AD/DHC-6/45 Amdt 1 - Fuselage Side Frames Stns 218.125 and 219.525

Overview

The Civil Aviation Regulations 1998, enacted by the Commonwealth of Australia, form a comprehensive set of rules governing civil aviation operations within the country. Part 39, specifically, deals with airworthiness directives that are critical in maintaining the safety standards of aircraft. Among these, AD/DHC-6/45 Amendment 1 addresses the issue of inter-rivet cracking on the fuselage side frames of DHC-6 (Twin Otter) series aeroplanes at specific stations. This directive was introduced to ensure the safety and airworthiness of these aircraft by mandating modifications to reduce the risk of cracking, thereby preventing potential in-flight failures. The policy objective is to align with international standards and ensure the safety of all personnel onboard by enforcing structural integrity checks and modifications as specified by the manufacturer's service bulletins. This legislation is a crucial step in mitigating risks associated with material stress and corrosion, ensuring that all applicable aircraft meet stringent safety benchmarks.

Scope and Application

The Civil Aviation Regulations 1998, specifically Part 39 - 105, pertains to the Civil Aviation Safety Authority’s Schedule of Airworthiness Directives, which is applicable to the DHC-6 (Twin Otter) series aeroplanes. This legislation mandates specific actions and modifications for aircraft with serial numbers ranging from 1 to 411 inclusive to ensure compliance with safety standards. The directive requires adherence to de Havilland Service Bulletins 6/371 and the incorporation of modifications 6/1461 or 6/1553 and 6/1462, aligning with Transport Canada’s AD CF-78-17 R1. Compliance with these requirements must be met at specified intervals until the modifications are implemented, and all actions must be completed prior to 1 January 1996. The amendment, effective from 2 April 1992, addresses the issue of inter-rivet cracking of the fuselage side frame skin flanges at Stations 218.125 and 219.525, which has been identified as a safety concern. The directive aims to mitigate this risk by ensuring that the aircraft’s structure is reinforced with improved material to resist stress corrosion.

Key Provisions

The Civil Aviation Regulations 1998, particularly in Part 39 - 105 under the Civil Aviation Safety Authority (CASA) Schedule of Airworthiness Directives, include provisions specific to the DHC-6 (Twin Otter) Series Aeroplanes (s1). The relevant Airworthiness Directive, AD/DHC-6/45 Amendment 1, addresses the issue of fuselage side frame skin flanges cracking at Stations 218.125 and 219.525 (s2). This directive applies to all DHC-6 Series aeroplanes with serial numbers ranging from 1 through 411 inclusive (s3). It mandates that operators take action in accordance with de Havilland Service Bulletin 6/371 and incorporate modifications 6/1461 or 6/1553, and 6/1462 to rectify the identified issues (s4). Operators and entities governed by these regulations must adhere to the specified actions and timelines set out in the Airworthiness Directive. Compliance involves performing actions as outlined in the requirement document, with inspections and modifications required at specified intervals until the aeroplanes are modified in accordance with the second requirement (s5). The directive also mandates that these modifications must be completed before 1 January 1996 (s6). Ensuring compliance means that operators must maintain detailed records of inspections, modifications, and any subsequent actions taken to address the identified structural issues. Failure to comply with the provisions of this Airworthiness Directive can result in significant consequences. Operators who do not adhere to the specified requirements and timelines risk facing civil penalties, which could include fines. The maximum penalties are determined according to the Civil Aviation Act 1988 and related regulations. Additionally, non-compliance could lead to the grounding of the affected aircraft, potentially disrupting operations and resulting in further financial and reputational damage. It is crucial for operators to meticulously follow the directive to avoid these potential penalties and ensure the continued airworthiness of their aircraft.