AD/PT6A/23 - Replacement of Compressor Delivery Heated Air Tube by a Non-Metallic Hose

Overview

The Civil Aviation Regulations 1998, enacted by the Australian Parliament, address various aspects of civil aviation safety, including the issuance of Airworthiness Directives (ADs) to ensure aircraft and engine safety. Specifically, AD/PT6A/23, issued under Part 39, targets the Pratt and Whitney Canada PT6A Series turbine engines, aiming to mitigate the risk of failures associated with the compressor delivery heated air tubes. The directive mandates the replacement of these tubes with non-metallic hoses to prevent potential failures identified in overseas incidents. The policy objective is to enhance aviation safety by addressing known vulnerabilities in the specified engine models, ensuring compliance with the directive within a specified timeframe to maintain airworthiness standards.

Scope and Application

The Civil Aviation Regulations 1998, specifically under Part 39 - 106, mandates the application of Airworthiness Directives (ADs) that govern the maintenance and safety of aircraft components, including Pratt and Whitney Canada's PT6A Series turbine engines. This particular AD, AD/PT6A/23, pertains to the replacement of the compressor delivery heated air tube with a non-metallic hose for certain PT6A-11AG and PT6A-15AG engines, identified by their respective serial numbers. The directive applies to these engines that fall within the specified serial number ranges, necessitating compliance to prevent potential failures observed in overseas incidents. Compliance with this directive must occur at the first opportunity, contingent on the availability of parts, but no later than the next High-Time Inspection (HSI) or the next overhaul, whichever comes sooner. The AD is underpinned by Pratt & Whitney Aircraft of Canada Ltd. Service Bulletin No. 12024 R1 or AD/UAC-T/38. This regulation extends to any entity or individual operating these specified engines within the jurisdiction of the Commonwealth of Australia, ensuring the safety and airworthiness of the aircraft in question.

Key Provisions

The Civil Aviation Regulations 1998, particularly Part 39, Section 106, include a schedule of airworthiness directives concerning Pratt and Whitney Canada's PT6A Series turbine engines (subsection (1)). Specifically, Airworthiness Directive (AD) PT6A/23 pertains to the replacement of the compressor delivery heated air tube with a non-metallic hose (subsection (2)). This directive applies to PT6A-11AG engines with serial numbers prior to PC-E10139 and PT6A-15AG engines with serial numbers prior to PC-E14012 (subsection (3)). Compliance with this directive is mandated at the first opportunity, subject to the availability of parts, but no later than the next High-Stress Inspection (HSI) or the next overhaul, whichever comes sooner (subsection (4)). The obligations imposed by AD/PT6A/23 require operators of the specified engines to ensure the replacement of the compressor delivery heated air tube with a non-metallic hose. This is to address the risk of failures identified in overseas incidents (subsection (5)). The directive mandates that the replacement must be carried out in a timely manner, as outlined, and documented appropriately. Acceptable documentation for compliance includes Pratt & Whitney Aircraft of Canada Ltd. Service Bulletin No. 12024 Revision 1 or AD/UAC-T/38 (subsection (6)). Failure to comply with AD/PT6A/23 could lead to significant safety risks, as the directive is issued to prevent further failures of the compressor delivery heated air tube (subsection (7)). The implications of non-compliance could include regulatory action, potential grounding of the aircraft, and safety risks to passengers and crew. The seriousness of these consequences underscores the importance of adhering to the directive’s requirements (subsection (8)).