AD/PHS/14 Amdt 2 - Titanium Nitrided Transfer Tube

Overview

The Civil Aviation Regulations 1998, specifically Part 39 - 107, was enacted to establish and maintain airworthiness standards in civil aviation, thereby ensuring the safety of aircraft operations. Among its various amendments, AD/PHS/14 Amendment 2, concerning "Titanium Nitrided Transfer Tube" for specific propeller models, was introduced to address safety concerns related to the engagement of propeller transfer tubes. This was necessitated by the discovery of wear issues in the quill of propellers, which could lead to disengagement from the transfer tube and subsequent safety risks. The objective of this amendment is to mitigate these risks by mandating the replacement of certain quills and ensuring compliance with specified requirements, thus enhancing the overall safety of the aircraft involved. The Civil Aviation Safety Authority, under the authority of the Civil Aviation Act 1988, established these regulations to ensure that all aviation operations within Australia adhere to stringent safety standards. This particular amendment was issued to correct and improve upon previous directives, ensuring that any quills mated with titanium nitrided transfer tubes, or those without clear records of their mating history, are replaced to prevent potential safety hazards. The policy objective is to maintain the highest standards of airworthiness and to protect the public by reducing the risk of in-flight failures related to propeller mechanisms.

Scope and Application

The Civil Aviation Regulations 1998, as part of the Australian Civil Aviation Safety Authority's (CASA) regulatory framework, specifically address the airworthiness of aircraft components through Airworthiness Directives (ADs). One such directive, AD/PHS/14 Amendment 2, concerns the replacement of propeller transfer tubes in certain propeller models to mitigate safety risks identified in earlier investigations. This directive applies to specific propeller models, including all model 14RF-9, -19, and -21, as well as 14SF-5, -7, -11, -15, -17, -19, and -23 propellers, and the Hamilton Standard-British Aerospace Model 6/5500/F-1 propeller. These propellers may be installed on various aircraft types, including the EMB-120 Series, SAAB-340B, ATR42-100, -300, -320, ATR72-101, -201, DHC-8-100, -300, -314, CASA CN-235, -235-100, Canadair CL215T, and BAe ATP aircraft. The requirement mandates that PCU ballscrew quills either previously mated with a titanium nitrided transfer tube or lacking documentation showing the type of transfer tube must be replaced with a new quill or one that has never been paired with a titanium nitrided transfer tube. Compliance with this directive is necessary to ensure the continued safety of the aircraft operations and adhere to the updated technical requirements as specified in the requirement document, effective from 9 August 1993.

Key Provisions

The Civil Aviation Regulations 1998, specifically Part 39 - 107, mandates compliance with airworthiness directives as outlined in the Civil Aviation Safety Authority's (CASA) Schedule. One such directive, AD/PHS/14 Amendment 2, pertains to the titanium nitrided transfer tube in variable pitch propellers, particularly those made by Hamilton Standard (section 10/93 DM). This directive applies to specific propeller models, including 14RF-9, -19, -21, and 14SF-5, -7, -11, -15, -17, -19, and -23, as well as the Hamilton Standard-British Aerospace Model 6/5500/F-1. These propellers are commonly installed on various aircraft types such as the EMB-120 Series, SAAB-340B, ATR42-100, -300, -320, ATR72-101, -201, DHC-8-100, -300, -314, CASA CN-235, -235-100, Canadair CL215T, and BAe ATP (section Applicability). Compliance with this directive involves ensuring that the propeller transfer tubes meet the specified requirements unless a previous action in accordance with FAA AD 93-06-06 Amendment 39-8531, which supersedes FAA AD T91-11-51, has been carried out (section Requirement). Specifically, if the propeller has either been paired with a titanium nitrided transfer tube or lacks documentation showing which type of transfer tube it was paired with, the PCU ballscrew quill must be replaced. This applies to certain propeller models such as the 14RF-21, 14RF-9, 14RF-19, 14SF series, and the Hamilton Standard-British Aerospace 6/5500/F-1. The compliance must adhere to the requirement document, which was revised and took effect on 9 August 1993 (section Compliance). The directive arose from an investigation that revealed issues with propeller quills wearing out and failing to engage with the transfer tube. To address this, the directive reduces the allowable wear in the quill, mandates more frequent inspections, and provides detailed termination actions. Failure to comply with the AD/PHS/14 Amendment 2 could result in serious safety issues, potentially leading to propeller failure during flight. The regulations impose a clear obligation on aircraft operators and maintenance personnel to ensure that the specified components are either replaced or inspected according to the outlined procedures to maintain the airworthiness of the aircraft. In terms of penalties, failure to comply with the airworthiness directives set out in the Civil Aviation Regulations 1998 can lead to both civil and criminal consequences. Civil penalties may include fines and other financial penalties, while criminal penalties can include imprisonment, depending on the severity of the non-compliance. The specific penalties for breaches of the airworthiness directives are determined by the Civil Aviation Safety Authority and can vary based on the nature and extent of the violation. Ensuring compliance with these directives is crucial to maintaining the safety standards required in civil aviation.