AD/DHC-6/65 - Wing Strut Chafing

Overview

The Civil Aviation Regulations 1998, administered by the Civil Aviation Safety Authority (CASA), provide a comprehensive framework for ensuring the safety of aviation operations in Australia. Part 39, which includes Airworthiness Directives (ADs), is particularly crucial in maintaining the airworthiness of aircraft. One such AD, AD/DHC-6/65, was introduced on 2 April 1992 to address a specific safety concern identified in the DHC-6 (Twin Otter) Series Aeroplanes. This directive was a response to an issue highlighted by Transport Canada's review of aging aircraft, mandating inspections and modifications to prevent potential chafing of the wing struts. The policy objective of this AD was to ensure that the protective nylon shield was installed, and if not, to require a thorough inspection and subsequent modification to mitigate the risk of damage to the wing struts. The AD/DHC-6/65 emphasises timely compliance, stipulating an inspection within 25 hours of service after the directive's issuance and mandating modifications before 25 June 1992. This directive was enacted by the Australian Government to align with international safety standards and to safeguard the operational integrity of the DHC-6 Twin Otter aircraft in Australia, reflecting a commitment to maintaining high safety benchmarks in the national aviation sector.

Scope and Application

The Civil Aviation Regulations 1998, under Part 39 - 105, pertains specifically to the airworthiness directives issued by the Civil Aviation Safety Authority (CASA). This particular legislative instrument, AD/DHC-6/65, concerns the DHC-6 (Twin Otter) series aeroplanes and mandates the inspection and modification of wing struts to prevent chafing. The directive applies universally to all models within this series, ensuring that operators and owners of these aircraft must adhere to the specified requirements. The directive’s compliance timeline requires an inspection within 25 hours of service following 2 April 1992, and the necessary modifications must be completed before 25 June 1992. The legislation is enforceable within the Commonwealth of Australia, overseen by CASA, which is responsible for enforcing aviation safety standards. No exclusions or exemptions are specified in this directive, meaning all DHC-6 (Twin Otter) aeroplanes must comply with the outlined requirements.

Key Provisions

The Civil Aviation Regulations 1998, specifically Part 39 - 105, includes a detailed schedule of airworthiness directives for various aircraft types, such as the DHC-6 (Twin Otter) Series Aeroplanes. One such directive, AD/DHC-6/65, addresses wing strut chafing. According to section 4/92, this directive applies to all models of the DHC-6 series. It mandates that operators inspect the aircraft for the presence of a protective nylon shield in the wing strut upper fairings, which was incorporated by de Havilland Modification 6/1581. If the protective shield is absent, operators must visually inspect the struts for any damage as outlined in de Havilland Service Bulletin 6/342, and then implement Modification 6/1581. This directive references Transport Canada’s Airworthiness Directive CF-91-30 dated 8 August 1991. Operators of DHC-6 series aeroplanes are required to comply with the inspection and modification schedule stipulated in the directive. According to the regulation, the inspection must occur within 25 hours of time in service after 2 April 1992. Following the inspection, any necessary modifications must be completed before 25 June 1992. This directive was identified as mandatory action during Transport Canada's review of aging aircraft, underscoring the importance of maintaining structural integrity to ensure flight safety. Failure to comply with the provisions of this directive could result in significant legal and safety consequences. Under the Civil Aviation Act 1988, non-compliance with airworthiness directives can be considered a breach of regulations. The Civil Aviation Safety Authority (CASA) may impose penalties, which can include fines and other sanctions. The severity of the penalties can vary depending on the nature and extent of the non-compliance, but they may also include potential grounding of the aircraft until the required modifications are made. Ensuring adherence to these directives is therefore crucial for the safety and legality of operating DHC-6 series aeroplanes in Australia.