AD/A109/17 Amdt 1 - Main Gearbox Gleason Crown Bolts

Overview

The Civil Aviation Regulations 1998, as amended by the Legislative Instrument F2006B01801, specifically address the maintenance and safety requirements for the Agusta A109 Series Helicopters. Enacted by the Commonwealth of Australia, this regulation was introduced to ensure the safety and airworthiness of the A109A and A109 AII helicopters. The Civil Aviation Safety Authority (CASA) issued this directive to address an identified issue with the main gearbox Gleason crown bolts in these helicopters, which were found to have a potential for shearing, leading to safety concerns. The objective of this regulation is to mandate the replacement of these bolts to prevent such failures and maintain the structural integrity of the helicopters. The directive applies to all A109A and A109 AII helicopters within specified serial numbers and gearbox serial numbers, with certain exclusions noted. Compliance with this directive is crucial to ensure the safety of flight operations involving these aircraft. The regulation specifies the requirements and timelines for the replacement of the Gleason crown bolts, depending on the time in service of the main gearbox. For gearboxes with less than 1100 hours’ time in service, the replacement must occur before reaching 1200 hours’ time in service or by 31 January 1994, whichever comes first. For gearboxes with more than 1200 hours’ time in service, the replacement must be carried out within 300 hours’ time in service from 1 April 1993 or by 31 January 1994, whichever occurs first. This directive references the mandatory Agusta Bollettino Tecnico No 109-77 Rev A and an Italian Airworthiness Directive (RAI AD 92-400) for compliance guidelines. The regulation was prompted by findings during routine maintenance where magnesium flakes were detected, leading to the discovery of sheared bolts in the Gleason Crown assembly.

Scope and Application

The Civil Aviation Regulations 1998, specifically Part 39 - 105 concerning the Civil Aviation Safety Authority’s schedule of airworthiness directives, apply to all A109A and A109 AII helicopters up to and including aircraft serial number 7437 that are fitted with certain main gearboxes. This legislation mandates that unless previously completed, the Gleason crown bolts in specified main gearboxes must be replaced according to Agusta Bollettino Tecnico No 109-77 Rev A. It is important to note that certain main gearbox serial numbers are already compliant with this directive. The compliance timeline requires that for gearboxes with less than 1100 hours of service, the replacement must be carried out before reaching 1200 hours or by 31 January 1994, whichever comes first. For gearboxes with more than 1200 hours of service, the replacement must occur within 300 hours or by 31 January 1994, whichever comes first. This directive extends its applicability nationally within Australia, ensuring uniformity in aviation safety standards across the country.

Key Provisions

The Civil Aviation Regulations 1998, specifically Part 39, includes a schedule of airworthiness directives that govern the maintenance and operation of certain aircraft, including Agusta A109 Series Helicopters. One such directive, AD/A109/17 Amendment 1, pertains to the main gearbox Gleason crown bolts of A109A and A109 AII helicopters with certain serial numbers and gearboxes. The directive mandates the replacement of Gleason crown bolts in the main gearbox to ensure airworthiness. This is to be carried out in accordance with Agusta Bollettino Tecnico No 109-77 Rev A, referencing RAI AD 92-400 for additional guidance. The applicability of AD/A109/17 Amendment 1 extends to all A109A and A109 AII helicopters with specified serial numbers and gearboxes, excluding those with certain serial numbers which are already compliant. The requirement is to replace the Gleason crown bolts in the main gearbox before the gearbox reaches a certain number of service hours or by a specified date, depending on the current service hours of the gearbox at the time of the amendment’s issuance. Specifically, for gearboxes with less than 1100 hours’ time in service, the replacement must occur before reaching 1200 hours or by 31 January 1994, whichever is earlier. For gearboxes with more than 1200 hours’ time in service, the replacement must occur within 300 hours of service from 1 April 1993 or by 31 January 1994, whichever is earlier. Operators and owners of affected helicopters must ensure compliance with AD/A109/17 Amendment 1 by replacing the Gleason crown bolts as required. Failure to comply with this directive could result in the helicopter being deemed unairworthy, which could lead to severe operational restrictions or prohibitions. The directive is critical for maintaining the structural integrity of the main gearbox and preventing potential in-flight failures that could compromise safety. There are no specific offences, penalties, or consequences detailed in the directive itself for non-compliance. However, under the Civil Aviation Act 1988, non-compliance with airworthiness directives can lead to civil penalties, including fines, and criminal charges for operators who knowingly permit an aircraft to be used in a manner that contravenes regulations. The severity of penalties can vary based on the circumstances and the impact of the non-compliance on aviation safety.