Overview

The Piper PA-31 Series Aeroplanes Airworthiness Directive AD/PA-31/37 Amendment 10, issued under the Civil Aviation Regulations 1998, aims to ensure the safety of PA-31 series aircraft by establishing specific retirement lives for critical components. This legislative instrument, enacted by the Commonwealth of Australia, addresses the issue of airframe durability by specifying when certain parts of the aircraft must be retired to prevent structural failure due to fatigue. The policy objective is to maintain airworthiness and safety by mitigating the risk of airframe cracking, which increases with service hours and flights. The directive mandates that the wing main spar lower cap and pressure cabin (where applicable) be retired before exceeding specified times in service, with the remainder of the airframe to be retired after two wing main spar lower cap lifetimes. The directive provides a detailed retirement schedule for different models, exempting some from the wing fatigue life limitation if they adhere to specific engineering releases and inspection programs. The directive became effective on 25 February 1999, amending previous directives to remove the requirement for tracking average weight and flight times based on a sensitivity analysis by the Civil Aviation Safety Authority.

Scope and Application

The Piper PA-31 Series Aeroplanes Airworthiness Directive AD/PA-31/37 Amendment 10 applies to all models of Piper PA-31 series aircraft, which includes both civilian and commercial aeroplanes within Australia. This Civil Aviation Safety Authority directive, issued under the Civil Aviation Act 1988 and the Civil Aviation Regulations 1998, sets forth specific requirements for the retirement of certain components to ensure the continued airworthiness of these aircraft. The directive mandates the retirement of the wing main spar lower cap and the pressure cabin, if applicable, before the specified times in service or pressurised flight hours are exceeded, as detailed in the Retirement Schedule. The remainder of the airframe must be retired after the expiration of two wing main spar lower cap lifetimes. The directive applies nationally across Australia, overseen by the Commonwealth of Australia, and is enforced by the Civil Aviation Safety Authority. Certain aircraft modified in accordance with Gippsland Aeronautics Pty Ltd. Engineering Release PA31-0001 or PA31-0002 are exempt from the wing fatigue life limitation, although the airframe life limitation still applies. This directive extends its application through subordinate instruments to ensure compliance and safety standards are met across all relevant aircraft operations.

Key Provisions

The primary operative sections of this legislative instrument (AD/PA-31/37) establish specific requirements and timeframes for the retirement of various components of Piper PA-31 Series aeroplanes to ensure their continued airworthiness. Section 1 mandates the retirement of the wing main spar lower cap and the pressure cabin before exceeding the times in service specified in the Retirement Schedule (Section 2). The remainder of the airframe must be retired after the expiration of two wing main spar lower cap lifetimes (Section 2). These requirements apply to all models of Piper PA-31 series aeroplanes. The obligations imposed by this Act include ensuring that specific components of the aircraft are retired within the prescribed timeframes to mitigate the risk of airframe cracking. Operators and owners must adhere to the Retirement Schedule outlined in Section 2, which specifies the exact number of flight hours or pressurised flights after which certain components must be retired. For instance, the wing main spar lower cap for the PA-31-350 model must be retired after 13,000 flight hours, while the pressure cabin for the PA-31T1 model must be retired after 10,000 pressurised flights. Compliance with these requirements is mandatory and must be achieved forthwith, as stated in the Compliance section. Failure to comply with the provisions of this Act can result in severe consequences. The Civil Aviation Safety Authority (CASA) has the authority to enforce the regulations and take action against non-compliance. The maximum penalties for breaches of these regulations are not explicitly stated in the provided text, but they can include fines, suspension of airworthiness certificates, and potential grounding of the aircraft. These measures are intended to ensure the safety of air travel and prevent accidents caused by structural failure due to fatigue.