AD/HU 369/39 - Tail Rotor Control Bellcrank Supports - Inspection and Modification

Overview

The Civil Aviation Regulations 1998 were enacted by the Commonwealth of Australia to regulate civil aviation safety, ensuring the safe operation of aircraft and the protection of life and property. One particular regulation, AD/HU 369/39, was introduced to address the problem of cracks developing in the tail rotor control bellcrank supports of McDonnell Douglas (Hughes) and Kawasaki 369 Series Helicopters, which could potentially compromise the safety of these aircraft. This regulation was developed by the Civil Aviation Safety Authority and mandates specific inspection and modification procedures for affected helicopters to prevent such failures, thereby aligning with the overarching policy objective of maintaining high safety standards in civil aviation. This legislative instrument, issued under the authority of the Civil Aviation Act 1988, requires all 500 model 369 series helicopters and specific 500D models to undergo inspections within 25 hours after 17 July 1979 and subsequently at 100-hour intervals until modifications are made according to the specified requirement documents. The aim is to ensure the continued airworthiness and safety of these helicopters by addressing the identified issue with the tail rotor control bellcrank supports.

Scope and Application

The Civil Aviation Regulations 1998, specifically PART 39 - 105, applies to all McDonnell Douglas (Hughes) and Kawasaki 369 series helicopters, encompassing both the 500 model and the 500D model with specified serial numbers. The legislation mandates an inspection and potential modification of the tail rotor control bellcrank supports to ensure airworthiness. This inspection must be conducted within 25 hours of time in service following 17 July 1979 and subsequently at 100-hour intervals until the specified modifications are made according to the relevant requirement documents, Hughes SIN No. HN-139 for Model 500 and Hughes SIN No. DN-49 for Model 500D. The geographic reach of this regulation is national, as it is a Commonwealth regulation, applying uniformly across Australia. The regulation does not specify any exclusions or exemptions but mandates compliance for all specified aircraft to mitigate the risk of cracks developing in the tail rotor control bellcrank supports at STN. 142.

Key Provisions

The main operative sections of this legislation, specifically Civil Aviation Regulation 1998, Part 39 - 105, require specific actions to be taken with respect to the airworthiness of certain McDonnell Douglas (Hughes) and Kawasaki 369 series helicopters. Section 39-105 (AD/HU 369/39) mandates the inspection and, if necessary, the modification of the tail rotor control bellcrank supports for all 500 model 369 series helicopters and specific 500D model 369D helicopters (section 39-105(1)). The inspection must occur within 25 hours of time in service after 17 July 1979 and then at 100-hour intervals until the modification to Part II of the relevant requirement document is completed (section 39-105(2)). This is to ensure that any cracks that may develop in the tail rotor control bellcrank supports are identified and rectified to maintain the airworthiness of these helicopters. The obligations and requirements imposed by the Civil Aviation Regulations 1998 on the parties or entities governed by this legislation are clear and specific. Operators of the affected helicopters must ensure that inspections are conducted within the stipulated timeframes, as outlined in the regulation (section 39-105(1)). These inspections must be thorough and comply with the guidelines set forth in Hughes SIN No. HN-139 for Model 500 and Hughes SIN No. DN-49 for Model 500D (section 39-105(2)). If any cracks are detected during the inspection, the operator must then proceed with the modifications as specified in Part II of the relevant requirement document (section 39-105(3)). Failure to comply with these obligations could result in the aircraft being deemed unairworthy, posing a significant risk to safety. Failure to comply with the requirements set out in the Civil Aviation Regulations 1998 could lead to various consequences. The Civil Aviation Safety Authority (CASA) has the authority to enforce penalties and take legal action against non-compliant operators. Under section 39-105, any operator who fails to adhere to the inspection and modification requirements may face civil or criminal penalties. The maximum penalties for such breaches are not explicitly stated in the legislation, but they could include fines, imprisonment, or both, depending on the severity of the non-compliance. Additionally, the operator could be subject to enforcement actions such as suspension or revocation of their operating certificate, which would prevent them from legally operating the affected aircraft until compliance is achieved.