AD/DHC-6/36 Amdt 2 - Overhead Console Control Quadrants

Overview

The Civil Aviation Regulations 1998, amended in 2006, were enacted to regulate civil aviation and ensure safety standards are met across Australia. Part 39 of these regulations, specifically pertaining to Airworthiness Directives for the DHC-6 (Twin Otter) Series Aeroplanes, was introduced to address the identified problem of cracking and fracture in the control cable quadrants of the overhead console. This legislation is overseen by the Civil Aviation Safety Authority (CASA) and was designed to ensure the ongoing airworthiness and safety of DHC-6 aircraft by mandating specific maintenance actions. The primary policy objective of this directive is to prevent the recurrence of structural failures in the control quadrants through regular inspections and necessary modifications, thereby enhancing the overall safety of civil aviation operations.

Scope and Application

The Civil Aviation Safety Authority Schedule of Airworthiness Directives pertains specifically to the DHC-6 (Twin Otter) series aeroplanes and is set out under the Civil Aviation Regulations 1998, Part 39 - 105. This legislation mandates specific inspections and modifications to the overhead console control quadrants in order to ensure the airworthiness and safety of these aircraft. The requirements outlined necessitate inspections according to de Havilland Service Bulletin 6/519 and the incorporation of de Havilland Modification 6/1895 if cracks are detected. This directive applies to all DHC-6 series aircraft operating under the Commonwealth of Australia and must be adhered to by operators of these aircraft. The scope of this legislation is geographically confined to the national jurisdiction of Australia, ensuring that all aircraft within its airspace comply with these safety standards. There are no exclusions or exemptions mentioned within the text, implying that all DHC-6 series aircraft must comply with these directives. The enforcement of this Act may be extended or detailed further through subordinate instruments, ensuring that the safety standards remain stringent and up-to-date with technological advancements and safety findings.

Key Provisions

The Civil Aviation Regulations 1998, specifically Part 39 - 105, detail the requirements for the airworthiness of DHC-6 (Twin Otter) series aeroplanes, as set out in Amendment 2 (AD/DHC-6/36). The primary requirement under this amendment (Section 1) is the inspection and potential modification of the control quadrant assembly of the overhead console. The inspection must be conducted in accordance with Part A of Accomplishment Instructions of de Havilland Service Bulletin 6/519. If no cracks are detected based on the criteria outlined in Part A of Service Bulletin 6/519, the aircraft must undergo periodic inspections as detailed in the de Havilland Inspection Requirements Manual PSM 1-6-7, Chapter 76, until Modification 6/1895 is incorporated. If cracks are detected in the control quadrant assembly as per the criteria in Part A, paragraph 4 of Service Bulletin 6/519, the aircraft must incorporate de Havilland Modification 6/1895. If the cracks are identified under the criteria in Part A, paragraph 5 of Service Bulletin 6/519, the modification must be completed within 200 flight hours. Additionally, an inspection for crack propagation must be conducted at 100 flight hours after the last inspection to ensure that the magnitude and location of any cracks remain within specified limits. The incorporation of de Havilland Modification 6/1895 is considered the terminating action for this airworthiness directive. The obligations under the Civil Aviation Regulations (Section 2) require that compliance with the above provisions be achieved within 100 hours of the aircraft being in service after 2 March 1995, and in any case, prior to 1 January 1997. The regulation aims to address the known issue of cracking and fracture of the control cable quadrants (P/N C6CE 1010-27 and -29) in the overhead control console by mandating specific modifications and inspections. This directive is a response to in-service cracking of the previously modified quadrants, necessitating further inspections until the improved modification is fully incorporated. The Civil Aviation Regulations 1998 impose penalties and consequences for non-compliance with the specified airworthiness directives. While the exact penalties are not detailed in the provided text, it is understood that breaches of these regulations can result in civil or criminal liabilities, including fines and other sanctions. The severity of these penalties can vary depending on the nature and extent of the non-compliance, but they serve to enforce the importance of adhering to the prescribed airworthiness standards to ensure the safety of aircraft operations.