AD/PHZL/14 Amdt 4 - Blade and Hub - Shot Peening

Overview

The Civil Aviation Regulations 1998, administered by the Civil Aviation Safety Authority (CASA) under the Civil Aviation Act 1988, include specific Airworthiness Directives to ensure the safety of civil aviation. Part 39, Schedule 107 of these regulations mandates certain maintenance and inspection protocols for aircraft components, such as propellers, to prevent in-flight failures and ensure the continued airworthiness of aircraft. AD/PHZL/14 Amendment 4 addresses issues specifically related to Hartzell propellers, focusing on blade and hub maintenance to prevent blade separation and other failures. This amendment was introduced to address safety concerns raised by blade retention shoulder cracking and clamp screw failures, aiming to improve the structural integrity and operational safety of affected aircraft models. The policy objective is to maintain a high standard of aviation safety through proactive and regular inspection and maintenance requirements.

Scope and Application

The Civil Aviation Regulations 1998, specifically Part 39 - 107 Civil Aviation Safety Authority Schedule of Airworthiness Directives, applies to Hartzell propellers installed on various aircraft models including Aerostar, Air & Space America, Beech, Cessna, Found Brothers Aviation Ltd., Kwad Company, Mooney, Piper, Procaer, and Revo Inc., among others. The directive mandates action in accordance with specified procedures in Hartzell Service Bulletin 202, replacing previous requirements for shot peening with cold rolling, and addresses blade and hub maintenance to prevent cracking and blade separation. Compliance with these directives is mandatory for aircraft operators and maintenance providers operating within Australia, with a specific timeframe for inspections and actions based on the aircraft’s time in service. The regulation ensures that all covered aircraft meet specific safety standards for airworthiness, with adjustments made to the inspection intervals and methods as outlined in the directive.

Key Provisions

The Civil Aviation Regulations 1998, under PART 39 - 107, contain specific Airworthiness Directives concerning propellers, particularly the Hartzell variable pitch propellers. These directives pertain to specific models of propellers, including HC-92WK-() and HC-92ZK-() installed on a variety of aircraft models (sections (1)). The primary requirement is to follow Procedure #1 and Procedure #2 as outlined in Hartzell Service Bulletin 202 (section (1)). These procedures address blade and hub maintenance, specifically replacing the previous requirement for shot peening with a new requirement for compressive rolling, as introduced in Hartzell Service Bulletin 118 (section (2)). The obligations imposed by these regulations require operators to ensure compliance with the specified maintenance procedures. If the time since the last inspection under CAO 107 AD/PHZL/14 Amdt 3 is less than 450 hours, blade inspection and compressive rolling must be performed before the propeller reaches 500 hours of service or within 25 hours from the effective date of 20 July 1995, whichever comes later (section (2.a)). If the time since the last inspection exceeds 450 hours, the same inspection and rolling must occur before reaching 500 hours or within 25 hours from the effective date (section (2.b)). If there are no records of compliance, the inspection and rolling must occur within 10 hours from the effective date, followed by reinspections at intervals not exceeding 500 hours (section (2.c)). Failure to comply with these Airworthiness Directives may lead to serious safety concerns, given the reported incidents of blade separations due to cracking and failed clamp screws (section (Background)). While specific penalties are not detailed in the text, non-compliance with Civil Aviation Regulations can result in substantial penalties. Under the Civil Aviation Act 1988, violations may lead to civil penalties, including fines and potential criminal charges, depending on the severity of the breach and its impact on aviation safety. The maximum penalties can vary, but they are designed to enforce strict adherence to safety regulations to prevent accidents and ensure the safety of air travel.