AD/DHC-6/19 - Propeller and Power Control Lever Interlock - Mod

Overview

The Civil Aviation Regulations 1998, administered by the Civil Aviation Safety Authority (CASA) and overseen by the Australian Parliament, were enacted to ensure the safety and efficiency of civil aviation within Australia. One aspect of this legislation involves the implementation of Airworthiness Directives (ADs) to maintain the airworthiness of aircraft. Specifically, AD/DHC-6/19 focuses on the DHC-6 (Twin Otter) series aeroplanes, addressing the issue of propeller and power control lever interlock. This directive was introduced to mitigate the risk of accidental propeller deployment by ensuring that the propeller and power control lever are properly interlocked. The objective of this specific AD is to enhance flight safety by mandating compliance within 100 hours of time in service after the directive's issuance date of 23 December 1969, with certain serial numbers excluded from the requirement.

Scope and Application

The Civil Aviation Regulations 1998, specifically Part 39 - 105, pertains to airworthiness directives, with a particular focus on the De Havilland Canada DHC-6 (Twin Otter) Series Aeroplanes. This legislation applies to all models of DHC-6 Twin Otter aeroplanes with serial numbers (S/Nos.) ranging from 2 to 213, excluding the aeroplanes with serial numbers 30, 58, 96, 148, 206, 208, 210, and 212. The regulation mandates compliance with the modifications outlined in De Havilland of Canada Service Bulletin No. 6/183, Revision B, specifically regarding the propeller and power control lever interlock, within 100 hours of time in service after 23 December 1969. The Civil Aviation Regulations 1998 are applicable across the Commonwealth of Australia and are enforced by the Civil Aviation Safety Authority (CASA). This particular directive ensures that the specified aircraft models meet safety standards by adhering to the prescribed modifications, thereby maintaining the safety and airworthiness of these aircraft within the Australian aviation industry.

Key Provisions

The Civil Aviation Regulations 1998, specifically under PART 39 - 105, detail the requirements and obligations for the airworthiness of DHC-6 (Twin Otter) series aeroplanes. Section AD/DHC-6/19 addresses the modification of the propeller and power control lever interlock, as stipulated in Mod10/69. This directive applies to all models of the Twin Otter series with specific serial numbers (2 to 213), excluding the aircraft with serial numbers 30, 58, 96, 148, 206, 208, 210, and 212. Compliance with this airworthiness directive is mandated within 100 hours of time in service after 23 December 1969, as outlined in De Havilland of Canada SB No. 6/183, Rev. B. The obligations imposed by this regulation require that the affected aircraft undergo a specific modification to the propeller and power control lever interlock. This modification is essential to ensure the safety and reliability of the aircraft's operation. Operators and owners of the affected Twin Otter aircraft must ensure that these modifications are completed by qualified personnel in accordance with the specifications provided in the referenced document. The requirement is clear and unambiguous, mandating that the specified modifications be carried out within the stipulated timeframe to maintain compliance with airworthiness standards. Failure to comply with the airworthiness directive AD/DHC-6/19 can lead to significant consequences. Firstly, the aircraft will not be considered airworthy, which can result in grounding until the necessary modifications are completed. This non-compliance can have serious implications for the operator, including potential safety risks and legal repercussions. Additionally, operators who fail to meet the compliance deadlines may face penalties under the Civil Aviation Act 1988. These penalties can include fines and other enforcement actions, with the severity depending on the extent of the non-compliance and any resulting safety issues. In terms of penalties, the Civil Aviation Regulations 1998 provide for a range of enforcement actions for breaches of airworthiness directives. The maximum penalties can include substantial fines, which may be significant given the importance of compliance for aviation safety. Furthermore, persistent or severe non-compliance can lead to more serious legal consequences, including potential criminal charges if the breach results in safety incidents. It is crucial for operators and owners to adhere strictly to these directives to avoid any legal or safety-related issues.