirements of this directive can result in significant civil or criminal consequences. The directive does not explicitly state penalties within its text, but non-compliance with Civil Aviation Regulations can generally lead to enforcement actions by the Civil Aviation Safety Authority. These actions can include fines, the grounding of non-compliant aircraft, and in severe cases, criminal prosecution. The exact penalties would depend on the specific nature and severity of the non-compliance, as well as any relevant provisions within the broader Civil Aviation Regulations 1998.