AD/BN-2/63 - Nacelle Box Structure at Bottom Fitting of MLG

Overview

The Civil Aviation Regulations 1998, enacted by the Parliament of the Commonwealth of Australia, serve to regulate civil aviation safety across the nation. This legislation is part of a broader effort to ensure that all aspects of civil aviation maintain high safety standards. One specific instance of this is found in Part 39, which addresses airworthiness directives, such as AD/BN-2/63, issued to mitigate safety risks. This directive, introduced to address the issue of threadbound bolts in the main landing gear bottom fitting of Pilatus Britten-Norman BN-2 Series Aeroplanes, aims to prevent potential structural failures that could compromise flight safety. By mandating inspections in accordance with the relevant service bulletin, the policy objective is to ensure that all affected aircraft are maintained to the required safety standards, thus protecting both the crew and passengers. The enactment of this directive by the Civil Aviation Safety Authority underscores the commitment to maintaining stringent safety measures in civil aviation. The specific requirement to inspect the nacelle box structure at the bottom fitting of the main landing gear within 50 landings after the directive's effective date of 21 May 1998, aims to preemptively address issues that could lead to significant structural damage. This regulatory measure is crucial in maintaining the integrity and safety of the aircraft, thereby ensuring compliance with the overarching policy objective of safeguarding lives and property in the aviation sector.

Scope and Application

The Civil Aviation Regulations 1998, specifically Part 39 - 105, pertains to the Civil Aviation Safety Authority's (CASA) Schedule of Airworthiness Directives, which include the directive AD/BN-2/63 concerning the nacelle box structure at the bottom fitting of the main landing gear (MLG) for Pilatus Britten-Norman BN-2 series aeroplanes. This directive applies to all models of the BN-2 series, including BN-2, BN-2A, BN-2B, and BN2T Islanders. The directive mandates that inspections be conducted in accordance with Pilatus Britten-Norman Mandatory Service Bulletin BN2/SB.235, with compliance required unless already completed, within 50 landings following 21 May 1998. This airworthiness directive became effective on 21 May 1998. The directive's purpose is to address the issue of threadbound bolts at the main landing gear bottom fitting, which can lead to play and subsequent cracks in the nacelle box structure, a problem previously highlighted in AD/BN-2/61.

Key Provisions

The Civil Aviation Regulations 1998, Part 39 - 105, under the Civil Aviation Safety Authority’s Schedule of Airworthiness Directives, includes specific regulations for Pilatus Britten-Norman BN-2 Series Aeroplanes. One such directive, AD/BN-2/63, focuses on the nacelle box structure at the bottom fitting of the main landing gear (MLG) (s.1). The directive mandates that all Model BN-2, BN-2A, BN-2B, and BN2T Islanders must undergo an inspection as per the Pilatus Britten-Norman Mandatory Service Bulletin BN2/SB.235. This inspection should be completed within 50 landings following 21 May 1998, unless it has already been performed (s.2). The directive imposes specific obligations on aircraft operators and maintenance personnel. They must ensure that the inspection is conducted according to the guidelines outlined in the service bulletin. This involves checking the condition of the attachment bolts at the MLG bottom fitting and ensuring that there are no signs of thread binding or cracks in the nacelle box structure. Failure to comply with these inspection requirements can lead to significant safety risks, potentially compromising the structural integrity of the aircraft during flight (s.3). Breaches of the requirements set forth in AD/BN-2/63 can result in serious consequences. The Civil Aviation Safety Authority may impose penalties on operators and maintenance personnel who fail to adhere to the inspection mandates. These penalties can include fines and other administrative actions, with the potential for more severe consequences if the non-compliance leads to safety incidents. Additionally, operators may face legal actions if the non-compliance is found to be a contributing factor in an accident or incident (s.4). The directive emphasises the importance of timely and thorough inspections to prevent the risks associated with threadbound bolts and related structural issues (s.5).