AD/PA-34/29 Amdt 2 - Main Wing Spar Attaching Nuts

Overview

The Civil Aviation Regulations 1998, specifically Part 39 - 105, was enacted to ensure the safety of civil aviation in Australia, addressing gaps in the regulation of aircraft maintenance and airworthiness. This regulation, under the authority of the Civil Aviation Safety Authority, was introduced to address safety issues identified in specific aircraft models, such as the Piper PA-34 (Seneca) series aeroplanes. The regulation mandates detailed visual inspections of nuts fitted to the wing spar attaching bolts to prevent in-flight failure due to cracking or splitting, which could lead to catastrophic consequences. The policy objective is to maintain and enhance the safety standards of civil aviation by requiring timely and thorough inspections and maintenance of critical components. The Piper PA-34 series directive, Amendment 2, was implemented following reports of split nuts found on an aircraft outside the initially affected range. This amendment requires repetitive inspections on all models, ensuring that any defective nuts are replaced before further flight. The regulation emphasises the importance of using a sight aid where possible to conduct these inspections, although it acknowledges difficulties in accessing certain areas. Compliance with these directives is mandatory, with inspections required at specific intervals post the effective date of 9 August 1989, ensuring the ongoing safety and airworthiness of the aircraft.

Scope and Application

The Civil Aviation Regulations 1998, specifically PART 39 - 105, mandates that all Piper PA-34 (Seneca) series aeroplanes, regardless of their model or serial number, must comply with Airworthiness Directives concerning the inspection and replacement of main wing spar attaching nuts. This applies to all aircraft within the Commonwealth of Australia, governed by the Civil Aviation Safety Authority. The directive requires a detailed visual inspection of the nuts to check for cracks or splits, with defective nuts to be replaced before further flight. The requirement is that inspections must be completed within 25 hours of time in service after 9 August 1989, and subsequently at each scheduled inspection for the issue of a Maintenance Release, unless already done within 75 hours prior to that date. This directive extends its reach to ensure compliance through the specified inspection and replacement protocol, as recommended by Piper Service Bulletin No. 602. Although Amendment 2 has removed the requirement for 10X magnification during inspection due to accessibility issues, the use of a sight aid is still strongly recommended for better visibility.

Key Provisions

The Civil Aviation Regulations 1998, under Part 39 - 105, establish specific safety directives for various aircraft models, with particular focus on the Piper PA-34 (Seneca) series aeroplanes. The directive AD/PA-34/29 Amendment 2 pertains to the main wing spar attaching nuts of these aircraft. The requirement, as outlined in the regulation, is that a detailed visual inspection must be performed on the nuts fitted to the wing spar attaching bolts (section 1). This inspection is to check for any cracks or splits in the nuts, which, if detected, must be replaced before any further flight is undertaken. Compliance with this directive is stringent. Operators of Piper PA-34 series aircraft must ensure that the visual inspection of the nuts is completed within 25 hours of time in service after the specified date of 9 August 1989, and thereafter at each scheduled inspection for the issuance of a Maintenance Release. It is important to note that if the inspection has not been performed within the 75 hours of time in service prior to 9 August 1989, the inspection must be done within the 25 hours of time in service post this date, and then at each subsequent scheduled inspection (section 1). The obligation imposed on the operators is to meticulously follow the inspection schedule and ensure that any defective nuts are replaced promptly to maintain airworthiness. This directive follows a safety report where six split nuts were discovered on an Australian aircraft, leading to the initial Amendment 1 of this directive. This amendment was later revised in Amendment 2 to address issues with accessibility and to remove the requirement for 10X magnification, while still recommending the use of a sight aid where possible to facilitate the inspection process. Failure to comply with the requirements set out in the AD/PA-34/29 Amendment 2 may result in serious safety concerns, potentially leading to operational restrictions or penalties under the Civil Aviation Act 1988. The specific consequences for non-compliance would depend on the severity of the breach and the findings of any subsequent investigation by the Civil Aviation Safety Authority. The emphasis is on ensuring the safety of flights through regular and rigorous inspections, as outlined in the directive.