AD/BELL 47/62 Amdt 2 - Centre Fuselage Frame Assembly

Overview

The Civil Aviation Regulations 1998, specifically PART 39 - 105 Civil Aviation Safety Authority Schedule of Airworthiness Directives, addresses the issue of ensuring the airworthiness of the Bell Helicopter Textron 47 (all variants) series helicopters. Enacted by the Commonwealth of Australia, this legislation aims to maintain the highest safety standards in the aviation industry by providing detailed directives for the maintenance and inspection of specific components of the aircraft. The policy objective behind these regulations is to prevent airworthiness issues that could potentially lead to safety hazards, thereby protecting the lives of passengers and crew, as well as the general public. This particular legislative instrument, AD/BELL 47/62 Amendment 2, focuses on the inspection of the fuselage frame assembly for internal corrosion, which is critical for the structural integrity of the helicopter. The requirement for radiographic inspection and the periodicity of such inspections are outlined to ensure ongoing compliance with safety standards. The specific problem this legislation addresses is the corrosion of fuselage frame assembly tubes in Bell 47 series helicopters, which was identified through a survey of radiographic results and defect reports. By mandating regular inspections and specifying the use of approved techniques, the regulations aim to mitigate the risks associated with tube corrosion. The requirement for inspections within five years from the date of manufacture and at intervals not exceeding six years underscores the importance of proactive maintenance in preventing corrosion-related failures. This amendment was introduced to reflect the improved control over tube corrosion issues, allowing for a relaxation in the frequency of inspections while maintaining rigorous safety standards.

Scope and Application

The Civil Aviation Regulations 1998, as amended, under the jurisdiction of the Civil Aviation Safety Authority, mandate specific airworthiness directives for certain aircraft models. Particularly, Part 39 - 105 pertains to Bell Helicopter Textron 47 (all variants) series helicopters, as outlined in AD/BELL 47/62 Amendment 2 dated 5/87. This directive applies to all model 47D, 47G, and 47J series helicopters. The primary requirement is the inspection of specified fuselage frame assembly tubes for internal corrosion using approved techniques, with particular attention to areas such as the engine basket pick-up junction, lower longerons, upper longerons, and additional components for certain models. The inspection must be conducted within five years from the date of manufacture and then at intervals not exceeding six years. This regulation ensures that any detected corrosion is thoroughly assessed to determine its extent, including inspecting the entire length of affected tubes and samples of adjacent tubes. The geographic reach of this legislation is nationwide, covering all helicopters of the specified models operating within Australia. The regulations do not specify any exclusions or exemptions but rely on subordinate instruments to provide further detail on acceptable inspection techniques and compliance measures.

Key Provisions

The Civil Aviation Regulations 1998, Part 39 - 105, specifically address the airworthiness directives for Bell Helicopter Textron 47 series helicopters, with Amendment 2 (AD/BELL 47/62) focusing on the inspection of the centre fuselage frame assembly. The key sections of this directive (sections (a)-(d)) detail the specific areas of the fuselage that must be inspected for internal corrosion. These areas include the three main side tubes at the engine basket pick-up junction, the centre of the lower longerons, and sections of the upper longerons adjacent to the engine pick-up basket. For model 47D and 47G helicopters, additional inspection of the first cross tube in the tail boom structure and the forward ends of the upper tail boom longerons is also required. Under this directive, operators and owners of the specified Bell 47 helicopter models are required to inspect the designated fuselage frame assembly tubes for internal corrosion using specified techniques such as radiographic, DCA/NDI/R/3A, or other methods approved by the Secretary. These inspections must occur within five years from the date of manufacture and thereafter at intervals not exceeding six years. The directive mandates that the inspected length of each tube must be no less than 25.4 cm (10 inches). If corrosion is detected in any tube, the entire length of the affected tube and sample lengths of adjacent tubes must be inspected to determine the extent of the corrosion. Failure to comply with these airworthiness directives may result in the aircraft being deemed unairworthy, which can lead to significant operational disruptions and potential safety hazards. While the specific penalties for non-compliance are not detailed within the provided text, it is clear that adherence to these inspection requirements is mandatory to ensure the continued airworthiness of the affected helicopters. In summary, the Civil Aviation Regulations 1998 require operators of Bell 47D, 47G, and 47J helicopters to perform regular inspections of specified fuselage frame assembly tubes for internal corrosion. These inspections must be conducted within five years of the helicopter's manufacture and every six years thereafter. Compliance is essential to maintain the airworthiness of the aircraft, and failure to adhere to these requirements could result in serious consequences, including the grounding of the aircraft.