AD/PHZL/67 - Propeller Blade Cracking

Overview

The Civil Aviation Regulations 1998, as amended, include provisions for airworthiness directives to address safety concerns within the aviation sector. The 1998 Regulations were enacted by the Australian Parliament to regulate civil aviation and ensure the safety and efficiency of air operations. One such directive, AD/PHZL/67, targets Hartzell propellers, specifically the HC-B3TN, HC-B5MP, HC-E4A, and HC-D4N series manufactured between March 1992 and June 1996. The directive was introduced to address the problem of blade cracking in these propellers, which could lead to in-flight blade separation, thereby posing a significant safety risk. The directive mandates inspections and repairs to prevent such failures, with specific compliance timelines depending on the type of aircraft the propeller is installed on. The policy objective is to ensure the continued airworthiness of these propellers and mitigate the risk of in-flight failures.

Scope and Application

The Civil Aviation Regulations 1998, specifically Part 39 - 107, includes Airworthiness Directives that apply to particular types of aircraft propellers. This legislation targets Hartzell HC-B3TN, HC-B5MP, HC-E4A, and HC-D4N series propellers with blades identified by serial numbers and manufactured between March 1992 and June 1996, installed on various aircraft such as the Air Tractor AT series, Antonov AN-28 series, Ayres S2R series, and others. The directive is aimed at preventing propeller blade separation due to blade shank cracks originating from forging flaws. Compliance with the Hartzell Alert Service Bulletin HC-ASB-61-220 dated July 1996 is required. Depending on the type of aircraft the propeller is installed on, compliance must occur within a specified time frame after the directive's effective date of 23 August 1996. For agricultural or acrobatic aircraft, compliance is required within 10 hours of service, while for all other aircraft it must occur within 60 hours of service. Additionally, if a propeller has not yet complied and experiences sudden or unusual vibration, further flight is prohibited until compliance is achieved.

Key Provisions

The Civil Aviation Regulations 1998, specifically Part 39 - 107, mandate that all Hartzell HC-B3TN, HC-B5MP, HC-E4A, and HC-D4N series propellers, manufactured between March 1992 and June 1996, be inspected to prevent propeller blade separation due to blade shank cracks emanating from forging flaws. These propellers are installed on a range of aircraft including the Air Tractor AT-502, AT-503, and AT-802 series, Antonov AN-28 series, Ayres S2R series, Douglas DC-3 (STC modified), Aerospatiale (Nord) 262 (Mohawk) series, Norman Aeroplanes NAC-6 series, Pilatus PC-7 mk II, PC-9, and PC 12 series, PZL PZL-M18 (STC Modified), Shorts Brothers plc S-312 Tucano (Military), SD3, and C-23 (Military) series, and Twin Commander 690 and 695 series (STC Modified). Compliance with AD/PHZL/67 is required to follow Hartzell Alert Service Bulletin HC-ASB-61-220 dated July 8/96, as referenced in FAA AD 96-15-04 Amdt 39-9697. These regulations impose specific obligations on aircraft operators and owners to ensure their propellers are compliant. For propellers installed on agricultural or acrobatic aircraft, compliance must be achieved within 10 hours of time in service from the effective date of 23 August 1996. For all other aircraft, compliance must occur within 60 hours of time in service from the same effective date. Additionally, any propeller that has not previously complied with these requirements and experiences a sudden or unusual vibration must be inspected and addressed before further flight. Failure to comply with the requirements set out in the Civil Aviation Regulations 1998 can lead to significant consequences. These can include civil penalties for non-compliance with airworthiness directives, which can vary but are substantial. Additionally, operating an aircraft with non-compliant propellers can result in criminal penalties if the non-compliance is deemed to have contributed to an aviation accident or incident. The exact penalties are detailed in the Civil Aviation Act 1988, which provides for fines and imprisonment for serious breaches. The potential for such penalties underscores the importance of strict adherence to the requirements outlined in the airworthiness directives.