AD/PA-25/4 - Front Spar Attachment Fittings - Modification

Overview

The Civil Aviation Regulations 1998, enacted by the Commonwealth of Australia, aims to ensure the safety of civil aviation operations within the country. One specific directive under Part 39, titled "Civil Aviation Safety Authority Schedule of Airworthiness Directives," addresses the safety of Piper PA-25 (Pawnee) Series Aeroplanes through AD/PA-25/4. This directive was introduced to address the identified safety issue concerning the front spar attachment fittings of the specified model and variants. The requirement involves modifying the steel front spar fittings and ensuring the dimensional tolerances of the fuselage wing attachment brackets meet the specified standards to prevent structural failure and ensure compliance with safety regulations. The policy objective is to maintain the airworthiness of these aircraft, thereby enhancing the safety of civil aviation.

Scope and Application

The Civil Aviation Regulations 1998, particularly Part 39 - 105 under the Civil Aviation Safety Authority, applies to a specific series of Piper PA-25 aeroplanes, namely those with serial numbers ranging from 25-1 to 25-619, 25-622, 25-623, 26-625, and 25-626. The regulations mandate the installation of steel front spar fittings, P/N 60113-00 and 60113-01, and close tolerance AN177-21A spar hinge bolts in accordance with Piper Service Bulletin No. 206. Additionally, the diameter of the holes in the fuselage wing attachment brackets, P/N 61005-00 and 61006-00, must be checked to ensure they fall within the specified tolerance of 0.437 inches minimum and 0.439 inches maximum. If the holes are larger, the brackets must be restored to within these tolerances by reaming and bushing as detailed in the regulations. The requirement also notes that aeroplanes with steel spar fittings manufactured by the Commonwealth Aircraft Corporation are considered compliant if they are fitted with close tolerance AN177-21A bolts and conform to the specified dimensional tolerances. Compliance with these directives is mandatory for the specified aircraft models, ensuring adherence to safety standards set by the Civil Aviation Safety Authority.

Key Provisions

The Civil Aviation Regulations 1998, specifically in Part 39 - 105, impose stringent requirements on the maintenance and modifications of Piper PA-25 (Pawnee) Series Aeroplanes under the Airworthiness Directive AD/PA-25/4. This directive (section 9/61) mandates the installation of specific steel front spar fittings (section 1) and close tolerance AN177-21A spar hinge bolts as per Piper Service Bulletin No. 206. Furthermore, it requires the verification of the dimensional tolerances of the holes in the fuselage wing attachment brackets, with a permissible diameter range of 0.437 inches minimum to 0.439 inches maximum. If the holes exceed this maximum, corrective measures must be taken by reaming the holes and inserting SAE 4130 steel bushes, followed by lining reaming to achieve the specified tolerances. These requirements are binding on all owners and operators of Piper PA-25 aircraft within the specified serial number range (sections 1 and 2). Compliance with these directives ensures that the structural integrity and airworthiness of the aeroplanes are maintained to the highest safety standards. Operators must ensure that all modifications and inspections are performed by appropriately certified personnel and that all components used meet the specified design and tolerance standards. Additionally, aeroplanes with steel spar fittings manufactured by the Commonwealth Aircraft Corporation are considered compliant if they are equipped with close tolerance AN177-21A bolts and adhere to the dimensional specifications outlined in the directive. Failure to comply with the provisions of this Airworthiness Directive may result in serious safety implications, as the directive is enforced by the Civil Aviation Safety Authority (CASA). Non-compliance can lead to severe civil and criminal penalties, including fines and potential imprisonment, depending on the severity of the breach and its impact on aviation safety. The specific penalties for non-compliance are determined by CASA and may include substantial financial penalties and legal action against the operators or individuals responsible for the non-compliance. It is imperative for all affected parties to adhere strictly to these requirements to avoid any legal repercussions.