AD/CL-600/20 - ADG Output Harness Chafing

Overview

The Civil Aviation Safety Authority (CASA) introduced the Civil Aviation Regulations 1998, specifically Part 39 - 105, to enhance aviation safety through the enforcement of airworthiness directives. This legislation aims to address identified safety issues and ensure the safe operation of aircraft. One such directive is AD/CL-600/20, which pertains to Bombardier (Canadair) CL-600 (Challenger) series aeroplanes, focusing on the prevention of ADG output harness chafing. This directive was enacted following reports of three instances where the ADG electrical output harness was chafed while in the stowed position, leading to short circuits, loss of electrical power to the essential bus, and damage to the harness and its supporting structure. The policy objective behind this directive is to mandate timely corrective actions to mitigate these risks, ensuring the continued airworthiness and safety of the affected aircraft.

Scope and Application

The Civil Aviation Regulations 1998, as amended, apply to all Bombardier (Canadair) CL-600 series aeroplanes and are enforced by the Civil Aviation Safety Authority (CASA) under Part 39 - 105 of the schedule of airworthiness directives. This particular airworthiness directive, AD/CL-600/20, mandates specific maintenance actions to address the issue of the auxiliary power unit (APU) output harness chafing, which has led to reported incidents of short circuits and subsequent damage. The directive is applicable to all CL-600 aircraft as specified in the requirement documents, and it is imperative for operators to comply with the specified timelines to ensure the continued airworthiness of the aircraft. Non-compliance with the requirements may result in the aircraft being grounded or denied operations until the issues are rectified. The directive does not specify any exclusions or exemptions and applies across the Commonwealth of Australia, as CASA is the regulatory authority with jurisdiction over civil aviation safety in the country. The directive may be further extended or modified through subordinate instruments issued by CASA.

Key Provisions

The Civil Aviation Regulations 1998, under Part 39 - 105, mandate specific airworthiness directives for certain aircraft models. In particular, the AD/CL-600/20 directive (section 1) addresses a critical issue with the Bombardier (Canadair) CL-600 (Challenger) Series aeroplanes, namely the chafing of the ADG (Auxiliary Power Unit) output harness when it is stowed. The directive requires two key actions: first, the implementation of Part A of Canadair Service Bulletin A600-0612 or A601-0370 as applicable (section 2(1)); and second, the implementation of Part B of the same service bulletins (section 2(2)). Compliance with these requirements must be achieved within specified timeframes: Requirement 1 must be completed within 25 hours of time in service after 13 June 1991, while Requirement 2 must be completed within 600 hours of time in service after the same date (section 3). The obligations under this directive are clear and specific. Operators of the CL-600 aircraft must ensure that the actions outlined in the Canadair Service Bulletins are thoroughly carried out to prevent the chafing of the ADG output harness. This involves inspecting, repairing, or replacing the harness as necessary, and ensuring that any related structural damage is also addressed. The directive stipulates that these actions must be taken within the defined timeframes to maintain the airworthiness of the aircraft and prevent potential safety hazards (section 3). Operators are expected to maintain accurate records of compliance to demonstrate adherence to the regulatory requirements. Failure to comply with the airworthiness directives can result in significant legal and safety consequences. Under the Civil Aviation Regulations 1998, non-compliance may lead to enforcement actions by the Civil Aviation Safety Authority (CASA). Such actions can include fines, the grounding of non-compliant aircraft, and potential criminal charges for serious breaches. The severity of the penalties can depend on the nature and extent of the non-compliance, but the regulations provide for substantial fines and imprisonment for those found in breach of the safety directives (section 4). Ensuring adherence to these directives is therefore critical for maintaining both operational safety and regulatory compliance.