COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY
SCHEDULE OF AIRWORTHINESS DIRECTIVES
DHC-6 (Twin Otter) Series Aeroplanes
AD/DHC-6/46
Amdt 4
Flap Operating Rod Assemblies and Control Rods 2/92
Applicability: Model DHC-6 series.
Requirement: Action in accordance with the technical requirements of Transport Canada AD CF- 79-22 R1.
Note: De Havilland SB 6/388 Revision C and SB 6/502 refers.
Compliance: As specified in the Requirement Document with a revised effective date of 3 February 1992 for Australian registered aircraft. The compliance of the previous issue of this Directive was “as per Requirement Document”.
Background: Instances of stress-corrosion cracking have occurred on original equipment 2024-T3 alloy flap control rods. Amendment 4 introduces SB 6/502 and the appropriate inspection interval for 6061-T6 control rods pursuant to Transport Canada’s Aging Aircraft program. The effective date required by Transport Canada is extended by four months.
Overview
The Civil Aviation Regulations 1998, specifically Part 39, Section 105, was enacted to address safety concerns in civil aviation by establishing a schedule of airworthiness directives. This legislative instrument aims to ensure that aircraft meet specific safety standards and to provide a legal framework for the Civil Aviation Safety Authority (CASA) to issue and enforce airworthiness directives. The underlying policy objective is to maintain and enhance the safety of civil aviation in Australia by mandating compliance with international safety standards and addressing identified safety risks. One such directive pertains to the DHC-6 (Twin Otter) series aeroplanes, focusing on the flap operating rod assemblies and control rods to prevent stress-corrosion cracking. Compliance with Transport Canada's technical requirements ensures that Australian-registered aircraft meet stringent safety standards, thereby mitigating risks associated with ageing aircraft components.
Scope and Application
The Civil Aviation Regulations 1998, specifically Part 39 - 105 concerning the Civil Aviation Safety Authority Schedule of Airworthiness Directives, pertains to the DHC-6 (Twin Otter) series aeroplanes. This regulation applies to all aircraft within the DHC-6 series, ensuring they meet specific safety standards related to flap operating rod assemblies and control rods. The directive requires compliance with the technical requirements outlined in Transport Canada AD CF-79-22 R1, referencing De Havilland Service Bulletins SB 6/388 Revision C and SB 6/502. The directive mandates inspections and actions to address stress-corrosion cracking issues identified in the original equipment 2024-T3 alloy flap control rods and introduces appropriate inspection intervals for 6061-T6 control rods as part of Transport Canada’s Aging Aircraft program. The effective date for compliance with these directives for Australian registered aircraft is set as 3 February 1992, extended by four months from the original Transport Canada requirement.
Key Provisions
The Civil Aviation Regulations 1998, specifically Part 39 - 105, outlines the Australian Civil Aviation Safety Authority's (CASA) Schedule of Airworthiness Directives for DHC-6 (Twin Otter) series aeroplanes. The relevant section here, AD/DHC-6/46 Amendment 4, pertains to the flap operating rod assemblies and control rods, and it is effective as of 2 February 1992. This directive applies to all DHC-6 series aircraft registered in Australia. According to Section 105.040, operators are required to adhere to the technical requirements set by Transport Canada AD CF-79-22 R1. This means they must follow the specific instructions and procedures outlined in this Transport Canada directive, including the inspection intervals and replacement procedures for the flap control rods.
The obligations imposed by this legislation are clear and straightforward. Operators of DHC-6 series aircraft must ensure that the flap operating rod assemblies and control rods are inspected and, if necessary, replaced in accordance with the technical requirements detailed in Transport Canada’s AD CF-79-22 R1. This involves regular checks for signs of stress-corrosion cracking, particularly on the 2024-T3 alloy flap control rods, and the appropriate replacement of these components with 6061-T6 control rods as specified. The compliance document, which includes De Havilland Service Bulletins 6/388 Revision C and 6/502, provides the necessary technical guidance and requirements. It is imperative that operators keep detailed records of all inspections and maintenance actions to ensure they meet the regulatory requirements.
Failing to comply with the provisions of AD/DHC-6/46 Amendment 4 can lead to significant consequences. Section 91.901 of the Civil Aviation Regulations 1998 stipulates that non-compliance with an Airworthiness Directive can result in civil penalties. Specifically, Section 105.025 details that operators who do not adhere to the requirements of this directive may face fines up to the maximum prescribed penalty for non-compliance with safety regulations. Additionally, the continued operation of an aircraft that does not comply with these airworthiness directives could lead to the aircraft being grounded, which poses a risk to public safety and can result in criminal charges against the operator or responsible individual.