AD/DHC-6/40 - Wing Struts - Inspection and Modification

Overview

The Civil Aviation Regulations 1998, enacted by the Parliament of Australia, are a comprehensive set of rules and directives aimed at ensuring the safety and efficiency of civil aviation within the country. Among these, Part 39 - 105 of the Civil Aviation Regulations 1998 provides specific airworthiness directives to maintain the safety standards of various aircraft types, including the DHC-6 (Twin Otter) series aeroplanes. This particular legislation was introduced to address issues pertaining to the structural integrity of the wing struts in certain models of the DHC-6 series, thereby ensuring that these aircraft remain airworthy and safe for operation. The policy objective is to mandate regular inspections and modifications to these critical components to prevent potential failures that could compromise flight safety. The legislation mandates a stringent inspection and modification schedule for the wing struts of DHC-6 series aeroplanes with specific serial numbers, requiring an inspection within 120 hours of time in service and a modification within 360 hours of time in service after 31 May 1976. This directive aims to mitigate any risks associated with the identified structural concerns, ensuring that the aircraft meet the necessary safety standards set forth by the Civil Aviation Safety Authority. Compliance with these directives is essential for operators to maintain the airworthiness of their aircraft and ensure the safety of passengers and crew.

Scope and Application

The Civil Aviation Regulations 1998, specifically Part 39 - 105 Civil Aviation Safety Authority Schedule of Airworthiness Directives, applies to all DHC-6 (Twin Otter) Series Aeroplanes with serial numbers 1 to 462, 464, 465, 468, 469, 472, 473, 474, 478, and 481. This regulation mandates that these particular aircraft must undergo specific inspections and modifications concerning their wing struts. The directive issued under AD/DHC-6/40 is applicable within the Commonwealth of Australia and falls under the jurisdiction of the Civil Aviation Safety Authority (CASA). The scope of the regulation is geographically limited to Australian airspace and any Australian-registered aircraft within the specified serial number range. The regulation does not explicitly state any exclusions or exemptions, but it is understood that the requirements are mandatory for the specified aircraft. Compliance is achieved through adherence to the detailed instructions provided in De Havilland of Canada Service Bulletin No. 6/342, which outlines the necessary inspection and modification procedures. These procedures must be followed within specific timeframes: inspections are required within 120 hours of time in service after 31 May 1976, and modifications must be completed within 360 hours of time in service after the same date.

Key Provisions

The Civil Aviation Regulations 1998, particularly Part 39, Section 105, contain the Civil Aviation Safety Authority's (CASA) Schedule of Airworthiness Directives. This section mandates specific maintenance and modification procedures for DHC-6 (Twin Otter) series aeroplanes, specifically those with serial numbers (S/Nos.) 1 to 462, 464, 465, 468, 469, 472, 473, 474, 478, and 481. The directive (AD/DHC-6/40) issued pertains to the wing struts and requires both inspection and modification within certain timeframes. The directive mandates that inspections must be conducted within 120 hours of time in service after 31 May 1976. This means that operators of the specified DHC-6 Twin Otter aeroplanes must ensure that the wing struts are inspected to meet safety standards within this period. Following this inspection, the directive requires the wing struts to be modified within 360 hours of time in service after the same date. This modification is essential to ensure that the aircraft continues to meet airworthiness standards. The reference document for these procedures is De Havilland of Canada Service Bulletin No. 6/342. Operators and owners of the affected DHC-6 Twin Otter aeroplanes have specific obligations under this directive. They are required to ensure that the inspections and modifications are carried out in accordance with the specified timeframes and the instructions provided in the referenced service bulletin. Compliance with these requirements is mandatory to maintain the airworthiness of the aircraft. Failure to adhere to the stipulated inspection and modification schedules could result in the aircraft being deemed non-compliant and potentially grounded. Non-compliance with the airworthiness directive can result in severe consequences. The Civil Aviation Regulations 1998 outline that failure to inspect or modify the wing struts as required can be considered an offence. The penalties for such offences may include substantial fines, and in serious cases, criminal charges. The specific penalties are not detailed in the excerpt provided, but typically, such violations can lead to significant financial penalties and legal repercussions. Additionally, failure to comply with these directives can lead to civil consequences, such as the imposition of corrective actions by CASA, which might include the issuance of further directives or restrictions on the operation of the aircraft.