AD/ENST 28/26 Amdt 2 - Tail Rotor Drive Shaft Couplings

Overview

The Civil Aviation Regulations 1998, under Part 39 - 105, incorporates the Civil Aviation Safety Authority's (CASA) Schedule of Airworthiness Directives to ensure the safety and airworthiness of aircraft operating within Australian airspace. This legislative instrument, specifically AD/ENST 28/26 Amendment 2, addresses issues related to the tail rotor drive shaft couplings of Enstrom F-28 Series Helicopters, particularly those equipped with part number 28-13609 couplings. The directive aims to ensure these components meet required safety standards by mandating inspections, lubrications, and material hardness checks, with specific timelines for compliance. This amendment responds to identified risks by incorporating updated manufacturer recommendations and enforcing stricter inspection protocols to mitigate potential hazards associated with the specified couplings. The Civil Aviation Regulations 1998, as amended, are enacted by the Australian Parliament to regulate the safety and airworthiness of civil aircraft. This particular directive, issued by CASA, targets a specific safety concern with Enstrom F-28 Series Helicopters, ensuring that maintenance procedures are rigorously followed. The policy objective is to enhance aviation safety by enforcing comprehensive inspection and maintenance requirements, thereby reducing the likelihood of in-flight failures or accidents related to the specified helicopter components.

Scope and Application

The Civil Aviation Regulations 1998, specifically Part 39 - 105, addresses the Airworthiness Directives for certain aircraft, including the Enstrom F-28 Series Helicopters. This particular directive, AD/ENST 28/26 Amendment 2, pertains to the tail rotor drive shaft couplings on Enstrom F-28A, 280, F28C, F-28C-2, 280C, F-28F and 280F models equipped with part number 28-13609 couplings. The directive applies to all aircraft within the specified models and part numbers, ensuring that the required maintenance and inspection procedures are followed to maintain airworthiness standards. The directive sets out specific requirements, including the disassembly and inspection of the couplings, lubrication, and material hardness checks, all to be carried out in accordance with the relevant Service Bulletin No. 0065 Rev B. Compliance with these procedures must be adhered to within specified timeframes, such as within 25 hours of service after 1 October 1983 or by 31 October 1983, and then every 600 hours or annually, whichever comes first. Failure to meet the material hardness test necessitates the retirement of the couplings from service, and those with more than 1200 hours of service must be retired within 50 hours of service after 31 January 1985.

Key Provisions

The Civil Aviation Regulations 1998, under Part 39, specifically Section 105, includes a schedule of airworthiness directives pertaining to Enstrom F-28 Series Helicopters, with a focus on AD/ENST 28/26 Amendment 2, which addresses the tail rotor drive shaft couplings. These directives apply to all F-28A, 280, F28C, F-28C-2, 280C, F-28F, and 280F models that are equipped with part number 28-13609 couplings. The requirements outlined in the directive include a series of maintenance and inspection procedures that must be followed for the safety of the aircraft and its passengers. The directive mandates that the couplings be disassembled and inspected according to Service Directive Bulletin No. 0065 Revision B, a process that must be completed within 25 hours of time in service after 1st October 1983 or by 31 October 1983, whichever comes first. This inspection must be repeated every 600 hours of time in service or annually, whichever is sooner. Additionally, the couplings must be partially disassembled and lubricated in line with Service Bulletin No. 0065 Revision B at each maintenance release inspection. A Rockwell "C" material hardness check must also be performed as per the same service bulletin, unless it has already been accomplished, prior to the issue of the next maintenance release after 31 January 1985. It is imperative that Aeroshell Grease 16 or 22, or an approved equivalent, be used for these procedures. Failure to comply with the stipulated requirements can result in significant consequences. Any coupling that fails the material hardness test must be retired from service immediately, and all couplings must be retired from service after accumulating 1200 hours of total time in service. For couplings that have more than 1200 hours of service time, retirement must occur within 50 hours of time in service following 31 January 1985. Non-compliance with these directives can lead to severe civil or criminal penalties, as the directives are designed to ensure the highest standards of aviation safety. The specific penalties for non-compliance are not detailed in the legislative instrument, but they may include fines, imprisonment, or both, as per the broader provisions of the Civil Aviation Act 1988.