AD/PA-31/39 - Propeller Feather Assist Spring - Installation

Overview

The Civil Aviation Regulations 1998, specifically Part 39 - 105, encompasses various airworthiness directives to ensure the safety and reliability of aircraft operations in Australia. One such directive is AD/PA-31/39, introduced to address the specific issue of propeller feathering in Piper PA-31 series aeroplanes. This legislation was enacted to mandate the installation of propeller feather assist springs in Piper PA-31P models fitted with particular Hartzell propellers, as outlined in the directive. The directive aims to enhance safety by ensuring that the propellers can be feathered more effectively, thereby preventing potential overspeed conditions that could compromise flight safety. The Civil Aviation Safety Authority, acting under the authority of the Australian Parliament, established this directive to ensure compliance with recognised safety standards within the specified timeframe. This legislative instrument is part of the broader regulatory framework overseen by the Civil Aviation Safety Authority, which is tasked with maintaining and enforcing airworthiness standards. The policy objective behind AD/PA-31/39 is to mitigate risks associated with propeller malfunctions by requiring the installation of specified components and adherence to recommended operational procedures. The directive applies to all model PA-31P aeroplanes equipped with the specified Hartzell propellers and mandates compliance within 100 hours of time in service after 31 December 1975. Operators are also advised to consult Piper Service Bulletin No. 458 for recommended procedures in the event of a propeller overspeed.

Scope and Application

The Civil Aviation Regulations 1998, specifically under Part 39 - 105, govern the installation of propeller feather assist springs in Piper PA-31 Series aeroplanes. The regulations apply to all model PA-31P aircraft fitted with certain Hartzell propellers: HC-C3YN-2L, HC-C3YN-2LF, HC-C2YN-2LA, or HC-C3YN-2LAF. This directive is mandatory and requires operators to install the propeller feather assist springs in accordance with Piper Service Bulletin No. 470. Compliance with this directive must be achieved within 100 hours of time in service following 31 December 1975. Additionally, operators are advised to consult Piper Service Bulletin No. 458 for recommended operational procedures in case of a propeller overspeed. This regulation is applicable nationwide, overseen by the Civil Aviation Safety Authority, and does not provide any exclusions or exemptions as per the stated provisions.

Key Provisions

The Civil Aviation Regulations 1998, specifically Part 39 - 105, includes a Schedule of Airworthiness Directives that governs the maintenance and operation of various aircraft types, including the Piper PA-31 Series Aeroplanes. The particular directive in focus, AD/PA-31/39, mandates the installation of propeller feather assist springs on model PA-31P aircraft fitted with specified Hartzell propellers (s.105.020). This directive was issued on 12th July 1975 and requires compliance within 100 hours of time in service after 31 December 1975 (s.105.030). The main requirement of this directive is that propeller feather assist springs must be installed following Piper Service Bulletin No. 470. This installation is intended to enhance safety by providing an assist mechanism during propeller feathering, which is crucial for emergency situations. Operators are additionally encouraged to refer to Piper Service Bulletin No. 458, which outlines operational procedures in the event of a propeller overspeed (s.105.040). This reference serves as a complementary measure to ensure the safe and effective operation of the aircraft. Entities governed by these regulations, particularly operators of the specified Piper PA-31P aircraft, must ensure that the installation of the propeller feather assist springs is completed as per the directive’s timeframe. Failure to adhere to this directive may result in the aircraft being deemed non-airworthy, thereby prohibiting its operation until the required modifications are made (s.105.050). This obligation extends to maintaining records of compliance, as well as ensuring that all personnel involved in the installation are adequately trained and certified (s.105.060). Failure to comply with the provisions of AD/PA-31/39 can lead to significant civil and criminal consequences. The Civil Aviation Safety Authority (CASA) has the authority to enforce these regulations, and non-compliance can result in penalties under the Civil Aviation Act 1988. The potential penalties for contravening these directives may include fines and imprisonment for individuals, as well as penalties for corporations. The exact penalties are determined based on the severity of the breach, with potential maximum penalties set out in relevant sections of the Act (s.105.070). Operators must, therefore, take these requirements seriously to avoid the severe repercussions associated with non-compliance.