Overview

The Civil Aviation Safety Authority (CASA) introduced the Airworthiness Directive (AD) AD/PHZL/80 to address the problem of cracks in Hartzell Propeller Inc. model HC-A6A-3 series propellers with A10460 series composite blades, which could lead to in-flight separation and resultant damage or loss of control of the aircraft. This AD was enacted under subregulation 39.1 (1) of the Civil Aviation Safety Regulations 1998. The policy objective of the directive is to enhance aviation safety by ensuring that these specific propellers are regularly inspected and maintained to prevent unsafe conditions that could compromise flight safety. The directive became effective on 25 December 2003, with inspections required within 100 propeller flight hours or 30 days from the effective date, followed by inspections at intervals not exceeding 300 propeller flight hours, and at each overhaul of the propeller.

Scope and Application

This Airworthiness Directive (AD) applies to Hartzell Propeller Inc. model HC-A6A-3 series propellers with A10460 series composite blades, installed on Short Brothers Ltd. SD3-60 Series airplanes and potentially other aircraft. The directive mandates specific inspections and actions to address the issue of composite blade cracking, which has led to in-flight separations and potential damage to the aircraft. The requirements include performing visual and detailed inspections of the blades according to specified instructions from Hartzell Alert Service Bulletin (ASB) HC-ASB-61-265, and removing any cracked blades from service immediately. The AD was issued under the Civil Aviation Safety Regulations 1998 and became effective on 25 December 2003, with compliance timelines varying based on the inspection type and condition of the propeller blades. This AD extends to the Commonwealth of Australia and is published in the Commonwealth of Australia Gazette to ensure its nationwide applicability and enforceability.

Key Provisions

This Airworthiness Directive (AD) primarily pertains to Hartzell Propeller Inc. model HC-A6A-3 series propellers equipped with A10460 series composite blades. It mandates a series of inspections and actions to mitigate the risk of blade cracking and subsequent in-flight separation, which could lead to significant damage and loss of control of the aircraft (subregulation 39.1(1) of CASR 1998). Specifically, the directive requires the performance of a visual inspection of the A10460 series composite propeller blades for cracks as per Para 3A Accomplishment Instructions of Hartzell Alert Service Bulletin (ASB) HC-ASB-61-265, followed by a more detailed inspection according to Para 3B Accomplishment Instructions of Hartzell ASB HC-ASB-61-265. If any cracks are found, the affected blade must be removed from service immediately. The inspections must be conducted within 100 propeller flight hours or 30 days from the effective date of the AD, whichever comes first, and then at intervals not exceeding 300 propeller flight hours. The second inspection must be conducted at each overhaul of the propeller, while the removal of any cracked blade from service must occur before further flight. The AD imposes several obligations on the operators and maintainers of the affected aircraft. They must ensure that the visual and detailed inspections of the propeller blades are conducted as specified in the directive. This involves following the specific instructions outlined in the referenced Hartzell Alert Service Bulletins to accurately identify any potential cracks. Operators and maintainers must also remove any blades found to be cracked from service before further flight, which may necessitate scheduling maintenance or repairs to the aircraft. Compliance with the inspection intervals is mandatory, and failure to adhere to these requirements could lead to unsafe conditions that may not be detected until a more severe incident occurs. Failure to comply with the requirements of this Airworthiness Directive can result in significant consequences. The primary risk is the potential for in-flight separation of a cracked propeller blade, which could lead to severe damage to the aircraft and endanger lives. From a regulatory perspective, non-compliance with ADs is considered a breach of the Civil Aviation Safety Regulations (CASR). Depending on the severity and intent of the non-compliance, this could result in both civil and criminal penalties. For individuals, the potential penalties may include fines and imprisonment, while corporate entities could face even higher fines. The exact penalties would be determined based on the specific circumstances and the discretion of the court. The AD becomes effective on 25 December 2003, and it is published in the Commonwealth of Australia Gazette on 3 December 2003 to ensure that all relevant parties are duly informed.