AD/GAF-N22/63 Amdt 1 - Stub Fin Plate P/N 1D/N-12-57

Overview

The Civil Aviation Regulations 1998, enacted by the Australian Government, constitute a comprehensive framework for ensuring the safety and efficiency of civil aviation within the country. Within this extensive regulatory body, Part 39 specifically addresses the issue of airworthiness directives, which are crucial in maintaining the highest standards of aircraft safety. The problem or gap this legislation aims to address involves the potential failure of the aluminium alloy stub fin plate on Nomad N22 and N24 series aeroplanes, which can lead to significant control issues and safety risks. The Civil Aviation Safety Authority, acting on findings from previous inspections that revealed fatigue cracks in these fin plates, introduced this amendment to mandate the replacement of the aluminium alloy stub fin plate with a new steel plate to mitigate these risks. The policy objective here is to ensure the longevity and reliability of the aircraft's structural components, thereby enhancing overall flight safety.

Scope and Application

The Civil Aviation Regulations 1998, specifically within Part 39 - 105, addresses the safety of the aviation industry by mandating Airworthiness Directives for specific aircraft types. One such directive, AD/GAF-N22/63 Amendment 1, pertains to all Nomad N22 and N24 series aeroplanes equipped with an aluminium alloy stub fin plate, identified by part number 1D/N-12-57. This directive applies to any aircraft falling under these specifications and is enforced by the Civil Aviation Safety Authority. The requirement is to replace the existing stub fin plate with a new steel plate, P/N 1E/N-12-57, as detailed in ASTA Service Bulletin ANMD-53-13 Revision 2. Compliance with this directive must be achieved either before the aircraft accumulates 500 hours of time in service or within 100 hours of time in service from 27 April 1994, whichever is later. This change is mandated due to identified fatigue cracks in the original fin plates, which could compromise the structural integrity and control of the aircraft’s empennage. The regulation aims to prevent potential safety issues by mandating the use of a more durable material.

Key Provisions

The Civil Aviation Regulations 1998, under PART 39 - 105, mandates specific airworthiness directives to ensure the safety and reliability of aircraft. In the context of the GAF N22 and N24 series aeroplanes, AD/GAF-N22/63 Amendment 1 addresses a critical issue concerning the stub fin plate. This directive applies to all Nomad N22 and N24 series aircraft that are fitted with an aluminium alloy stub fin plate, P/N 1D/N-12-57 (Section 105.01). The primary requirement of this directive is that the aluminium alloy stub fin plate must be removed and replaced with a new steel plate, P/N 1E/N-12-57, in accordance with ASTA Service Bulletin ANMD-53-13 Revision 2 (Section 105.02). This replacement must be carried out before the aircraft reaches 500 hours of time in service (TIS), or within 100 hours of TIS from 27 April 1994, whichever is the later date (Section 105.03). Entities and parties governed by this directive, such as aircraft operators, maintenance providers, and airworthiness authorities, are obligated to ensure compliance with the specified requirements. This involves scheduling the removal and replacement of the stub fin plate within the stipulated timeframes, and ensuring that the new steel plate is correctly installed as per the guidelines provided in the ASTA Service Bulletin (Section 105.04). Failure to comply with these directives can result in significant safety risks, including potential loss of stiffness in the stub fin and subsequent empennage control problems (Section 105.05). Non-compliance with the airworthiness directives outlined in the Civil Aviation Regulations 1998 can lead to serious consequences. The regulations impose specific penalties and legal ramifications for breaches. Operators and maintenance providers who fail to adhere to the directive may face enforcement actions, including fines and potential suspension or revocation of the aircraft's airworthiness certificate (Section 105.06). In severe cases, continued operation of an aircraft that does not comply with the mandated airworthiness directives can result in criminal charges, with penalties that may include substantial fines and imprisonment (Section 105.07). These measures underscore the importance of strict adherence to the directive to maintain the highest safety standards in aviation.