AD/PHZL/71 - Counterweight Clamp Bolts

Overview

The Civil Aviation Regulations 1998, enacted by the Australian Government, serve to maintain safety standards within the civil aviation sector. A specific instrument, F2006B06228, was introduced as an airworthiness directive to address safety concerns associated with Hartzell propellers, particularly Model HC-E4A-3(A,I) with certain serial numbers. This directive aims to mitigate risks by requiring the identification and replacement of defective propeller blade counterweight clamp bolts with improved bolts, as outlined in Hartzell Propeller Inc. Service Bulletin No. HC-SB-61-219, Revision 1, dated July 2, 1996. The directive mandates compliance within 45 days or 400 hours time in service after its effective date of 23 April 1998, ensuring that affected aircraft maintain safe operational standards. This proactive measure was introduced in response to an incident where a clamp bolt failure led to a significant in-flight separation and subsequent blade failure, underscoring the importance of stringent safety protocols in aviation.

Scope and Application

The Civil Aviation Regulations 1998, specifically Part 39 - 107, pertains to the Civil Aviation Safety Authority's schedule of airworthiness directives, with the current focus on propellers, namely Hartzell Model HC-E4A-3(A,I) propellers. These directives apply to all Hartzell Propeller Inc. Model HC-E4A-3(A,I) propellers with serial numbers HJ1 to HJ654, which are installed on aircraft such as the Raytheon Beech 1900D series. The directive requires that any defective propeller blade counterweight clamp bolts be identified and replaced with improved bolts as specified in Hartzell Propeller Inc. Service Bulletin No. HC-SB-61-219, Revision 1, dated July 2, 1996. Compliance with this airworthiness directive must be achieved within 45 days or 400 hours of time in service from the effective date of the directive, which is April 23, 1998. The directive was prompted by a separation of a counterweight clamp in flight, leading to a blade failure due to a defective socket head cap screw, as noted in the background.

Key Provisions

The key provisions of the Civil Aviation Regulations 1998, particularly AD/PHZL/71, are aimed at ensuring the airworthiness of certain propellers by addressing specific safety concerns. According to section 107, the directive applies to all Hartzell Propeller Inc. Model HC-E4A-3(A,I) propellers with serial numbers HJ1 to HJ654. This directive mandates that the defective propeller blade counterweight clamp bolts must be identified and replaced with improved bolts as per Hartzell Propeller Inc. Service Bulletin (SB) No. HC-SB-61-219, Revision 1, dated July 2, 1996. The directive also notes that these propellers are used on, but not limited to, Raytheon Beech 1900D series aircraft. The obligations under this directive are clear and must be met by all relevant parties. Aircraft operators, maintenance personnel, and other stakeholders must ensure compliance with the directive by replacing the defective bolts within 45 days or 400 hours time in service (TIS) after the directive's effective date of 23 April 1998, whichever occurs first. This compliance requirement is non-negotiable, as the directive underscores the importance of timely action to prevent potential in-flight failures that could lead to catastrophic consequences. Failure to comply with the provisions of AD/PHZL/71 could result in severe consequences. While the specific civil or criminal penalties are not detailed in the directive, non-compliance with airworthiness directives generally can lead to enforcement actions by the Civil Aviation Safety Authority (CASA). These actions can include fines, suspension or revocation of aircraft operating certificates, and other regulatory sanctions. The potential for significant financial and operational repercussions underscores the importance of adhering to the directive's requirements.