Overview

The Civil Aviation Regulations 1998, particularly in PART 39 - 105, introduced an Airworthiness Directive (AD) to address safety issues with the Bombardier (Boeing Canada/De Havilland) DHC-8 Series Aeroplanes. This AD, specifically AD/DHC-8/81, was enacted to rectify a condition identified in certain DHC-8 series 100, 200, and 300 aircraft, where the absence of a back up pressure regulating valve could lead to excessive pressure build-up, resulting in critical failures such as pump body fractures, loss of engine oil, and inability to feather the propeller. The directive was issued by the Civil Aviation Safety Authority (CASA) under subregulation 39.1 (1) of the CAR 1998, with the objective of ensuring the continued airworthiness of the affected aircraft by mandating the incorporation of the back up pressure regulating valve in accordance with Bombardier Service Bulletin 8-61-31. The directive became effective on 6 September 2001, with compliance required at the next scheduled engine shop visit after this date but no later than 12 March 2003.

Scope and Application

This Airworthiness Directive issued under the Civil Aviation Regulations 1998 applies to specific models of Bombardier (Boeing Canada/De Havilland) DHC-8 series aeroplanes with serial numbers ranging from 003 to 554, which do not already incorporate a back up pressure regulating valve as per Bombardier Service Bulletin 8-61-31. The requirement outlined in the directive mandates the incorporation of this back up pressure regulating valve between the engine reduction gearbox and the auxiliary feather pump on both engines, in accordance with the specified service bulletin. The directive aims to address incidents where failure of the oil pressure regulating valve in the PCU oil pump has led to excessive pressure build up, resulting in pump body fracture, loss of engine oil, and an inability to feather the propeller. The directive becomes effective on 6 September 2001, and the required action must be taken at the next scheduled engine shop visit after this date but no later than 12 March 2003. This AD was issued by the Civil Aviation Safety Authority and is notified in the Commonwealth of Australia Gazette on 15 August 2001.

Key Provisions

The Civil Aviation Regulations 1998, particularly Part 39 - 105, detail the requirements and obligations for maintaining aircraft airworthiness. Specifically, Airworthiness Directive (AD) AD/DHC-8/81 mandates specific actions to rectify an identified unsafe condition on Bombardier (Boeing Canada/De Havilland) DHC-8 Series Aeroplanes, serial numbers 003 to 554, which do not incorporate a backup pressure regulating valve (section 39.1(1)). This AD aims to address incidents where failure of the oil pressure regulating valve has led to excessive pressure build-up, pump body fractures, engine oil loss, and propeller feathering issues. The primary requirement (section 1) is the incorporation of a backup pressure regulating valve between the engine reduction gearbox and the auxiliary feather pump on both engines, following Bombardier Service Bulletin 8-61-31. This directive is necessary to ensure continued safe operation of the specified aircraft models. Compliance must be achieved at the next scheduled engine shop visit following the AD's effective date but no later than 12 March 2003 (section 2). This directive became effective on 6 September 2001, underscoring the urgency and necessity of adhering to the specified timeframes and instructions. Entities governed by this AD, such as aircraft operators and maintenance service providers, must ensure that the required modifications are completed within the stipulated timeframe. Failure to comply with this AD may result in serious safety risks, including potential engine failure and loss of propeller feathering capability, which could compromise flight safety. Operators must document compliance and maintain records of the modifications made to satisfy the AD's requirements. Non-compliance with this Airworthiness Directive can lead to significant legal and safety consequences. Specifically, the AD imposes civil penalties, including fines, for operators who fail to adhere to the mandated modifications. The maximum penalty for non-compliance can be substantial, reflecting the critical nature of the safety improvements required by the AD. Additionally, the Civil Aviation Safety Authority (CASA) has the authority to ground non-compliant aircraft, which can disrupt operations and potentially result in further financial and reputational damage to the operators.