AD/ENST 28/22 - Main Rotor Transmission Mount Bolts - Inspection

Overview

The Civil Aviation Regulations 1998, administered by the Civil Aviation Safety Authority (CASA), were enacted to ensure the safety and efficiency of civil aviation in Australia. One specific regulation, AD/ENST 28/22, pertains to the inspection of main rotor transmission mount bolts for Enstrom F-28 Series Helicopters. This legislation was introduced to address a critical safety issue identified with the bolts of certain helicopter models, specifically the Enstrom F-28C and 280C, which were found to have defectively formed heads. The policy objective of this directive is to mitigate the risk of in-flight failures by mandating a thorough inspection of the specified bolts within 100 hours after 31 July 1979, as documented in Enstrom Service Directive Bulletin No. 0049. This proactive approach aims to enhance aviation safety by ensuring that all affected helicopters comply with the specified maintenance requirements.

Scope and Application

The Civil Aviation Regulations 1998, specifically Part 39 - 105, applies to all Enstrom F-28C helicopters with serial numbers 451-2 to 464-2, and all model 280C helicopters with serial numbers 1145 to 1169. This legislation mandates that these aircraft must comply with Airworthiness Directive AD/ENST 28/22, which concerns the inspection of the main rotor transmission mount bolts. The directive applies to the entire Commonwealth of Australia, ensuring that the prescribed maintenance action is carried out nationally. Compliance with this directive is required within 100 hours of time in service after 31 July 1979, as documented in Enstrom Service Directive Bulletin No. 0049. This regulation is specific to the mentioned serial numbers and does not apply to other aircraft models or serial numbers outside this scope. Any deviations or extensions in application would need to be addressed through subordinate instruments or further clarifications from the Civil Aviation Safety Authority.

Key Provisions

The Civil Aviation Regulations 1998, specifically Part 39 - 105, which pertains to the Civil Aviation Safety Authority's Schedule of Airworthiness Directives, includes AD/ENST 28/22 concerning Enstrom F-28 Series Helicopters (sections 1-5). This directive mandates the inspection of main rotor transmission mount bolts for all model F-28C helicopters with specific serial numbers, as well as all model 280C helicopters with serial numbers ranging from 1145 to 1169. Compliance is required within 100 hours of time in service after 31 July 1979. The directive is documented in Enstrom Service Directive Bulletin No. 0049 and highlights a known issue with the NAS 146R-57 main rotor transmission mount bolts, which have been found to have defectively formed heads. The obligations imposed by this directive are clear and specific. Owners and operators of the affected Enstrom F-28 Series helicopters must ensure that the main rotor transmission mount bolts are inspected within the stipulated timeframe. This inspection is necessary to verify that the bolts do not have the previously identified defects. The directive does not permit any deviation from the specified compliance period or from the inspection requirements. The onus is on the operator to ensure that the aircraft remains airworthy by adhering to these stringent guidelines. Failure to comply with AD/ENST 28/28 may result in severe consequences. The Civil Aviation Safety Authority (CASA) has the authority to enforce this directive and take action against non-compliance. Potential outcomes include fines, penalties, and legal action. The exact penalties can vary depending on the severity and circumstances of the breach, but the overarching principle is that the safety of air operations is paramount. In the event of a breach, CASA may impose fines up to a maximum penalty as prescribed by the Civil Aviation Act 1988. Additionally, repeated or severe non-compliance could lead to the grounding of the affected aircraft until the issue is rectified, thereby ensuring the highest standards of aviation safety are maintained.